BIOLOGY 20 A.P.
STUDY GUIDE
Holy Trinity Academy
BIOLOGY 20 Advanced Placement
Biology 20 A.P. consists of the same 4 units of study as outlined by Alberta Education Program of Studies for Biology 20 but is enhanced by additional material from the Biology Curriculum of the Advanced Placement (A.P.) Program. The following outline lists the major concepts in each of the four units from the program of studies specified by Alberta Education
Unit one: Biochemistry, Photosynthesis, and Cell Respiration 4 weeks Ch: 5, 6
Unit two: Muscles and Digestive system 3 weeks Ch 10, 6
Unit three: Circulatory system and Immunity 3 weeks Ch 8
Unit four: Breathing and Excretion 3 weeks Ch 7, 9
Unit five: Ecology, Taxonomy, and Evolution 5 weeks Ch: 1,2,3,4
Evaluation
Lab reports, quizzes 40%
Tests 35%
Final Exam 25%
Student Expectations
1. Arrive to class on time and prepared, no food or cell phones in class
2. Raise your hand to speak. Don’t speak when someone else is speaking
3. Respect each other. Be polite in word and gesture
4. Work diligently in class and complete all homework to the best of your ability
Academic Expectations
1. Hand in and receive a passing grade on all lab reports and quizzes
2. Receive a passing grade on all tests
3. Make up any missed work on the first day you return to school from an absence
4. Participate actively in all class activities.
Homework Policy
1. Late assignments loose 10% until the work is returned to class. After the assignment is returned to the class the assignment should still be completed and handed in but will lose 50%. It is the responsibility of the student to inquire about missed or alternate assignments.
2. Alternate assignments will be given to those who cannot do some dissections/labs or who miss assignments with legitimate reasons.
Supplies: 2” binder, 150 pages lined loose leaf paper, 10 pages graph paper, pen, pencil, 30 cm ruler, 1 duotang
Unit One: Energy, Photosynthesis, and Cellular Respiration
1. Growth, reproduction and maintenance of the organization of living systems require free energy and matter.
All living systems require constant input of free energy.
a. Life requires a highly ordered system. (ex. Organelles, cells, tissues, organs, systems, organism, etc.)
1. Order is maintained by constant free energy input into the system.
2. Loss of order or free energy flow results in death.
3. Increased disorder and entropy are offset by biological processes that maintain or increase order.
b. Living systems do not violate the second law of thermodynamics, which states that entropy increases over time.
1. Order is maintained by coupling cellular processes that increase entropy (and so have negative changes in free energy) with those that decrease entropy (and so have positive changes in free energy).
2. Energy input must exceed free energy lost to entropy to maintain order and power cellular processes.
3. Energetically favorable exergonic reactions, such as ATP→ADP, that have a negative change in free energy can be used to maintain or increase order in a system by being coupled with reactions that have a positive free energy change.
c. Energy-related pathways in biological systems are sequential and may be entered at multiple points in the pathway.
d. Organisms use free energy to maintain organization, grow and reproduce.
1. Organisms use various strategies to regulate body temperature and metabolism.
• Endothermy (the use of thermal energy generated by metabolism to maintain homeostatic body temperatures)
• Ectothermy (the use of external thermal energy to help regulate and maintain body temperature)
2. Reproduction and rearing of offspring require free energy beyond that used for maintenance and growth. Different organisms use various reproductive strategies in response to energy availability.
3. There is a relationship between metabolic rate per unit body mass and the size of multicellular organisms — generally, the smaller the organism, the higher the metabolic rate.
4. Excess acquired free energy versus required free energy expenditure results in energy storage or growth.
5. Insufficient acquired free energy versus required free energy expenditure results in loss of mass and, ultimately, the death of an organism.
e. Changes in free energy availability can result in changes in population size.
f. Changes in free energy availability can result in disruptions to an ecosystem.
• Change in the producer level can affect the number and size of other trophic levels.
• Change in energy resources levels such as sunlight can affect the number and size of the trophic levels.
Organisms capture and store free energy for use in biological processes.
a. Autotrophs capture free energy from physical sources in the environment.
1. Photosynthetic organisms capture free energy present in sunlight.
2. Chemosynthetic organisms capture free energy from small inorganic molecules present in their environment, and this process can occur in the absence of oxygen.
b. Heterotrophs capture free energy present in carbon compounds produced by other organisms.
1. Heterotrophs may metabolize carbohydrates, lipids and proteins by hydrolysis as sources of free energy.
2. Fermentation produces organic molecules, including alcohol and lactic acid, and it occurs in the absence of oxygen.
c. Photosynthesis first evolved in prokaryotic organisms; scientific evidence supports that prokaryotic (bacterial) photosynthesis was responsible for the production of an oxygenated atmosphere; prokaryotic photosynthetic pathways were the foundation of eukaryotic photosynthesis.
d. In prokaryotes, the passage of electrons in the plasma membrane is accompanied by the outward movement of protons across the plasma membrane for energy production.
e. Free energy becomes available for metabolism by the conversion of ATP→ADP, which is coupled to many steps in metabolic pathways.
2. describe the chemical nature of carbohydrates, fats and proteins and their enzymes, i.e.,
carbohydrases, proteases and lipases
Introduction:
The most frequently used elements in living organisms are: O, C, and H. These three are used to build carbohydrates, proteins, lipids, nucleic acids, vitamins, and water
Other elements used in smaller amounts include N (amino acids-protiens, and nucleic acids), Ca (bones),
P (energy storage and nucleic acids), Fe (RBC) Na (nerve impulse and water regulation)
Water:
Property Description Significance to life
Transparency Clear liquid Allows light to transmit through so photosynthesis can take place in water environments
Cohesion and adhesion Molecules are ‘sticky’ due to its polar nature Allows water transport in plants and organisms to live on the surface of rivers, ponds, lakes
Solvent Many substances dissolve in it; they are also polar molecules.
Lipids are nonpolar thus they will not mix/dissolve in water Allows the transport of nutrients, gases and wastes in organisms and inside cells
Thermal Has high heat capacity Protects earth and ecosystems from temp extremes, cools organisms
Minerals: are inorganic compounds or pure elements such as: Ca, Na, Fe, K
Vitamins: are organic compounds that function as coenzymes in metabolic pathways
The process of digestion involves the breaking of chemical bonds that hold the carbohydrate, proteins and fats together. This is called hydrolysis. This involves the addition of a water molecule into the carbohydrate, protein or fat splitting the compound into two smaller compounds. The opposite process, the building of a larger molecule from two smaller molecules by removing an H atom and an OH group from carbohydrates, proteins, or fats, allowing them to join together, is called dehydration synthesis, or condensation. Both processes require enzymes to make the reaction go faster.
Carbohydrates
Purpose: Store energy, structural components of cells and cell membranes
Structure: made of elements, C,H, and O
Examples: monosaccharides C6H12O6, glucose, fructose, galactose
Disaccharides C12H22O11, sucrose, maltose, lactose
Polysaccharides, glycogen, starch, wax
Of the disaccharides: Sucrose is made from glucose and fructose
Lactose is made from glucose and galactose
Maltose is made from glucose and glucose
Lipids: Fats and Oils
Purpose: store energy, protect internal organs, make hormones, structural components of cells
Fats: produced by animals and are solid
Oils: produced by plants and animals and are liquid
Structure: triglyceride fats are made from 1 glycerol molecule and three fatty acids
Polyunsaturated fatty acids: have many double bonds between carbons, creates softer substance
Monounsaturated fatty acids: have only one double bond,
Saturated fatty acids: have no double bonds, usually solid at room temperature, harder
Cholesterol: made from fat, used to make cell membranes, and important hormones
Proteins
Proteins are made from the elements C, O, H, and N. These elements link together to make an amino acid.
There are 20 different amino acids used to make all proteins for living things on earth.
Six functions of proteins:
1) enzymes—are globular proteins, speed up reactions, ex. Amylase
2) hormones—some are also made from steroids (lipids), ex. Insulin
3) antibodies—are globular proteins that help in defense against foreign substances
4) structural proteins—are fibrous proteins, ex. Tendons, cartilage, collagen, keratin
5) transport—form part of the cell membrane and regulate what enters/leaves the cell
6) carrier—pick up various substances, attach to substances, ex. Hemoglobin
Four levels of protein structure.
1) Primary structure—the linear sequence of amino acids (polypeptide) with peptide linkages between each amino acid. A peptide bond is a peptide linkage formed by dehydration synthesis. A dipeptide forms from two amino acids linked together, a polypeptide when 3 or more are linked together. Example: insulin
2) Secondary structure—the coils or sheets that occur due to hydrogen bonding between separate amino acids. This results in fibrous proteins like collagen and keratin. These are used to make hair, wool, feathers, horns antlers. These are also classified as structural proteins
3) Tertiary structure—the globular clusters that result primarily due to bisulfide bridges. Some amino acids have a sulfur molecule. When two of the sulfur atoms (in separate molecules) come together a bond forms between them. This bonding, in addition to extra hydrogen bonding, results in folding in the polypeptide. This is called a globular protein. Hemoglobin and enzymes are all examples.
4) Quartenary structure—when proteins are made of more than one polypeptide chain. They form large globular proteins like the complete hemoglobin molecule
Denature- when proteins are temporarily changed by physical or chemical processes. Enzymes are denatured by mild temperature or pH. The change is reversible.
Coagulation- when proteins are permanently changed by chemical or physical processes. If enzymes are heated too much they with ‘melt’ or break apart; frying and egg-the egg white coagulates with heat.
Tests for Carbohydrates, Proteins, and Fats
Test name Nutrient tested for Test description
Benedicts test monosaccharide Blue to yellow, green, red, brown
Iodine test Starch Orange/yellow to blue/black
Biurets test Protein Blue to pink/purple
Sudan IV test Lipid, oil, fat Pink to red
Translucence test Lipid, oil, fat Brown to semi-clear
Nucleic Acids: are found in chromosomes in the nucleus, mitochondria, and chloroplasts
Purpose: hereditary information—genes
Structure: double helix or single helix
Examples: DNA and RNA
Are made from C, H, O, and N. The basic building block (monomer) is called a nucleotide. A nucleotide consists of a sugar (deoxyribose or ribose) and phosphate, and a nitrogen base. There are four nitrogen bases in DNA (adenine, thymine, cytosine, and guanine) and four in RNA (adenine, uracil, cytosine, and guanine). The nucleotides base pair while the phosphates join to sugars. This will form a ladder like structure called a double helix in DNA, but only form a single helix in RNA.
A sequence of nitrogen bases (gene) is used as an instruction (recipe) for the cell to build proteins. Chromosomes are composed of DNA. A chromosome may contain a few genes or several thousand genes. There are three types of RNA. RNA has specific functions in the manufacture of proteins from the DNA
a. Structure and function of polymers are derived from the way their monomers are assembled.
1. In nucleic acids, biological information is encoded in sequences of nucleotide monomers. DNA and RNA differ in function and differ slightly in structure, and these structural differences account for the differing functions.
2. In proteins, the specific order of amino acids in a polypeptide (primary structure) interacts with the environment to determine the overall shape of the protein, which also involves secondary tertiary and quaternary structure and, thus, its function. The R group of an amino acid can be categorized by chemical properties (hydrophobic, hydrophilic and ionic), and the interactions of these R groups determine structure and function of that region of the protein.
3. In general, lipids are nonpolar; however, phospholipids exhibit structural properties, with polar regions that interact with other polar molecules such as water, and with nonpolar regions where differences in saturation determine the structure and function of lipids.
4. Carbohydrates are composed of sugar monomers whose structures and bonding with each other by dehydration synthesis determine the properties and functions of the molecules. Illustrative examples include: cellulose versus starch.
b. Directionality influences structure and function of the polymer.
1.. Proteins have an amino (NH2) end and a carboxyl (COOH) end, and consist of a linear sequence of amino acids connected by the formation of peptide bonds by dehydration synthesis between the amino and carboxyl groups of adjacent monomers.
2.. The nature of the bonding between carbohydrate subunits determines their relative orientation in the carbohydrate, which then determines the secondary structure of the carbohydrate, and this has implications on the function of the molecule.
3. (A.P.) Interactions between molecules affect their structure and function.
Explain enzyme action and factors influencing their action.
Enzymes
• Are all made of proteins
• Are over 1000 different enzymes in the human body
• Most names of enzymes end in ase
• Function as catalysts. A catalyst speeds up chemical reactions but are not altered by the reaction and can be used over and over again.
• They only accelerate the rates of chemical reactions that already occur, they cannot make a reaction occur that does not occur spontaneously.
The Lock and Key Model
• The enzyme is the key and the substrate is the lock
• In order to catalyze a reaction, an enzyme must come in contact with the reactant molecules
• This compound is called the enzyme-substrate complex
• The substrate attaches to the enzyme at the active site of the enzyme
• Either the substrate is broken up (catabolism) or the substrate is attached to another substrate (anabolism)
• Most enzymes have high substrate specificity, they will attach to only one type of compound (this depends on the shape of the active site)
Interactions between molecules affect their structure and function.
a. Change in the structure of a molecular system may result in a change of the function of the system.
b. The shape of enzymes, active sites and interaction with specific molecules are essential for basic functioning of the enzyme.
1. For an enzyme-mediated chemical reaction to occur, the substrate must be complementary to the surface properties (shape and charge) of the active site. In other words, the substrate must fit into the enzyme’s active site.
2. Cofactors and coenzymes affect enzyme function; this interaction relates to a structural change that alters the activity rate of the enzyme. The enzyme may only become active when all the appropriate cofactors or coenzymes are present and bind to the appropriate sites on the enzyme.
3. Other molecules and the environment in which the enzyme acts can enhance or inhibit enzyme activity. Molecules can bind reversibly or irreversibly to the active or allosteric sites, changing the activity of the enzyme.
4. The change in function of an enzyme can be interpreted from data regarding the concentrations of product or substrate as a function of time. These representations demonstrate the relationship between an enzyme’s activity, the disappearance of substrate, and/or presence of a competitive inhibitor.
How do enzymes work?
The presence of an enzyme will speed up the reaction because the active site will facilitate the chemical change. This happens by means of lowering the activation energy. Every reaction requires a certain amount of activation energy. This is the energy required to break a bond (catabolism) or to make a bond (anabolism).
Competitive inhibitors- a molecule that is similar in shape to the substrate molecule and binds to the active site preventing the substrate from attaching (there is competition for the active site. Ex. Inhibition of folic acid synthesis in bacteria by the sulfonamide drugs (antibiotics)
Noncompetitive inhibitors- a molecule binds to an enzyme, but not on its active site, causing a structural change in the enzyme which alters the shape of the active site. Ex. Heavy metals (mercury, silver) and cyanide inhibition of any enzymes in the electron transport chain
Allostery – is a form of noncompetitive inhibition. The site on the enzyme where a substance can bind is called the allosteric site. This site controls the activity of the enzyme. When a substance attaches to the allosteric site the substrate cannot attach at the active site of the enzyme (its shape changes). This is reversible when the inhibitor detaches from the allosteric site
End-product inhibition- - often the end products of a metabolic pathway act as noncompetitive inhibitors (allosteric inhibitors) of enzymes earlier in the metabolic pathway. In this way they regulate metabolism according to the requirements of the organism. Ex. ATP inhibits enzymes that cause glycolysis, thereby regulating how fast glycolysis occurs.
Factors that affect enzyme activity
Temperature: increasing temp increases enzyme activity. Above the enzymes optimum temperature excess heat will denature enzymes altering the active site rendering the enzyme inactive. Continued heating will destroy the enzyme (heat affects any protein) (results in denaturation or coagulation)
Concentration: increasing concentration of the enzyme increases the rate of the reaction, but only small amounts of enzyme are required because they can be reused and they work fast.
pH: when an enzyme is outside its pH range it is denatured decreasing its activity.
Inhibitors: they prevent the attachment of the substrate, hence slow down or stop the reaction.
Cofactors: are substances that attach on to the enzyme (other than the active site) to complete the enzyme molecule and allow the enzyme to attach to the substrate Ex. Minerals in our diet. If there are no cofactors the enzyme cannot work.
Coenzymes: are substances (vitamins) that attach on the the enzyme at the active site and allow the enzyme to attach to the substrate. If there are no coenzymes present then the enzyme cannot work.
2: Students will relate photosynthesis to storage of energy in organic compounds.
1. explain, in general terms, how pigments absorb light and transfer that energy as reducing
power in nicotinamide adenine dinucleotide phosphate (NADP), reduced nicotinamide
adenine dinucleotide phosphate (NADPH) and finally into chemical potential in adenosine
triphosphate (ATP) by chemiosmosis, describing where those processes occur in the
chloroplast
2. explain, in general terms, how the products of the light-dependent reactions, NADPH and
ATP, are used to reduce carbon in the light-independent reactions for the production of
glucose, describing where the process occurs in the chloroplast.
Photosynthesis
This process occurs in two stages:
Light dependent reaction, Photolysis, light reaction
1. This occurs in the thylakoid membranes inside the chloroplasts
2. Light is absorbed by chlorophyll ‘a’ molecules (pigments) found in clusters called photosystems
3. This light causes electrons in chlorophyll to be released
4. The released electrons are “absorbed” by chlorophyll ‘b’ molecules, as they do this ADP is joined to P to make ATP.
5. The original chlorophyll a molecules are unstable and remove electrons from water molecules, splitting water into H protons and oxygen.
6. The oxygen diffuses out of the cell and is released through the stomata
7. The H protons are added to NADP to form NADPH using electrons released by chlorophyll b.
8. NADP (nicotinamide adenine dinucleotide phosphate) is a transport truck that carries hydrogen (released from water molecules) from one reaction to another in photosynthesis, from the light dependent reaction to the light independent reaction.
Photosystems are clusters of light absorbing pigments. These are scattered throughout the thylakoid membrane. There are two types of photosystem:, photosystem I and photosystem II.
Photosystem II:
Chlorophyll a pigments found inside the thylakoid membrane, absorb light at 680nm. When photosystem II absorbs light it releases electrons which are held by other electron acceptors in the thylakoid membrane.
Photosystem I:
Chlorophyll a pigments fond inside the thylakoid membrane, absorb light at 700nm.
Photolysis of water:
Since chlorophyll molecules are missing electrons and water molecules are abundant the chlorophyll will remove electrons from water molecules causing the water molecules to break apart. This happens on the inside of the thylakoid membranes. The oxygen will be released in molecular form. The hydrogen ions accumulate inside the thylakoid membranes to be used for chemiosmosis
Photoactivation of photosystem I:
When photosystem I absorbs light it also releases electrons to electron acceptors. But photosystem I replaces its lost electrons with electrons from the electron transport (transfer) system found in the thylakoid membrane (these electrons came from photosystem II).
Electron transport:
The electrons from photosystem II go to an electron acceptor then travel through the transport system (proteins in the membrane) and replace the lost electrons in photosystem I. This movement of electrons through the membrane is called “electron transport”. As these electrons move through the transport system they release energy which is used to actively transport more hydrogen ions from the stroma outside the thylakoid membrane to the inside of the thylakoid increasing the proton gradient even greater. The hydrogen protons are used in chemiosmosis to produce ATP.
Reduction of NADP+:
The addition of H proton to NADP by electron released from photosystem I. Reduction is the gain of electrons, oxidation is the loss of electrons. The two always occur together. Something must always lose electrons in order for something to gain electrons. This only happens in photosystem I.
Photophosphorylation: the addition of phosphate to ADP, forming ATP, caused by light
Noncyclic photophosphorylation
This is the usual path the electrons flow in photosynthesis. They start from PSII, go to PSI, then PSI releases electrons which eventually end up in NADPH, which will go to the light independent reaction ending up in glucose. The electrons do not return to their original source, chlorophyll, hence the name “noncyclic”. This movement of electrons causes the build up of hydrogen ions inside the thylakoids (see electron transport) to be used for chemiosmosis and the production of ATP.
Chemiosmosis in chloroplasts
Is the movement of hydrogen ions from a high concentration to a low concentration causing the formation of ATP. The synthesis of ATP is coupled to electron transport and the movement of protons across membranes (this is known as chemiosmosis or the chemiosmostic theory). In photosynthesis photolysis occurs on the inside of the thylakoid membrane. As electrons from photosystem II pass down a series of carrier enzymes (electron transport). Electron transport causes the pumping of protons (H) to the inside of the thylakoids. The concentration of the hydrogen protons builds up, the (pH) drops, and they start to move outside again, into the stroma, but can only diffuse through special protein channels (ATP synthase) in the thylakoid membrane. When the hydrogen protons move through these channels a phosphate is added to ADP forming ATP (ATP synthesis) (phosphorylation).
Light independent reaction, Calvin Benson cycle
1. This occurs in the stroma
2. Also called carbon fixation because carbon dioxide molecules are fixed into carbohydrates.
3. NADPH move into the stroma and release their H protons
4. This Hydrogen combines with other chemicals and carbon dioxide to make carbohydrates.
5. The energy needed to create this comes from ATP breaking down into ADP and P
Compounds in the Calvin Bensen cycle
RuBp= ribulose biphosphate
RuBP carboxylase(rubisco)= the enzyme that adds carbon dioxide to RuBP forming a six carbon compound
PGA orGP= glycerate 3-phospate (phosphoglyceric acid) is a 3 carbon compound formed from the earlier 6 carbon compound
PGAL or TP=triose phosphate= glyceraldehyde 3-phosphate (phosphoglyceraldehyde)= a 3 carbon compound produced from PGA. PGAL is used to form glucose phosphate which is used to form glucose, sucrose, and starch
The Calvin cycle takes place in the stroma of the chloroplast. ATP provides the energy to “glue” some of the molecules together, and NADPH provides H and energy to glue other molecules together. RuBP is the carbon dioxide acceptor and (catalysed by RuBP carboxylase) will take up CO2, forming a 6 carbon compound. This 6 carbon compound will split in half forming 2-3carbon compounds called PGA. PGA will be reduced to PGAL but this conversion needs energy from ATP, and energy and H from NADPH. PGAL combines more PGAL to form glucose, sucrose, starch, fatty acids, amino acids, and other products. PGAL is also converted back into RuBP to keep the cycle going. This last step also requires energy from ATP.
Effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis
Temperature: As temperature increase the rate of photosynthesis increases, reaches a maximum, then decline sharply as the enzymes are denatured by the increased heat.
Light intensity: as light intensity increase the rate of photosynthesis increases then reaches a maximum and levels off
Carbon dioxide: as Carbon dioxide levels increase the rate of photosynthesis increases, reaches a maximum, then levels off. Only a low conc. is needed (less than 5 %) higher concentrations cause the pH of the cell to drop which in turn could cause the enzymes to denature.
General Outcome 2: Students will explain the role of cellular respiration in releasing energy from organic compounds.
1. explain, in general terms, how carbohydrates are oxidized by glycolysis and Krebs cycle to
produce reducing power in NADH and FADH, and chemical potential in ATP, describing
where in the cell those processes occur
2. explain, in general terms, how chemiosmosis converts the reducing power of NADH and
FADH to the chemical potential of ATP, describing where in the mitochondria the process
occurs
3. distinguish, in general terms, between animal and plant fermentation and aerobic
respiration
4. summarize and explain the role of ATP in cell metabolism
5. identifying factors affecting the rate of cellular respiration
Carbohydrate Metabolism, Glucose Metabolism, Cellular Respiration
Where does glucose come from and how does it get into the cells?
1. Polysaccharides and disaccharides are broken down to monosaccharides (glucose, fructose, and galactose.
2. These nutrients are absorbed into the blood and brought to the liver
3. The liver converts fructose and galactose into glucose. It also regulates blood glucose levels.
4. The cells absorb glucose from the blood (capillaries)
The processes that go on inside the cell (actual cell respiration)
Cellular respiration is the process where food energy, or more specifically the chemical bonds inside glucose, is converted into chemical bonds that make A.T.P. The overall reaction is as follows:
1 glucose + 6 oxygen 6 carbon dioxide + 6 water + 36 A. T. P. + waste heat
ATP—is adenosine triphosphate. This molecule store significant amounts of energy in the bond that holds the last phosphate.
The processes (reactions) that occur to break down glucose involve oxidation and reduction reactions.
Oxidation—the removal of hydrogen atoms from a molecule. The hydrogen are picked up by molecules called coenzymes.
Reduction---the addition of hydrogen atoms to another molecule. The coenzymes add the hydrogen atoms to other molecules.
N.A.D.—nicotinamide adenine dinucleotide—a coenzyme that picks up hydrogen atoms (analagous to an empty dump truck). When it picks up hydrogen it becomes N.A.D.H ( the full dump truck)
F.A.D.---Flavin adenine dinucleotide—another conezyme that picks up hydrogen atoms. It becomes FADH
Reduction always follows oxidation, with the use of enzymes and coenzymes
The Fate of Glucose
If not needed:
1. glucose is converted to glycogen, stored in the liver and muscle cells
2. if glycogen storage space is filled glucose is stored as fat
3. if glucose cannot be stored or concentrations of glucose are too high it is excreted by the kidney
If needed:
1. glucose is absorbed by the cells, is oxidized, and the energy released is stored in A.T.P. or given off as body heat
Glucose oxidation – occurs in 3 stages:
1 glycolysis—does not need oxygen
2. citric acid cycle, or Krebs cycle
3. electron transport chain
(stages 2 and 3 will only occur in the presence of oxygen.)
Glycolysis
1. occurs in the cytoplasm
2. does not use oxygen
3. splits one glucose (6carbon) into 2 pyruvic acid (3carbon)
4. produces 2 pyruvic acid, 2 NADH , 4ATP
5. uses 2 ATP to phosphorylate glucose. This prevents glucose from diffusing out of the cell as well as makes glucose more reactive
Fate of Pyruvic Acid
1. if no oxygen—pyruvic acid will be converted to lactic acid. This step uses NADH . This is called anaerobic respiration in animal cells. The lactic acid lowers pH and prevents muscle contractions. This process also occurs in some yeast cells producing alcohol instead of lactic acid as an end product, called alcoholic fermentation.
2. If oxygen is present pyruvic acid enters Krebs cycle. This occurs inside the mitochondria
Anaerobic Respiration (glucose lactic acid or alcohol) (fermentation)
1. occurs in muscle cells during strenuous exercise, when the cell uses oxygen faster than the circulatory system can provide it.
2. Not all cells in the body do this, i.e. brain cells die without oxygen
3. Lactic acid decreases pH, muscles cannot contract when pH gets to low
4. Muscle fatigue is overcome when the oxygen debt has been met by increased breathing and heart rate increasing the supply of oxygen to the muscle cells
5. Lactic acid is removed from cells and converted to glycogen in the liver
6. Net ATP produced is 2.
Aerobic Respiration
1. uses oxygen
2. occurs in any cell that has mitochondria
3. occurs in 3 stages:
a. glycolysis
b. krebs cycle
c. electron transport chain
(both b and c occur inside the mitochondria)
Mitochondria anatomy
Cristae: folded membranes inside the mitochondria, where the electron transport chain is found
Matrix: fluid inside the mitochondria surrounding the cristae, where krebs cycle occurs
Glycolysis
1. once pyruvic acid is formed it enters the mitochondria
2. when inside the mitochondria the pyruvic acid (3carbon) is converted into a new 2carbon compound called acetyl coenzyme A. For this to occur carbon dioxide is removed (decarboxylation) as well as hydrogen from NADH. This is called the “link reaction”.
Krebs cycle
1. is a cyclical process where acetyl coenzyme A is added to a 4 carbon compound to make a 6 carbon compound. This 6 carbon compound is then broken down into the original 4 carbon compound. In the process 2 carbon dioxide molecules are removed as well as NADH and FADH
2. for every one glucose molecule this cycle occurs twice.
3. This occurs in the matrix
Electron Transport Chain
1. is a series of oxidation reduction reactions that occur on the cristae
2. hydrogen are transferred from one electron acceptor (cytochrome) to another releasing energy
3. as hydrogen are moved ATP is produced
4. The last electron acceptor is the strongest, oxygen, forming water
5. If the cell lacks oxygen the E.T.C. does not function which prevents Krebs cycle from working.
6. NADH drops its hydrogen at the first cytochrome, producing 3 ATP
7. FADH drops its hydrogen at the second cytochrome, producing 2ATP
8. NAD and FAD can go back to Krebs cycle to pick up more hydrogen
Other metabolic pathways/other sources of fuel for cell respiration
1. Fats/lipids—are broken down into fatty acids and glycerol. Fatty acids enter krebs cycle and glycerol enters glycolysis
2. Proteins—are broken down into amino acids. These may enter glycolysis or krebs cycle
Pyruvic acid is also called pyruvate
Kreb’s cycle happen in the inner matix
ETC happens on the cristae
Acetyl CoA is a substance that can also be made from fatty acids or amino acids
Chemiosmosis in mitochondria
The mitochondria is composed of two membranes. An outer protective membrane and an inner membrane (called the cristae) which contains electron transport proteins and the protein ATP synthase. The mitochondria also is composed of an inner fluid called the matix containing enzymes that control the krebs cycle and the link reaction. The space between the inner and outer membranes is also filled with a fluid. . Hydrogen protons are brought to the inner membrane by NAD and FAD. The energy released by electron transport is used to actively transport hydrogen protons to the intermembrane space between the outer and inner membranes of the mitochondria. Because this space is very small a high proton concentration build up here. These protons will then diffuse through a protein channel in the membrane called ATP synthase (chemiosmosis) back into the matrix. As they diffuse ATP synthase forms ATP. Energy is released as electrons pass along the electron transport chain is used to pump hydrogen protons across the inner membrane into the intermembrane space.
Effect of pollutants: cyanide and hydrogen sulfide
These block enzymes in the electron transport chain, shutting down ATP production
Uses of ATP: muscle contractions, protein synthesis, nerve impulses, active transport
Unit 2: Human Systems: Muscles and Digestion
General Outcome 1: Students will explain the role of the motor system in the function of other body systems.
1.explain how the motor system supports body functions, i.e., circulatory, respiratory,
digestive, excretory and locomotory
Muscles are part of blood vessels and the heart, used expand our thoracic cavity to help us breath, form the digestive tract moving our food along, and control the flow of urine out of the body. But muscle are most recognized for movement, allowing us to move and carry things in our environment.
Muscular System: there are three types of muscle tissue: smooth, skeletal, and cardiac.
Body System Muscle type Function of muscles
Circulatory Smooth
cardiac Maintain pressure in arteries
Composes the heart
Digestive Smooth Peristalsis
Respiratory smooth Change thoracic volume
Skeletal Striated Body movement
Muscle
Ligaments
Tendons
Cartilage
Synovial fluid
Joint capsule
Nerves
2. describe, in general, the action of actin and myosin in muscle contraction and heat
production.
Muscle anatomy
facsia
Muscle fiber: the muscle cell
Myofibril: bundles of proteins found inside the muscle cell
Sarcomere: the contracting unit in the myofibril
Sarcoplasmic reticulum: tubules inside the muscle cell that contain calcium
Actin: thin protein filaments attached to Z band of the sarcomere
Myosin: the thick protein filaments found suspended between actin filaments; not attached to z band
Sliding filament theory: Actin filaments slide over the myosin by making attachements to the myosin. This causes the sarcomere to shorten causing the muscle cell and the muscle to shorten
Cross bridges
Steroid effects on muscles
Steroids cause increase building of the protein filaments (actin and myosin), with a resulting increase in muscle strength and bulk. They allow muscle cells to repair themselves faster after excrecise. Exercise causes tiny tears in the proteins of the myofibrils. Steroids rebuild these proteins faster than normal.
Creatine phosphate: an alternative energy source for muscle contraction; used after ATP.
3. explain that the goal of technology is to provide solutions to practical problems
• identify specific pathologies of the motor system and the technology used to treat the
conditions.
Pathologies:
Muscle cramp: a sustained, uncontrolled, maximum muscle contraction
Muscle fatique: the inability of the muscle to contract produced by a lack of ATP and buildup of lactic acid. Lactic acid lowers the pH of the cell preventing attachement of actin and myosin.
Paralysis: inability of the muscle to contract. Quadrapalegic= 4 limbs cannot move, parapalegic= 2 limbs cannot move
Muscular dystrophy: hereditary disease characterized by progressive wasting of muscles.
General Outcome 2: Students will explain how the human digestive exchange energy and matter with the environment.
1. identify the principal structures of the digestive system, i.e.,
• mouth, esophagus, stomach, sphincters, small and large intestines, liver, pancreas, gall
bladder
2. describe the chemical and physical processing of matter through the digestive system into
the bloodstream
The digestive system involves four processes:
Ingestion: the intake of food
Digestion: the breakdown of food into smaller pieces
Absorption: the movement of food molecules from the digestive tract across membranes into the blood
Egestion: the removal of the undigested waste remain of food from the body
The process of digestion occurs by two mechanisms:
Physical digestion: the mechanical breakdown of food into smaller pieces. This makes the food easier to swallow, but also increases the surface area for enzyme digestive action later.
Chemical digestion: The chemical breakdown of food from large macromolecules into smaller molecules that can be absorbed across and through membranes into the blood.
Anatomy of the Digestive System
1. The Mouth
The mouth has several functions in digestion:
a. Ingestion: the mouth is the point of entry for all food. The back of the mouth is connected to a common opening for the digestive and respiratory systems, the pharynx. The pharynx is connected to the esophagus. The esophagus moves a bolus of food to the stomach by rhythmic contractions of muscles called peristalsis.
b. Physical digestion: the mouth contains teeth, which are used to cut and grind food into smaller pieces. It addition saliva is added, containing water, which dissolves many substances, and makes food easier to swallow and taste. Each type of tooth has a specific function:
Type of tooth Number in mouth Function
Incisors 8 Cut food into pieces to swallow
Canine 4 Cut and hold food
Premolars 8 Grind food
Molars 12 Grind food
c. chemical digestion: The mouth contains saliva glands below the tongue and above the roof of the mouth. Saliva contains water and the enzyme salivary amylase. This enzyme digestions starch into disaccharide’s. The water in saliva also makes food easier to swallow and easier to taste.
d. Absorption: very little absorption happens in the mouth. Food does not stay in the mouth long enough to be absorbed, nor are the food molecules digested small enough to pass through the lining of the mouth into the blood. Some molecules that do not require digestion do pass through the lining of the mouth (alcohol, water, some drugs) but since they are not in the mouth that long not much absorption happens.
2. The Stomach
The stomach is a muscular organ that is involved in the physical and chemical digestion of food, and the absorption of some nutrients into the blood. Its primary function, however, is the physical and chemical breakdown of proteins.
Valves control the entry and exit of food into the stomach. These valves (also called sphincters) are circular muscles with hole in the middle. Contraction of the valve closes the hole, while relaxation opens it allowing food the pass through. There are two valves, one on the bottom of the esophagus, the cardiac valve, and one and the beginning of the small intestine the pyloric valve. The cardiac valve controls food entry while the pyloric valve controls food exit.
The stomach is a stretchable bag that can expand as it receives food. The inside lining has many wrinkles, called gastric rugae, that stretch out, much like an accordion, as more food enters.
The inside lining of the stomach also contains many clusters of cells called gastric glands. These cells produce the proteins pepsinogen and lipase. Other clusters of cells produce hydrochloric acid. When the pepsinogen is released it will mix with released HCl forming the enzyme pepsin. Pepsin digests large proteins (polypeptides) into smaller chain polypeptides, to be later digested in the small intestine. Pepsinogen is stored in an inactive form so that it does not digest the stomach itself, which is made of protein (an ulcer would result).
The lining also contains cells that secrete mucus. The mucus provides protection against the corrosive action of HCl as well as the digestive action of pepsin.
Small amounts of gastric lipase are also produced in the stomach. These begin the initial breakdown of fats and oils.
The mixture of food and digestive fluids in the stomach is now called chyme.
3. The Small Intestine
The small intestine has two major functions. First, to complete the chemical digestion of all the macronutrients, and second, to absorb the end products of chemical digestion into the blood stream.
The small intestine is divided into three sections. The first 20-50 cm is called the duodenum, then the jejunum and ileum. The duodenum is where the chyme from the stomach and fluids from the pancreas and gall bladder mix together. Afterwards this mixture slowly moves down the jejunum and ileum, all the while chemical digestion and absorption are occurring. The inner lining of the small intestine secretes digestive enzymes that break down disaccharides, and polypeptides (proteins).
The surface area of the small intestine has been modified in three ways to enhance absorption:
First, the inner lining has many wrinkles that increase surface area about 3 times.
Second, the inner lining has millions of finger-like projections called villi, that increase surface area a further 10 times. Inside the villi are blood vessels to which the end products of digestion travel. It is across the lining of the villi that absorption (by diffusion and active transport) of nutrients occurs.
Third, the lining of the villi has many wrinkles on its surface called micorvilli. The microvilli enhance surface area a further 20 times. Altogether all three adaptations increase the surface area of the small intestine by 600 times.
The enzymes produced by the small intestine are made by the cells that line the villi. Under the microscope these projections or wrinkles of the lining of the villi look like a brush. Hence, the enzymes are often referred to as “brush border enzymes”, these include maltose, sucrose, lactose, and peptidase.
4. The Large Intestine
The large intestine is divided into three segments. The ascending colon, transverse colon, and descending colon. The rectum is a storage organ for feces found immediately after the descending colon. A valve, the ileocaecal valve, controls the movement of material from the ileum into the caecum. The caecum is the pouch at the beginning of the large intestine (ascending colon) that receives material from the ileum. Attached to the caecum is the appendix. The appendix has no function in digestion. It may serve as a storage organ for bacteria that are important in the large intestine.
The large intestine is not involved in either physical or chemical digestion of food. Its major purpose is to reabsorb water from the waste material back into the blood. This is where fiber in the diet is important. Fiber, which is the undigestable portion of plant material (primarily cellulose, which we do not have enzymes to digest), helps to hold onto water in the large intestine. A diet high in fiber ensures enough water will remain in the feces for regular bowel movements. A low fiber diet results in too little water in the feces and constipation.
The large intestine also contains large amounts of bacteria. The bacteria help to break down some nutrients to make vitamin K, which then is absorbed into the blood stream along with water.
5. The Pancreas
The pancreas provides two functions: it produces digestive enzymes and a buffer, and regulates blood sugar.
The pancreas functions both as an endocrine and exocrine gland. Endocrine glands produce hormones that are released into the blood stream. Exocrine glands produce fluids released into tubes that travel to another body region. In digestion the pancreas produces many digestive enzymes (see chart) that are released into the pancreatic duct, travel to the duodenum, and continue the chemical digestion of the macronutrients. The pancreas also produces a buffer, sodium bicarbonate, that neutralizes the acidic chyme that enters the duodenum from the stomach. This helps the enzymes work better and prevents pepsin from digesting the lining of the small intestine.
The endocrine function of the pancreas is to produce two hormones. The hormones are produced in tiny clusters of cells called the Islets of Langerhans. There are two types of cells. The Beta cells produce insulin and the alpha cells produce glucagon. Insulin is produced when blood sugar increases (after a meal) and helps to make muscle and liver cells more permeable to glucose (blood sugar) while also converting glucose into a large polysaccharide, glycogen, in the muscle and liver cells. When blood sugar falls below normal levels the alpha cells produce glucagon which has the opposite effect. This prevents glucose from entering the cells and cause glycogen to be converted into glucose, increasing blood sugar.
6. The Liver
The liver has many functions. In digestion its main function is to produce bile. Bile causes the physical breakdown of fat and oil into smaller droplets. This is called emulsification. The bile is produced in the liver but stored in the gall bladder. A small tube carries the bile from the liver to the gall bladder. Then the gall bladder, when stimulated, releases the bile into the common bile duct which travels to the duodenum.
The liver also helps to detoxify the blood, breaking down drugs and other toxic chemicals, as well as the breakdown of dead red blood cells, and the breakdown of excess amino acids (deamination).
As discussed in the pancreas, the liver is also involved in the regulation of blood sugar. It responds to insulin and glucagon to either store or release glucose.
The liver also makes blood clotting proteins (fibrinogen), and helps in calcium uptake from the blood.
Digestive fluid Location Enzyme Function of enzyme
Saliva Mouth Salivary amylase Starch to dissacharides
Gastric juice Stomach lining Pepsin (pepsingen and HCl)
Rennin
Gastric lipase Proteins to amino acids
Coagulates milk
Fats to fatty acids and glycerol
Intestinal juice Epithelial cells of the villi Sucrase
Maltase
Lactase
Peptidase Sucrose to G. and F.
Maltose to G.and G.
Lactose to G.and Ga
Proteins to Amino acids
Pancreatic juice Pancreas Trypsin
Amylase
Lipase
Nuclease Proteins to Amino acids
Disacch to monosacch
Fats to F.A. and glycer.
Breaks apart DNA
Bile Liver No enzymes Emulsifies fat
Control of Digestive Secretions
All digestive enzymes in humans are produced in special cells. The appropriate enzyme is produced only when certain cells are stimulated. Stimulation may be provided by hormones, nerve impulses, peristalsis, or a combination of these.
Digestive juice Control
Saliva nervous-sight, smell, sound, thoughts
Gastric juice nervous, hormonal, peristalsis
Intestinal juice peristalsis
Pancreatic juice hormonal
Bile hormonal
Control of Gastric juice
1.Peristalsis of the stomach muscles causes the release of gastric juice from the inside liningof the stomach.
2.Thoughts of food result in nerve impulses sent to the stomach (by the vagus nerve) which bring about the release of gastric juice
3.Peristalsis in the stomach causes the release of a hormone, gastrin, (from special cells in the stomach) into the blood. This hormone stimulates the production and release of gastric juice.
Control of Pancreatic Juice
When food enters the duodenum its low pH causes the release of hormones from the small intestine. The hormones released, secretin and pancreozymin, stimulate the production and release of pancreatic juice. Secretin causes the release of sodium bicarbonate, and pancreozymin causes the release of the pancreatic enzymes.
Control of bile
When fatty food enters the duodenum the cells of the small intestine release another hormone, cholecystokinin. This hormone causes the gall bladder to contract, emptying its contents, bile, into the duodenum.
5. explain that the goal of technology is to provide solutions to practical problems
• explain the biological basis of nutritional deficiencies, including that of anorexia
nervosa, and the technological means available to restore equilibrium of body systems
• identify specific pathologies of the digestive system and the
technology used to treat the conditions
Disorders of the Digestive system
Heartburn: the irritation of the lower esophagus by gastric fluids squeezing through the cardiac valve
Indigestion: inadequate digestion of food, either too much gastric juice or too little gastric juice
Ulcers: a lesion on the inner lining of the stomach caused by gastric juice or bacteria
Hernia: the protrusion of a part or structure through the tissues normally containing it.
Hemorrhoids: the swelling of the veins surrounding the anus causing a protrusion
Appendicitus: the swelling of the appendix by bacterial infection
Peritonitus: the infection of the inner lining of the abdominal cavity (peritoneum) due to rupture of the appendix
Diarrhea: condition produced when too much water remains in the feces
Constipation: condition produced when too little water remains in the feces
Anorexia nervosa: a psychological and endocrine disorder primarily in young women in their teens that is characterized by a pathological fear of weight gain, leading to faulty eating patterns, malnutrition and excessive weight loss
Unit 3: Human Systems: Circulation and Immunity to Disease
General Outcome 1 : Students will explain the role of the circulatory and defense systems in maintaining an internal equilibrium.
1. describe the structure and function of blood vessels; i.e., arteries, veins, and capillaries
2. explain the role of blood in regulating body temperature
3. explain the role of the circulatory system at the capillary level in aiding the digestive,
excretory, respiratory and motor systems’ exchange of energy and matter with the environment
4. describe and explain, in general terms, the function of the lymphatic system
Functions of the Circulatory system
Delivers gases to and from body cells, nutrients to body cells, wastes away from body cells. Helps thermoregulate the body and delivers blood clotting and immune cells to help prevent disease and provide protection from the environment
Open system- allows blood cells to leave the vessels and pool in a collecting area of the body
Closed system- blood cells never leave the vessels
Composed of three components:
1. Blood vessels: arteries, veins, and capillaries
2. Pump: the heart
3. Blood: water, red blood cells, white blood cells, platelets
Blood vessels
1. Arteries
-Carry blood away from the heart
-Have thicker muscles in their walls
-Have higher pressure
-Carry oxygenated blood except in one case
2. Veins
-Carry blood to the heart
-Have thin muscles in their walls
-Have low pressure
-Have valves that prevent the back flow of blood. The valves prevent the blood from pooling in the lower extremities. Skeletal muscle contractions also help to push the blood in veins to ensure an adequate volume returns to the heart.
-Carry deoxygenated blood except in one case
3. Capillaries
-Connect arteries and veins
-Have very thin walls to allow for the exchange of gases, water, nutrients and wastes between body cells and the blood. Some white blood cells can also pass through the capillary walls.
-The pressure drops from medium to low as it passes through the capillaries
-Have circular muscles around the arteriole end to regulate the flow of blood through capillaries. This is called vasoconstriction and vasodilation. In the skin this helps to conserve heat or increase heat loss respectively.
-They are the most numerous type of vessel.
The lymphatic system
Is a system to accessory vessels throughout the body that empty into the superior vena cava, and lymph nodes, lymph, the spleen and thymus gland.
The lymphoid organs have specific functions that assist immunity:
Lymph nodes: clean lymph Spleen: cleans the blood Thymus: where T lymphocytes mature
4. identify the principal structures of the heart and associated blood vessels, i.e., atria,
ventricles, septa, valves, aorta, vena cavae, pulmonary arteries and veins, sinoatrial node
5. describe the action of the heart and the general circulation of the blood through coronary,
pulmonary and systemic pathways
The Heart
Pericardium: a thin membrane sac that surrounds the heart. This helps reduce friction between the heart and lungs and chest cavity.
Atria: the receiving chambers of the heart, they are smaller and made of less muscle, they collect blood and pump it to the ventricles
Ventricles: are the major pumps of the heart, they receive blood from the atria and pump it to all body parts
Valves: are found in the major arteries leaving the heart and between the atria and ventricles. They prevent the back flow of blood
Right atrium: receives deoxygenated blood from vena cavas
Left atrium: receives oxygenated blood from pulmonary vein
Right ventricle: pumps deoxygenated blood to lungs
Left ventricle: pumps oxygenated blood to body parts
Aortic semilunar valve: prevents back flow of blood into the left ventricle
Pulmonary semilunar valve: prevents back flow of blood into right ventricle
Tricuspid valve: prevents back flow of blood into right atrium
Bicuspid valve: prevents back flow of blood into left atrium
Inferior vena cava: brings deoxygenated blood from below shoulders to right atrium
Superior vena cava: brings deoxygenated blood from above shoulder and above to right atrium
Pulmonary vein: brings oxygenated blood to the left atrium from the lungs
Pulmonary artery: brings deoxygenated blood to the lungs from the right ventricle
Dorsal aorta: brings oxygenated blood from left ventricle to all body parts
Blood flow through the heart
Superior and inferior vena cava-----right atrium----tricuspid valve----right ventricle----pulmonary semilunar valve----pulmonary artery----lungs----pulmonary vein----left atrium----bicuspid valve----left ventricle-----aortic semilunar valve----dorsal aorta----body parts.
The right side of the heart always has deoxygenated blood, while the left side of the heart always has oxygenated blood. The atria always contract simultaneously while the ventricles relax, and when the atria relax the ventricles contract simultaneously.
Regulation of Heart beat
The heart has a built in conduction system.
The sinoatrial (s-a) node starts each cardiac cycle; it sets the pace for the heart (called the pacemaker). It is located in the upper right corner of the right atrium. It causes the contraction of the atria and stimulates the a-v node. The a-v node (atrioventricular node) stimulated the muscles of the ventricles to contract through a large nerve called the purkinje fibers
An electrocardiogram is a print out of the electrical activity of the heart; the activity of the s-a and a-v nodes.
Heart Sounds
The heart beat consists of two sounds. The first sound is caused by the closing of the bicuspid and tricuspid valves. When blood pushed by the ventricles hits these valves they close and the blood hitting them makes a sound. The second sound is caused by the closing of the semilunar valves. When the ventricles relax blood in the pulmonary artery and aorta start to move backwards into the ventricles. The blood hits these valves causing them to close, making a sound.
A stethoscope is an instrument used to listen to the heart sounds
Blood Pressure
Blood pressure is created both when the ventricles contract and relax. It is a measure of the force of the blood in the blood vessels. Higher pressure results when the ventricles contract (systolic pressure). A lower pressure results when the ventricles are relaxed, not pumping (diastolic pressure). Pressure is recorded as a fraction with units in mm of Hg: 120/80. The upper number is the systolic pressure while the bottom number is the diastolic pressure.
Factors that influence blood pressure include: amount of blood in the body, pulse, size of artery, viscosity of the blood, distance from the heart, stress, diet, genetics.
A sphymomanometer is an instrument that measures blood pressure
Cardiac output
A measure of the amount of blood the heart pumps out during a given time interval. The average heart pumps out about 70 ml of blood each beat (volume from the left ventricle).
Pulse
The surge of blood through an artery created when the left ventricle contracts.
Disorders-Pathologies
Heart attack: increased activity of the heart often due to an area of the heart (muscle group) that is not working or has even died.
Artheriosclerosis: hardening of the arteries. This decreases the inner diameter of an artery increasing resistance to blood flow, increasing blood pressure. The plague can also cause platelets to release their clotting factors causing the formation of a blood clot (thrombosis) around the plaque. This clot may dislodge travel with the blood further down the artery and lodge in smaller arteries depriving the tissues that was supplied by this artery of oxygen. If this happens in heart tissue it places a strain on the heart decreasing heart muscle lifespan. This may lead to a heart attack especially if the artery is the one taking blood to the heart muscles themselves. If the heart muscles are deprived of blood (and oxygen) they will eventually die leading to the rest of the heart beating faster and harder to compensate for the loss of muscle. This often leads to a heart attack.
Stroke. This occurs when a blood vessel in a part of the brain ruptures, or a clot (thrombosis) forms in a vessel in the brain causing part of the brain to not get oxygen and those cells die.
Varicose veins. This occurs when the veins remain dilated or stretched out and the valves do not close properly allowing the blood to pool in the vein , usually in the legs.
Aneurism The dilation of an artery
Technologies
Artificial valves: mechanical valves of metal cages and plastic balls to replace natural (defective) valves
Bypass surgery: sewing an artery around a plaque buildup in the coronary artery of the heart
Shunt: a metal cage placed in an artery to keep it open, or to open it up wider
Dyes: are used to highlight blood flow through the coronary artery and identify blockages
Angioplasty: inserting a tiny tube with a tiny balloon on the end into a blocked artery and expanding the balloon to open up the artery
Pacemaker: an electronic devices to control the pace of the s-a node.
Artifical heart: a mechanical pump to take the place of the natural heart
Xenotransplants: placing the organ of another animal into humans, ex. Baboon and human heart transplants
6. describe the main components of blood and their role in transport and in resisting the
influence of pathogens; i.e., erythrocytes, leucocytes, platelets, plasma
7. list the main cellular and non-cellular components of the human defense system and
describe their role, i.e., skin, macrophage, helper T cell, B cell, killer T cell, suppressor T
cell, memory T cell.
The Blood: composed of 55% plasma and 45% cells
Plasma: mostly water, has dissolved nutrients, wastes, gases, hormones, and other special proteins
Red blood cells -- Erythrocytes
-formed in the bone marrow
-have no nucleus
-live about 120 days
-broken down in spleen and liver
-contain the chemical hemoglobin which has a strong attraction for oxygen
-stay in vessels, leave only if vessel is damaged
-shaped like a bagel; this decreases the size of the cell (so they can fit through the capillaries) yet maintains surface area (for efficient gas exchange)
-the lower the oxygen concentration in the air the greater the rbc production by the bone marrow
-there are 4 major blood types determined by protein markers on the rbc (type A,B, AB, O)
Blood types and transfusions
ABO group: this consists of specific proteins (antigens) found on the red blood cell membrane. You can have either A or B or both proteins. The absence of both proteins means you have type O blood
RH group: the rhesus factor, another protein on the red blood cell membrane. Rh positive means you have this protein, RH negative means you do not have the protein
Type Antigen antibody
A A B
B B A
AB AB Neither
O Neither A and B
Always consider the antibodies in the receivers’ blood and the proteins in the donors’ blood to determine is a match will occur. The antibodies in the receivers’ blood with attack the proteins in the donors’ blood.
Type O blood is called the universal donor because it contains neither A or B protein, while type AB blood is called the universal receiver because it contains no antibodies to A or B blood.
Blood type matching
Receivers blood (antibodies in brackets)
Donors blood A(B) B(A) AB(NEITHER) O(AB)
A Match Agglutinate Match Agglutinate
B Agglutinate Match Match Agglutinate
AB Agglutinate Agglutinate Match Agglutinate
O Match Match Match Match
RH factor: is another protein (antigen) found on the cell membrane of rbc’s. If you have this protein you are RH positive and cannot produce antibodies to the RH factor, if you donot have this protein you are RH negative and can produce antibodies to the RH factor. Therefore a person who is RH negative cannot receive RH positive blood, but someone who is RH positive can receive RH negative blood.
White blood cells -- Leukocytes
-produced in the bone marrow, can leave the blood vessels through the capillary walls
-have a nucleus
-lifespan varies with what they are exposed to
-one wbc for every 600 rbc
-fight infections directly by phagocytosis
-fight infections inderectly by producing antibodies
-high wbc count can mean the body is fighting an infection, there are other explanations for high wbc
-pus is destroyed wbc, bacteria, and interstitial fluid
B cells – cause antibodies to be made
Helper T cell- stimulates B cells to make antibodies and killer T cells to work
Killer T cell- kills infected cells and cancer cells
Suppressor T cell- shuts down immune response
Memory T cell- a clone of long lived lymphocytes that remain in the lymph node until activated by exposure to the same antigen that triggered its formation. They will stimulate B cells to produce antibodies
Antibodies- a protein produced by B cells that bring about an effect on the pathogen/antigen
Histamines: are released by special white blood cells (basophils) and cause both dilation and increased permeability of nearby capillaries
Platelets -- thrombocytes
-produced in the bone marrow
-are fragments of cells that contain blood clotting proteins (factors, specifically Thromboplastin/thrombokinase)
Disorders of the circulatory system: Pathologies
Anemia: lack of red blood cells, due to lack of iron (iron is needed to make hemoglobin), characterized by general continuous tired feeling.
Hemophilia: lack of the ability of the blood to clot, due to low platelets, or lack of a blood clotting factor (protein)
Bacterial infection: indicated by increased white blood cell count
Mononucleosis: the presence of abnormally large number white blood cells in the blood. This reduces red blood cell numbers causing lack of oxygen and fatigue associated with this disease.
Technologies
Vaccinations: provide immunity to severe diseases but in some cases can cause harmful, lethal side effects
Blood transfusions: Add blood from a different person to another.
Blood testing: taking small sample of blood and testing for gases, drugs, hormones, or other substances.
HIV is the abbreviation for the Human Immunodeficiency Virus that causes the disease AIDS (acquired immune deficiency syndrome). It effects the immune system the virus destroys the helper T cells (discussed later) allowing other pathogens the body normally would fight off to caused life threatening infections.
Defense against Infectious Disease
1. Disease is any change, other than injury, which interferes with the normal functioning of the body.
2. The skin and mucous membranes are our first line of defense, acting as a barrier to pathogens. Areas where the skin opens to the environment are often protected by mucus, hair, tears, or acidity
3. Since our skin is the first line of defense any break in the skin must immediately be fixed. A blood clot (thrombosis) occurs whenever a blood vessel is broken, internally or externally.
a. damaged platelets release thrombokinase (thromboplastin) which combines with calcium in the blood to change a protein in the blood (prothrombin, requires vitamin k for its production) into thrombin.
b. Thrombin converts another protein in the blood (fibrinogen) into a new protein called fibrin. The fibrin forms a net to capture red blood cells and form the clot preventing further blood loss
4. If pathogens should enter the body this is called an infection. Leukocyctes (wbc) are found in the blood, lymph and fluid around all our cells. Special types of wbc’s eat pathogens, the macrophages or monocytes and the neutrophils, this is called phagocytosis.
5. The phagocytic wbc’s (monocytes and neutrophils) can recognize pathogens from normal cells by special proteins (antigens) on the outer membranes of the pathogens.
6. MHC proteins: major histocompatability complex: are proteins on the surface of every cell in your body. They are your identity tag to the macrophages and T cells and B cells. They are also found on any other cell but are specific to that organism so the macrophages, T cells, and B cells use these to identify antigens from your cells
7. Antibodies (Immunoglobulins) are produced by B-cells (B-lymphocytes), a wbc, and travel to the lymph nodes. The antibodies stick to the antigen and cause the antigens (and thus the pathogen) to stick together as well as making the antigen/pathogen a better target for other macrophages.
8. Lymphocytes. A group of white blood cells produced in the bone marrow. They include B and T cells
9. Lymph nodes. Most are tiny bean shaped glands found in the next, armpit and groin regions of the body. The tonsils and adenoids (in your nose) are the largest lymph nodes. They store white blood cells and filter the lymph fluid.
10. B-cells: mature in lymph nodes and produce one kind of antibody to a specific antigen
Helper T cells: Mature in the thymus gland. When the macrophage presents an antigen to the helper T cell the T cell becomes active and secretes a chemical (lymphokines) which activates B cells in the lymph nodes. This causes the B cells to divide, forming clones, and produce antibodies to the MHC on the pathogen/antigen
Cytotoxic T cells or killer T cells: Produced in the thymus gland. In response to chemicals secreted by the helper T cell the cytotoxic T cell will puncture holes in pathogen cells or even body cells that contain the pathogen/antigen, killing the pathogen or body cell. The killer T cells kill virus infected cells and tumor cells by cell to cell contact.
Memory cells: Believed to be either B cells or T cells that remain behind after the infection is gone. If the same antigen appears again these memory cells produce antibodies immediately (the whole process does not have to happen), often in the second infection no symptoms are evident.
11. By immunizing people, when they come into contact with a pathogen the body will react much faster and have a stronger response and the person will be less likely to become ill, or show symptoms of the disease
12. Immunization involves the deliberate exposure (often by injection through vaccination) to the pathogen ( a weakened form, dead form, related form, or chemical product of the pathogen) in order to produce the memory cells or antibodies in the recepient. To avoid becoming ill as a result of this exposure, the pathogen is killed, or weakened or a related noninfectious from is used.
13. Immunization prevents epidemics of disease, has saved many lives, and has all but totally eliminated many diseases that plagued mankind for years. Ex. Smallpox, TB, hepatitis, polio. In some cases though vaccines are not always safe and may cause the disease or other problems, even death. It is still believed that the benefits outweigh the negative effects.
Specific immunity (involves B cells and T cells)
When nonspecific defenses have failed to prevent an infection, specific defenses come into play.
B cells
When a macrophage with a pathogen accumulate at the lymph nodes and thymus gland they expose the pathogen to T cells. The T cell is activated by the pathogens antigen protruding from the cell membrane of the macrophage The T cell then activates B cells. . The B cell becomes activated and divides many times. The new B cells produced are mature B cells called plasma cells that mass-produce specific antibodies to the pathogen encountered. Once the threat of infection has passed, the development of new plasma cells ceases and those present undergo a programmed cell death. A few B cells remain to allow for long term immunity. They can produce antibodies very quickly when presented with the same antigen again (the next time the pathogen/infection is acquired). These cells are called memory cells.
T cells
Helper T cells regulate immunity by enhancing B cell division and stimulating killer T cells
When a macrophage presents an antigen from a pathogen to a helper T cell, the helper T cell is stimulated
to divide (clonal expansion) and produces chemicals that stimulate other immune cells (B cells and killer T cells). When the killer T cell is activated it also undergoes clonal expansion and destroys any cell in the body that possesses that specific antigen (pathogen). As amount of this antigen decreases in the blood the T cells go through a programmed cell death, leaving behind only a few helper T cells that also act as memory cells providing long term immunity to that pathogen.
Pathogen infection
Skin and mucous membranes
Blood clot (thrombosis)
Phagocytosis by monocytes (macrophage) and neutrophils
Mast cells release histamine
To thymus gland to lymph nodes
Clonal selection clonal selection
Lymphoctes + lymphokine Helper T cells
Clonal expansion B cells
Memory Killer suppressor Helper clonal expansion
T cells T cells T cells T cells
Memory Plasma
B cells cells
Produce
Antibodies
Attach to
Antigens
Plants and animals have a variety of chemical defenses against infections that affect dynamic homeostasis.
a. Plants, invertebrates and vertebrates have multiple, nonspecific immune responses.
• Invertebrate immune systems have nonspecific response mechanisms, but they lack pathogen-specific defense responses.
• Plant defenses against pathogens include molecular recognition systems with systemic responses; infection triggers chemical responses that destroy infected and adjacent cells, thus localizing the effects.
• Vertebrate immune systems have nonspecific and nonheritable defense mechanisms against pathogens.
b. Mammals use specific immune responses triggered by natural or artificial agents that disrupt dynamic homeostasis.
1. The mammalian immune system includes two types of specific responses: cell mediated and humoral.
2. In the cell-mediated response, cytotoxic T cells, a type of lymphocytic white blood cell, “target” intracellular pathogens when antigens are displayed on the outside of the cells.
3. In the humoral response, B cells, a type of lymphocytic white blood cell, produce antibodies against specific antigens.
4. Antigens are recognized by antibodies to the antigen.
5. Antibodies are proteins produced by B cells, and each antibody is specific to a particular antigen.
6. A second exposure to an antigen results in a more rapid and enhanced immune response
Unit 4: Human Systems: Excretion and Breathing
General Outcome 1: Students will explain the role of the excretory system in maintaining an internal equilibrium in humans through the exchange of energy and matter with the environment.
1. identify the principal structures of the excretory system, i.e., kidneys, ureters, urinary
bladder, urethra
• observing the principal features of a mammalian excretory system and identifying
structures from drawings obtained from various print and electronic sources
2. describe the function of the kidney in excreting metabolic wastes and expelling them into
the environment.
Purpose of excretion
Excretion involves any process which removes metabolic wastes from the body.
Animal waste includes urea, uric acid and ammonia, Plant waste includes CO2, H2O and O2
This is performed by the skin, lungs, large intestine/rectum, and kidneys (organs of excretion).
The major organ of excretion is the kidney.
The kidney is also involved in regulating water concentration of the blood. (osmoregulation)
The kidney also maintains the acid base balance in our bodies by regulating the H ion conc.
The major waste product in the blood is urea. Urea is produced by the liver in a process called deamination
Deamination involves the breakdown of amino acids, and occurs in the liver. Amino acids are broken
down into the amine group and a carboxylic acid. The carboxylic acid can be used in cellular respiration. The amine group is combined with another hydrogen atom to make ammonia. Then, since ammonia is very toxic to body cells it is converted to a less toxic compound, urea, by the addition of carbon dioxide. Also several urea molecules can be combined to form uric acid. The liver dumps urea and uric acid in to the blood. The kidneys filter these wastes from the blood and produce urine.
Organ Excretory substance
Lungs Carbon dioxide, water
Skin Water, urea, salts
Intestine Undigested material, bile
Kidneys Water, salts, urea, uric acid
Excretory system anatomy
Kidney: primary function is to remove nitrogenous waste from the blood, see other functions above.
Renal artery: brings blood in high pressure and high nitrogen waste to the kidney
Renal vein: takes cleaned blood away from the kidney back to the inferior vena cava
Ureter: takes urine from kidney to urinary bladder
Urethra: takes urine from bladder to outside environment
Urinary bladder: hold urine in the body
Kidney anatomy
Renal cortex: the outermost layer of the kidney where the filtering unit, the nephron, is found
Renal medulla: the middle region of the kidney. It is composed of arteries and veins, bringing blood to and from the cortex nephron, and tubules that carry urine from the nephron to the central core of the kidney
Renal pelvis: The hollow central core of the kidney. Urine from all the nephrons drains into this area. The pelvis exists the kidney through the ureter.
Nephron: the microscopic filtering unit of the kidney. There are approximately 500,000 of theses in each kidney
3. explain the structure and function of the nephron in maintaining normal body fluid
composition, i.e., water, pH, ions
Nephron anatomy
Afferent arteriole: brings blood into the glomerulus
Glomerulus: filters the blood, it allows a portion of the plasma to escape but retains the large red blood cells and large proteins. The plasma that leaves the glomerulus is called the filtrate. It contains tiny pores that only allow small molecules to leave (fenestrated capillaries)
Efferent arteriole: brings blood out of the glomerulus and branches to form the capillary net
Capillary net: surrounds the nephron and absorbs water, ions, and nutrients from the tubules
Bowman’s capsule: collects the filtered plasma (filtrate) from the glomerulus
Proximal convoluted tubule: filtrate from Bowman’s capsule travels through this tube. Ions, nutrients and water are removed from the filtrate and move back into the blood in the capillary net.
Distal convoluted tubule: the last section of the nephron. This makes the final adjustment to water in the urine. It is affected by ADH. ADH increases the permeability of the DCT to water, consequently more water travels out of the DCT back into the blood in the capillary net.
Loop of Henle: extends from the renal cortex into the renal medulla. As it extends into the medulla region the medulla region gets saltier due to the active transport of sodium out of the filtrate. This helps to draw out water. But the ascending loop of Henle is impermeable to water. Still sodium is being actively transported out of the ascending loop. This makes the urine hypotonic while the medulla region is hypertonic.
Collecting duct: the DCT of each nephron connects to this tube. The collecting ducts all connect together internally at the hollow renal pelvis. Urine from each nephron flows into the collecting duct and then to the renal pelvis.
Processes that occur in the nephron
1. Filtration
Sometimes also called force filtration. The blood pressure in the glomerulus forces about 20% of the blood out into Bowman’s capsule. About 600 ml of blood flows through the kidney each minute. About 120 ml fluid each minute is forced into Bowman’s capsule. Red blood cells, plasma proteins, and platelets are too large to pass through the glomerulus into Bowman’s capsule.
2. Reabsorption
Only 1ml of the 120 ml will form urine. The rest is reabsorbed by different sections of the nephron. Selective reabsorption by both active and passive transports moves the particles and water back into the blood in the capillary net. First sodium ions, glucose and amino acids are active transported from the filtrate into the blood. This requires ATP provided by mitochondria. Then negative ions (chloride and bicarbonate) follow by charge attraction. The build up of all these particles in the blood and renal medulla creates a hypertonic blood compared to the filtrate (which is now hypotonic). This concentration is highest at the tip of the loop of Henle which is in the center of the renal medulla region of the kidney. This is the osmotic gradient. Water will move passively, by diffusion, from the filtrate into the blood to equalize this concentration difference. Most of the nutrients, ions, and water is reabsorbed in the PCT with the remaining sodium and chloride ion and water reabsorption happening in the loop of Henle and DCT.
3. Secretion
This involves the active secretion of waste substances from the blood in the capillary net into the collecting duct. These wastes include ammonia, urea, uric acid, histamines, excess hydrogen ions, minerals, and excess drugs (penicillin). This requires active transport and significant amounts of energy from ATP.
Regulation of water (Osmoregulation)
ADH: antidiuretic hormone, produced by the pituitary gland. A diuretic is any substance that increases urine volume. This hormone increases the permeability of the DCT and collecting duct to water. Since the urine is hypotonic and the renal medulla is hypertonic water will flow out of the collecting duct into the capillaries in these regions, decreasing urine volume.
Osmoreceptors: are specialized nerve cells that detect changes in water concentration (osmotic pressure). These receptors are found in the brain (hypothalamus). They will signal the pituitary to produce more ADH whenever blood water concentration decreases.
Aldosterone: A hormone produced by the adrenal cortex. It increases sodium reabsorption from all parts of the nephron. This leads to greater water reabsorption from the filtrate/urine into the blood.
Alcohol: Prevents the hypothalamus (brain) stimulation of the pituitary. This decreases ADH production and results in large volumes of urine. This also causes dehydration.
Regulation of pH (acid – base balance)
Active transport of Hydrogen ions from the blood into the collecting duct (tubular secretion) helps to regulate the pH of the blood. If excess hydrogen ions are present then the pH is too low and active transport increases. This decreases hydrogen ions increasing pH back to normal levels.
Disorders of the excretory system
Diabetes mellitus: the inadequate production of or inability to produce insulin. This results in too much blood sugar (glucose). As the filtrate goes through the nephron it does not lose enough glucose (by active transport back into the blood). This excess glucose retains/holds water in the urine increasing urine output and causing dehydration.
Diabetes insipidus: caused by the inability to produce ADH in the pituitary gland. This results in large volumes of urine and dehydration and possibly death in extreme cases or untreated cases.
Nephritis: an inflamation of the nephron.
Kidney stones: formed by the precipitation of mineral solutes in the urine. This produces tiny stones that move with the urine and cause extreme pain as they move through the ureter and urethra.
Edema: an accumulation of excess fluid in cells, tissues, or body cavities. This can be produced by an imbalance of ion, proteins, or damaged tissue.
Renal dialysis: A dialysis machine is used to clean the blood in people whose kidneys are no longer functional. The blood enters the machine (from an artery in the arm) and passes through a series of dialysis tubes. The tubes are semipermeable membranes. The tubes a bathed in dialysis solution which is similar to clean blood plasma (plasma minus urea, uric acid, excess hydrogen ions, and ammonia). Consequently, the waste materials in the blood diffuse out into the dialysis solution and the cleaned blood is returned to the body through an tube connected to a vein in the arm.
Peritoneal dialysis: This involves attaching a bag of dialysis solution to a tube that is permanently attached to the lower abdomen. The dialysis solution is drained into the lower abdominal cavity (the peritoneum) and left there for a few hours. During this time the waste in the capillaries of the blood lining the peritoneum diffuse out into the clean dialysis solution. After a few hours the bag is lowered and the dialysis fluid is allowed to drain out, back into the bag.
General Outcome 2: Students will explain how the respiratory system exchanges energy and matter with the environment.
1. identify the principal structures of the respiratory system i.e.
• nasal passages, pharynx, larynx, epiglottis, trachea, bronchi, bronchioles, alveoli,
diaphragm, rib muscles, pleural membranes
2. explain how gases and heat are exchanged between the human organism and its
environment, i.e., mechanism of breathing, gas exchange, removal of foreign material.
describe the mechanism by which inhalation and exhalation occur
describe the mechanisms involved in the control of breathing
3. explain that the goal of technology is to provide solutions to practical problems
• identify specific pathologies of the respiratory system and the technology used to treat the conditions
The Respiratory system
Respiration: refers to the cell processes that produce energy. Primarily cellular respiration
Breathing: refers to the exchange of gases between the atmosphere and the lungs
Respiratory System Anatomy
Nasal Sinuses: warm and clean the air
Pharynx: connect sinuses and mouth to trachea
Uvula: small tissue at top of pharynx that prevents food from entering the nose when we swallow
Epiglottus: small tissue that covers the entrance to the trachea (glottis) when we swallow food
Larynx: the voicebox, It sits ontop of the trachea and produces sounds as air moves over the vocal cords
Thoracic cavity: the chest cavity in which the lungs and heart are located.
Trachea: the windpipe. Brings air into and out of the lungs
Bronchi: the two major branches off the trachea that bring air into the right and left lung
Cilia: fine, tiny hairs that trap dust; they clean the air.
Bronchioles: subdivisions of the bronchi that terminate in clusters of air sacs called alveoli
Alveoli: tiny air sacs that have thin membranes and are lined with capillaries. Gases exchange between the air and the blood occurs across this membrane
Diaphragm: the muscle below the lungs that aids in breathing
Internal intercostal muscles: muscles that pull the ribcage downward during extreme exercise. These are not used during normal breathing. They cause forced breathing out.
External intercostal muscles: muscles found between the ribs that raise the ribcage, pulling it up and out causing air to move into the lungs
Pleural membranes: surround the lungs and line the inside of the thoracic cavity. A fluid between these two membranes helps reduce friction between the lungs and the chest cavity and other organs (heart, and blood vessels).
The Mechanics of Breathing:
Inhalation
1. intercostal muscles and diaphragm contract
2. thoracic volume increases
3. air pressure inside lungs decreases
4. air from outside (higher pressure) flows into the lungs through nose and mouth
Exhalation
1. intercostal muscles and diaphragm relax
2. thoracic volume decreases
3. air pressure inside lungs increases
4. air inside the lungs is forced out into the atmosphere (now at a lower pressure relative to lungs).
Lung volume terminology
Tidal volume: the volume of air inhaled and exhaled under normal breaths
Inspiratory reserve volume: the extra air that can possibly be inhaled after a normal breath in.
Expiratory reserve volume: the extra air that can possibly be exhaled after a normal breath out.
Vital capacity: the sum of the tidal volume, inspiratory reserve, and expiratory reserve.
Reserve volume: extra air left in the lungs after the expiratory reserve volume.
Total lung capacity: the sum of vital capacity and reserve volume
Transport of Gases by the blood
Oxygen
1. dissolved in plasma 1%
2. carried by hemoglobin in red blood cell 99% (forms oxyhemoglobin)
Carbon dioxide
1. dissolved in plasma as CO2 9%
2. carried in plasma as bicarbonate ions 64%
CO2 + H2O react together in a red blood cell where the enzyme carbonic anhydrase speeds up this reaction forming hydrogen carbonate H2CO3. This compound then breaks down into hydrogen ions H+ and bicarbonate ions HCO3- which diffuse out of the red blood cell into the plasma.
3.attached to hemoglobin in the red blood cell forming carbaminohemoglobin 27%
Regulation of Breathing
Breathing is under both voluntary and involuntary control
Chemoreceptors in the medulla oblongata (part of the brain) are sensitive to the concentration of carbon dioxide and hydrogen ions in the blood.
When the concentrations of these two chemicals in the blood increases this stimulates the medulla to stimulate the intercostal and diaphragm muscles causing breathing rate to speed up.
Disorders of the respiratory system
Lung cancer: the uncontrolled growth of cancer cells in the lungs. Most often caused by smoking. The tumors take up space in the lungs decreasing surface area for gas exchange leading to emphysema and eventual death.
Bronchitus: an irritation of the cells that line the bronchial tubes causing an increase in mucus production and tissue swelling. This impairs air flow into and out of the lungs
Asthma: a stimulus causes the bronchiole diameter to decrease making breathing very hard and reducing oxygen diffusion into the blood and increases blood carbon dioxide.
Emphysema: a buildup of air pressure in the lungs causing a swelling of the alveoli and eventual rupture. This a long term condition that develops as a result of prolong asthma or smoking. This decrease lung surface area and oxygen intake in the blood.
Unit 5: Energy and Matter Exchange in the Biosphere
Ecology, Taxonomy, and Evolution
General Outcome 1 : Students will explain the constant flow of energy through the biosphere and ecosystems.
1. explain, in general terms, the one-way flow of energy through the biosphere and how stored
biological energy in the biosphere, as a system, is eventually lost as heat.
1. The energy the earth/biosphere receives over the long term always balances the energy it gives off. This satisfies the first law of thermodynamics. The second law of thermodynamics states that when energy is converted from one form to another the conversion is never 100% efficient. Much of the energy is lost as heat. This is the heat radiated from the atmosphere, lithosphere, and hydrosphere. Examples of conversions that release heat are decomposition and muscle contractions
2. First Law of Thermodynamics: The energy that goes into a system must equal the energy that comes out of a system. Energy in = Energy out.
Second Law of Thermodynamics: Any energy conversion is never 100 % efficient. Some energy is always lost as heat.
3. Energy flow through the biosphere (distribution of solar energy through the biosphere). The biosphere consists of the atmosphere, hydrosphere, and lithosphere. Different areas of the biosphere receive different amounts of energy (latitude, surface features, weather patterns). Different amounts of energy produce different patterns of life (ecosystems)
4. Overall energy always flow through a system, it drives the system. Energy flows, which in turn causes matter to cycle and life to exist. It may be temporarily stored, and given off later, it may be changed from one form to another, but it is never lost. Examples of energy storage processes in the biosphere are photosynthesis and chemosynthesis.
5. Photosynthesis: occurs in plants, some protozoa, and some bacteria. It is a chemical reaction that stores energy from sunlight in the chemical bonds of glucose and other sugars. It uses carbon dioxide and water, occurs in special cell organelles (chloroplasts in plants cells) and produces sugars and oxygen
6. Chemosynthesis: is a process that occurs in some bacteria that usually live in habitats with no light. These organisms use the organic chemicals in the environment around them to produce carbohydrates. The energy to link the molecules together comes from heat in the surrounding environment. Usually these bacteria are found in the ocean floor around geothermal vents (hot water springs)
7. Energy transfer through the biosphere is by conduction, convection, or radiation, or by energy stored in compounds in organisms which then pass the energy onto other organisms when they are eaten or decomposed.
Conduction: transfer of energy by direct contact ex. Heat transfer through metal bar
Convection: transfer of energy through a fluid ex. Warm air rises, convection currents
Radiation: transfer of energy through electromagnetic waves, ex. Light, microwaves, infrared
2. explain how biological energy in the biosphere can be perceived as a balance between both
photosynthetic and chemosynthetic, and cellular respiratory activities
Photosynthesis and chemosynthesis both store energy in larger carbohydrate molecules. Cell respiration takes the large carbohydrate molecules and slowly releases this energy. The energy is used to do cellular processes (metabolism) such as building other molecules and is used to keep the cell warm. The waste products of respiration are reused by photosynthesis or indirectly by chemosynthesis to form the large carbohydrates again.
Energy flow in photosynthetic environments starts with the sun (visible light) and continues through plants to animals and finishes with decomposers, forming food chains and webs.
Energy flow in deep sea vents starts with thermal energy from the water (produces by nuclear breakdown of matter in the Earths crust) to bacteria to protozoa to animals to decomposers.
As light intensity increases the rate of photosynthesis increases and the amount of energy storage by plants increases (their carbohydrate production increases).
3. explain the structure of ecosystem trophic levels, using models such as food chains and
webs
1. Ecology: the study of ecosystems
2. Ecosystem: A community and its physical and chemical environment
3. Habitat: The environment a specific organism survives in.
4. Geographic range: the total area in which an organism lives on the planet.
5. biotic: the living organisms in an ecosystem
6. abiotic: the nonliving factors in the ecosystem (the physical and chemical environment
7. Ecological niche: The role an organism occupies in the ecosystem. There are three basic niches.
8. Trophic level: the location of an organism in the food chain. Also called its ecological niche.
9. Producer: Are plants. They take a form of energy and use it to make carbohydrates and other large compounds out of inorganic compounds (carbon dioxide, water).
10. Autotrophs: are producers, plants or chemosynthetic bacteria
11. Decomposer: convert dead material back into smaller compounds, raw nutrients, to be reused by producers or other organisms in the environment.
12. Scavenger: An animal that eats dead animals.
13. Detritivore: An animal that eats detritus
14. Saprotroph: An organism that digests its food outside its body then takes it in. Ex. Fungus, molds. They are fit into the decomposer niche
15. Detritus: Any organic waste from animals and plants.
16. Heterotrophs: are consumers, usually animals that eat animals or plants
17. Consumer: Organism that eat producers or other consumers.
18. Primary consumer: A consumer that eats producers. A herbivore
19. Secondary consumer: A consumer that eats primary consumers. A carnivore
20. Tertiary consumer: A consumer that eats secondary consumers. A carnivore. Usually at the top of a food chain.
21. Herbivore: An animal that eats plants only
22. Carnivore: An animal that eats animal tissue only.
23. Omnivore: An animal that eats both plant and animal tissue on a regular basis.
24. food chain: A linear illustration of who eats whom in an ecosystem
25. Food web: a series of interlocking food chains that illustrates who eats whom in an ecosystem. This represents the transfer of energy and organic matter through the trophic levels in an ecosystem.
26. Biological magnification (bioamplification): The buildup of toxic chemicals in organisms as tissues containing the chemical move through the food chain. The toxic chemicals are absorbed by fatty tissue and stay in the body of the organism.
4. explain quantitatively the energy and matter exchange in aquatic and terrestrial ecosystems,
using models such as pyramids of energy, biomass and numbers.
Ecological pyramids: another type of illustration of the flow of energy, matter and numbers in an ecosystem.
Pyramid of numbers: Illustrates the total numbers of each organism in a food chain. The producer numbers are placed at the bottom while the top carnivore numbers are placed at the top of the pyramid.
Pyramid of biomass : Illustrates the total biomass of the total population of each organism in a food chain. The producer biomass is placed at the bottom while the top carnivore biomass is placed at the top of the pyramid.
Pyramid of energy: Illustrates the total energy in the population of the organism in each trophic level in a food chain. The producer energy is placed at the bottom while the top carnivore energy is placed at the top of the pyramid.
As energy flows through ecosystems, stored in the chemical bonds in the organic compounds that compose the cells and cell compounds of the organism, some energy is always lost as heat, used by the organism for body functions, or released in the waste produced as the organism lives its life. Therefore not all the energy an organism receives will be passed on to the next tropic level. The standard number used is 10%. Ten percent of the energy from one tropic level is used to support the next tropic level. This places a limit on the number of tropic levels in any given food chain or web. It also places a limit on the numbers of organism, and their biomass, at each tropic level. This can be illustrated in food chains or food webs, or in ecological pyramids. This also explains the shape of ecological pyramids. Their bases are very large, meaning a lot of energy, biomass, and numbers exist at the producer level, but as you go up the pyramid, to higher levels in the food chain, the available energy decreases with a corresponding decrease in biomass and numbers.
General Outcome 2: Students will explain the cycling of matter through the biosphere.
1. explain and summarize the biogeochemical cycling of carbon, oxygen, nitrogen and
phosphorus, and relate this to general reuse of all matter in the biosphere
2. explain water’s primary role in the biogeochemical cycles, using its chemical and physical
properties, i.e., universal solvent, hydrogen bonding.
3. explain that science and technology have both intended and unintended consequences for
humans and the environment
4. discuss the influence of human activities on the biogeochemical cycling of phosphorus,
sulphur, iron and nitrogen
Biogeochemical cycles
1. Biogeochemical cycles involve the cycling of matter. These include the carbon, water, nitrogen, and phosphorous cycles. The substances are all important in various life processes
2. Energy from the sun is the principle driving force within all these cycles
3. But just as energy is important to drive these cycles (a top down approach) decomposers are equally important to keep matter available to be recycled (a bottom up approach). Hence if either the energy source is deprived or the decomposers (bacteria, worms, and insects) are eliminated the biosphere would lose its steady state equilibrium, it would lose its balance, it could not continue. An example of this was witnessed in Biosphere II project.
The Water Cycle
Uses of water:
1. water makes up 70-99% the body mass of all living things
2. it is the major compound in living cells
3. needed for digestion, transport, cooling, location where reactions occur
Properties of water that make it essential for live:
1. Universal solvent: Water dissolves more substances on earth than any other liquid. It dissolves both gases and solids allowing water to carry gases and nutrients throughout multicelled organisms, making up the principle component of all circulatory systems.
2. high heat capacity: Water has high heat capacity. This means it hold heat very well. It takes a long time to heat up, but also takes a long time to cool down. Therefore water acts as an insulator from both cold and hot extremes.
3. Cohesive: water molecules stick together very well. This is due to the intermolecular bonding forces, hydrogen bonding, dipole-dipole, and London dispersion. This allows some organisms to “float” on top of water. This also allows water to be pulled in a continuous stream up xylem in plants from roots to leaves, the cohesion tension theory of water transport in plants.
4. Adhesive: water molecules also stick to other surfaces (due to hydrogen bonding). This allows water to act as a lubricant, protecting joint surfaces on all moveable joints in vertebrates and invertebrates. It also allows water to reduce friction between organs that can rub together (heart and lungs). It also allows water to stick to the xylem cells, holding it against gravity, allowing water to be pulled up from roots to leaves against the force of gravity.
5. Density: an anomalous property, when water freezes its density decreases therefore ice floats
Steps of the water cycle
1. Evaporation: solar energy converting liquid water to water vapor
2. Condensation: as water rises in the atmosphere it cools, converting from water vapor to liquid water or to snow or ice crystals in the atmosphere, forming clouds.
3. Precipitation: Water in clouds falling to the ground as rain, snow, sleet, hail.
4. Transpiration: water evaporating from the surface of leaves, through stomata, into the atmosphere
5. Runoff: excess water that flows off the surface of the land forming rivers and streams, flowing to lakes or ponds, and eventually to the oceans.
6. Percolation: The movement of water through the topsoil, through the ground, into the groundwater.
7. ground water: water stored in porous rock below the soil. It can form large bodies of water in porous rock called aquifers.
8. water table: The top surface of the ground water aquifer.
Unintended consequences of human interference = Acid Rain
The water cycle and acid rain
1.Acid rain is rainwater below the pH of 5.6
2. combustion of fossil fuels produces nitrogen and sulfur oxides
3. These compounds mix with water in the air forming nitric and sulfuric acid.
4. When these compounds fall to the ground they damage both living and nonliving things
5. acid rain leaches toxic metals from the soil which can be absorbed by plants and then the plants ingested by animals. These metals bioamplify in the food chain having serious effects on top carnivores.
6. acid rain damages living tissues in plants and inhibits enzymes, growth, and germination
7. it also damages steel, concrete, and marble statues and building exteriors.
8.it is fixed by scrubbers, adding lime to lakes, more efficient engines, reduced use of fossil fuels
The carbon cycle
Carbon is one of the essential elements in all living organisms. Because of its ability to form 4 chemical bonds with other elements it can make an almost infinite array of different compounds. Carbohydrates, fats, proteins, and vitamins are all composed of carbon atoms.
Steps in the carbon cycle
1. photosynthesis: carbon dioxide + water in chloroplasts with chlorophyll and sunlight produces oxygen and glucose
2. cellular respiration: oxygen + glucose in the mitochondria produces carbon dioxide and water, heat and ATP (cellular energy)
3. fossilization: a long geological process where dead plant and animal material is converted into hydrocarbon compounds (crude oil)
4. combustion: the addition of oxygen to hydrocarbons to produce carbon dioxide and water and heat
5. volcanic eruptions: release large amounts of carbon dioxide into the atmosphere
6. diffusion: the oceans cover 75% of the planet. Carbon dioxide gas in the atmosphere can diffuse into the oceans and well as diffuse out of the oceans. The overall extent of the effect of oceans on carbon dioxide in the atmosphere is not known. The oceans could act as a large‘sink’ holding large amounts of carbon dioxide gas, which may be released at a later period.
Unintended consequences of human interference = enhanced greenhouse effect
Precautionary principle: if the effects of human induced change would be very large, those responsible must prove that it will not do harm before proceeding.
The carbon cycle and the greenhouse effect
1. Carbon dioxide is produced during fossil fuel combustion, forest fires, decomposition, respiration, volcanoes, and deforestation reduces carbon dioxide consumption by plants (less plants).
2. Carbon dioxide allows light to pass through but traps reflected heat. This is the greenhouse effect
3. The greenhouse effect keeps the earth warm and allows life to exist. But too much carbon dioxide can increase global temp too fast. Global warming may also be influenced by solar cycles
4. The role of the oceans in storage and release of carbon dioxide is not known. Since the ocean covers 75% of the surface of the earth and has tremendous volume it could have a significant effect on carbon storage (increasing global temp would increase water/ocean temp and water holds less gas at warmer temp)
5. This can cause melting of glaciers and icecaps, increasing the level of the ocean, flooding coastal cities, increased storms, hurricanes, tornadoes, and shifts in global weather and climate
The nitrogen cycle
Nitrogen is an important element in proteins. Proteins are essential in all living cells and viruses. Proteins are used to make important compounds for living organisms, antibodies, hormones, enzymes. The major storage form of nitrogen is nitrogen gas in the atmosphere. Nitrates are usable form plants get there nitrogen in, plants can not use nitrogen gas in the atmosphere.
Steps in the nitrogen cycle
1. nitrogen fixation: performed by bacteria (nitrogen fixing bacteria) in the soil, they convert atmospheric nitrogen gas into nitrates which are usuable to plants. The most common bacteria that do this (Rhizobium) and found in root nodules of the legume (vegetable) family of plants.
2. denitrification: the reverse of nitrogen fixation. Bacteria in the soil convert nitrates to nitrogen gas
3. ammonification: the breakdown of organism waste products (proteins) into ammonia by bacteria
4. decomposition: the breakdown of waste products into other compounds by bacteria and protozoa
5. assimilation/protein synthesis: the uptake of nutrients from the soil and encorporation of those into the organisms cells
6. lightning: converts atmospheric nitrogen into nitrates
7. eutrophication: the filling in of a lake by organic matter and silt. This usually results in an increase in plant and animal population growth with results in increased oxygen consumption from the water and may lead to death of most organisms in the lake due to loss of oxygen.
Phosphorous cycle
Phosphorous is used in cell membranes and for energy storage in cells (ATP)
Steps in the phosphorous cycle.
1. weathering and erosion: these processes remove phosphates from rocks and soil, releasing them into the atmosphere, streams and rivers.
2. Runoff: excess water from rainfall leaches phosphates from the soil or rocks carrying the phosphates to ponds, lakes, and oceans.
3. Decomposition: the breakdown of waste products or dead bodies into other compounds by bacteria and protozoa
4. Assimilation: the uptake of nutrients from the soil and encorporation of those into the organisms cells
5. Eutrophication: the filling in of a lake by organic matter and silt. This usually results in increase animal population growth with results in increased oxygen consumption from the water and may lead to death of all organisms in the lake due to loss of oxygen. Excess phosphates in runoff from fields or in the water from sewage and treated water from cities and towns enhance eutrophication.
5. discuss the use of water by society, the impact such use has on water quality and
quantity in ecosystems, and the need for water purification and conservation
Other than the air we breath (oxygen gas is all we use from the air) water is the next most important, essential substance all living things, and human societies, need to survive. Urban expansion (called urban sprall) has filled in many wetland areas , altered streams, and added wastewater and urban pollution to rivers and streams. Human consumption and cleaning, industrial mining, oil and gas, and agricultural use (irrigation) consumes tremendous amounts of water. All these add to the “drain” on freshwater supplies in Alberta and Canada. This often results in water restrictions at different times of the year when water shortages develop, when the production of clean water by water treatment plants falls below the consumption by humans. Or in rural settings if not enough rainfall occurs and the water table falls and wells run dry. Or fish spawning and habitat are affected by mining and oil and gas use and wastewater.
With increased human demand for water and increased desire to protect freshwater and saltwater ecosystems, there is an increased need for faster water purification and water conservation.
6. analyze the relationship between heavy metals released into the environment and
matter exchange in natural food chains/webs, and the impact of this relationship on the
quality of life.
Heavy Metals in the Food Chain/Web
Mercury
Sources: mining
Effects: behavior disorders
Lead
Sources: old paint
Effects: damages nerve cells, learning disabilities, anemia,
General Outcome 3: Students will explain the balance of energy and matter exchange in the biosphere, as an open system, and how this maintains equilibrium.
1. explain the interrelationship of energy, matter and ecosystem productivity (biomass
production
Primary Productivity of Ecosystems
Increased solar energy leads to increased photosynthesis measured as increased primary productivity measured as increased biomass of the ecosystem.
Primary productivity can be determined by measuring the growth of plants in an area. The total plant material in a defined area can be removed, dried, and weighed and then compared between different ecosystems to determine which is more productive, or which receives more energy. (Quadrat sampling)
Rainforest vs desert
Rainforest has tremendous productivity. It receives sunlight 12 hours per day for 365 days of the year. Combined with large amounts of precipitation and fast decomposition, plants grow very well here. In contrast deserts are typified by low productivity due to a lack of precipitation.
Intertidal zone vs deep sea
Intertidal zone has high productivity compared to deep sea primarily because of a lack of sunlight in the deep sea and a lack of producers.
2. explain how the equilibrium between gas exchanges in photosynthesis and cellular
respiration influences atmospheric composition
The balance that exists between photosynthesis and cell respiration has a significant effect on the concentration of oxygen and carbon dioxide in the atmosphere. Photosynthesis uses carbon dioxide in the atmosphere and produces oxygen while cell respiration produces carbon dioxide and uses oxygen. If not enough photosynthesis happens (due to deforestation or altering the ph of the oceans) carbon dioxide levels can increase.
3. describe the geological evidence (stromatolites) and scientific explanations for change in
atmospheric composition, with respect to O2 and CO2, from anoxic conditions to the present
and the significance to current biosphere equilibrium.
Evidence for Climate Change
Stromatolites: are fossils found in sedimentary rock. These tell us that the current temperate climate regions of the world were once tropical because we find fossils of tropical plants and animals in these regions.
Current trends indicate carbon dioxide emissions are increasing, increasing atmospheric carbon dioxide, which enhances the greenhouse effect. This could lead to a warming trend in the earths climate with corresponding changes in global ecosystems.
General Outcome 4: Students will explain that the biosphere is composed of ecosystems, each with distinctive biotic and abiotic characteristics.
1. define and explain the interrelationship among species, population, community and
ecosystem
Species: members of a population that can reproduce together to produce fertile offspring
Population: members of the same species that are in a defined area at a specific time
Community: populations of different organisms that exist in the same area. The structure of a community is measured and described in terms of species composition and species diversity.
Ecosystem: the interaction of the biotic and abiotic components in a characteristic environment
2. explain how a terrestrial and an aquatic ecosystem supports a diversity of organisms through
a variety of habitats and niches
The biosphere contains many types of ecosystems. The can be divided into terrestrial (land) and aquatic (water) ecosystems.
Terrestrial Ecosystem niches: Vertical stratification in forests
Canopy: The uppermost layer of the forest where most of the leaves on the trees are found
Sub-canopy:The region below the canopy composed mostly of tree trunks with no leaves
Forest floor: The top surface of the ground of the forest
Soil: The dirt below the forest floor
Types of terrestrial ecosystems:
Tundra:
Boreal forest:
Temperate deciduous forest:
Grassland:
Tropical Rain Forest:
Desert:
3. identify biotic and abiotic characteristics and explain their influence in an aquatic and a
terrestrial ecosystem in a local region
Aquatic ecosystems (marine)
Marine ecosystems can be further divided into freshwater (lakes, rivers, ponds) and saltwater (oceans/seas)
A. Freshwater ecosystems.
Lakes and ponds:
a) Littoral zone: the shallow water zone around the perimeter of a lake or pond. Contains submergent vegetation.
b) Limnetic zone: the open water zone that light penetrates through. May contain vegetation floating on top but no vegetation rooted from the bottom growing up through it.
c) Profundal zone: the deep water zone where no light can reach. The bottom region of deep lakes.
d) Benthic zone: the bottom layer of the entire pond or lake. Consists of mud and plant and animal waste. This is where decomposition occurs.
e) Plankton: any small free floating organism suspended in the water
f) Zooplankton: The plankton that are animals, are herbivorous or carnivorous
g) Phytoplankton: The plankton that are plants, they undergo photosynthesis and are the major producers in almost every aquatic ecosystem.
4. explain how limiting factors influence organism distribution and range
Limiting factors (how they influence range and distribution)
Examples: water availability, temperature, food availability, disease, predators
Increases in these factors restrict the range and distribution of populations. Organisms only exist within the range of tolerance to their resources that support them.
5. explain the fundamental principles of taxonomy, i.e., domains, kingdoms and binomial
nomenclature.
Taxonomy –is the process of classifying or organizing organisms into groups based on shared characteristics. It uses a system of rules to group or classify organisms.
Taxonomy was highly refined by Carl Linnaeus. He developed the system of binomial nomenclature. This means that every organism can be identified using two names.
The rules for binomial nomenclature are as follows:
• The first name is the genus name
• The genus name is given an upper-case first letter
• The second name is the species name
• The species name is given a lower case first letter
• Italics are used when the name is printed
• The name is underlined if it is handwritten
Domain: A taxonomic category above the kingdom. All living things are divided into one of three domains: Archaea, Bacteria, and Eukarya. Archaea and Bacteria are both prokaryotic while Eukarya are eukaryotic.
Modern taxonomy divides all eukaryotic organisms on the planet in to five kingdoms, each with 8 other subdivisions, the last two always being the genus and species. The 7 levels of classification are: kingdom, phylum, class, order, family, genus, and species. Species are defined as a group of organisms that can reproduce together to produce fertile offspring.
Phylogenetic trees and cladograms are graphical representations (models) of evolutionary history that can be tested.
Clade- a group (large or small, recent-extant or past-extinct) of organisms that evolved from a common ancestor
Cladistics-a method of classifying living organisms based on the construction and analysis of cladograms
Cladogram- a tree/bush/branching diagram that illustrates the groups of organisms with common ancestors. It is based on analysis of biochemical differences (amino acids of the same protein, or DNA differences) between species, not the traditional morphological differences.
Uses of cladograms-primarily used to determine evolutionary origins of species.
a. Phylogenetic trees and cladograms can represent traits that are either derived or
lost due to evolution.
• Number of heart chambers in animals
• Opposable thumbs
• Absence of legs in some sea mammals
b. Phylogenetic trees and cladograms illustrate speciation that has occurred, in that relatedness of any two groups on the tree is shown by how recently two groups had a common ancestor.
c. Phylogenetic trees and cladograms can be constructed from morphological similarities of living or fossil species, and from DNA and protein sequence similarities, by employing computer programs that have sophisticated ways of measuring and representing relatedness among organisms.
d. Phylogenetic trees and cladograms are dynamic (i.e., phylogenetic trees and cladograms are constantly being revised), based on the biological data used, new mathematical and computational ideas, and current and emerging knowledge.
General Outcome 5: Students will explain the mechanisms involved in the change of populations over time.
1. Describe modern evolutionary theories, i.e., punctuated equilibrium versus gradualism.
Evolutionary Theory: A Historical Development
1. Greeks: Aristotle, Plato (400-300B.C.)
There are ideal forms, meaning organisms can change
2. Renaissance: Davinci, Galileo, Newton (1400-1600)
The earth is not the centre of the universe
3. George Cuvier: Started the study of fossils (paleontology)
Reconstructed ancient animals from fossils
These animals were not alive today but must
Have lived in the past.
4. Lyell Hutton: Used radiometric techniques to find the age of the Earth. Found the earth is 4-5 billion years old
5. Jean Lamark: (1800’s) Inheritance of Aquired Characteristics.
Proposed one of the first mechanism for how evolution occurs.
6. Darwin and Wallace: (1800’s) Developed the theory of Natural Selection.
7. Modern theories: Neodarwinism
Punctuated Equilibrium vs gradualism
Origin of prokaryotic and eukaryotic cells
Endosymbiotic theory
2.explain that variability in a species results from heritable mutations and that some mutations
may have selective advantage(s)
The importance of variation in populations
Variation allows for the survival of a population should the environment change in a way harmful to most of the members. Variations breeds stability of the population. If a population has no variation and the environment changes in such a way as to be harmful to the population the change will cause increased mortality causing decline in population numbers and possible extinction of the population and species. If variations exist, one such variation may prove to be an adaptation to this change in environment and those members with the variation /adaptation will survive/live longer reproduce more and pass on their characteristics to a greater percentage than those members that do not have the adaptation (they have better reproductive fitness)
There are four types:
Inherited variation- those characteristics passed on through the genes carried on chromosomes in the sperm or egg cell. Ex. Blood types (A, B, AB, O, eye color, normal and abnormal lactose enzyme)
Acquired variation-those characteristics received from the environment and are not passed on to future offspring; do not affect genes in chromosomes of the sperm or egg cells. Ex. Cuts, scars, tan lines, dying your hair, amputation of a finger.
Continuous variation- traits that show graduation of small differences. Ex. Height in humans
Discontinuous variation – traits that do not show graduation of small differences. Ex. Comb shape in chickens. Rose, single, pea, and walnut, there are not intermediates.
Environmental influence
Environmental factors influence many traits both directly and indirectly. Ex human height and weight, flower color based on soil pH, UV light and skin color in humans
An organism’s adaptation to the local environment reflects a flexible response of its genome. Ex. Darker fur in cooler regions of the body in certain mammal species, darker human skin color in tropical areas.
The level of variation in a population affects population dynamics
A population’s ability to respond to changes in the environment is affect by genetic diversity. Species and populations with little genetic diversity are at risk for extinction. (Prairie chickens, cheetah, koala bear)
Genetic diversity allows individuals in a population to respond differently to the same changes in environmental conditions. (Variation in immune response to the same pathogen)
The diversity of species within an ecosystem may influence the stability of the ecosystem
Natural and artificial ecosystems with fewer component parts and with little diversity among the parts are often less resilient to changes in the environment.
Keystone species, producers, and essential abiotic and biotic factors contribute to maintaining the diversity of an ecosystem. The effects of keystone species on the ecosystem are disproportionate relative to their abundance in the ecosystem, and when they are removed from the ecosystem, the ecosystem often collapses.
Mutations
Mutations are changes in the genetic information of a cell. Only mutations in the chromosomes of sperm or egg cells are passed on to future generations. Mutations are caused by chemicals in the environment, heat, radiation, and some viruses.
Adaptations and Adaptive significance
Characteristics that make an organism better suited to live and reproduce in their environment
Ex. Thick fur in polar bears, excellent night vision in owls.
Adaptive significance is the importance of an adaptation to an organism in its environment. What purpose does this characteristic serve the organism?
3. discuss the significance of sexual reproduction to individual variation in populations and to
the process of evolution
Sexual reproduction allows for the mixture of characteristics from two parents. Both parents contribute half of their genetic information to each offspring. The characteristics the offspring express are determined by the combinations of genes they inherit from their parents. This produces variation in all offspring.
Evolutionary fitness is measured by reproductive success.
4. compare Lamarckian and Darwinian explanations of evolutionary change
Inheritance of Acquired Characteristics
Lamark’s theory, also called the law of use and disuse. According to this theory an organism can change its body characteristics during its lifetime. That by using a certain part of its body this part would slowly change to be better adapted to the environment, through continual use. Conversely, that if a body part were not used over the lifetime of the organism it would slowly lose its function, slowly disappear. Also, that the acquired (modified) characteristic would then be passed on in its modified form to its offspring.
Weaknesses: The environment does not caused directional mutations: the environment does not cause mutations in genes of characteristics that are used more than genes that are not used for that specific behavior or adaptation.
Darwin and Wallace’s theory of natural selection
Darwin and Wallace developed the same explanation simultaneously and independently. It has five specific points:
1. overproduction: all populations have the capacity to produce more offspring than what the environment can sustain.
2. Variation: within natural populations differences always exist between individuals.
3. Struggle for existence: competition exists between and within species for food, water, shelter, mates, space.
4. Survival of the fittest (natural selection) Those members that have the best adaptations to the environment will live longer and reproduce more (have greater reproductive fitness), passing on their characteristics in the population more than other members that do not have those adaptations. ( this does not exclude cooperation, the adaptation could be anything that increases the chance of survival and reproduction)
5. Origin of new species: Speciation- the process of forming new species. This occurs through geographic isolation. Groups of individuals of the same species become separated from each other, and therefore cannot reproduce. Over time small changes occur in each population (microevolution) until eventually the groups are so different they cannot reproduce to produce fertile offspring. At this point a new species has been created (macroevolution). Evolutionary fitness is measured by reproductive success.
a. According to Darwin’s theory of natural selection, competition for limited resources results in differential survival. Individuals with more favorable phenotypes are more likely to survive and produce more offspring, thus passing traits to subsequent generations.
b. Evolutionary fitness is measured by reproductive success.
c. Genetic variation and mutation play roles in natural selection. A diverse gene pool is important for the survival of a species in a changing environment.
d. Environments can be more or less stable or fluctuating, and this affects evolutionary rate and direction; different genetic variations can be selected in each generation.
e. An adaptation is a genetic variation that is favored by selection and is manifested as a trait that provides an advantage to an organism in a particular environment.
f. In addition to natural selection, chance and random events can influence the evolutionary process, especially for small populations.
Environments change and act as selective mechanisms on populations. (ex. Peppered moth, antibiotic resistance)
Phenotypic variations are not directed by the environment but occur through random changes in the DNA (mutations) and through new gene combinations (sexual reproduction)
Some phenotypic variations significantly increase or decrease fitness of the organism and the population. (DDT resistance in insects, sickle cell anemia in humans)
Humans can also impact variation in organism (artificial selection, overuse of antibiotics)
Behavior
a. Individuals can act on information and communicate it to others.
1. Innate behaviors are behaviors that are inherited.
2. Learning occurs through interactions with the environment and other organisms.
b. Responses to information and communication of information are vital to natural selection.
1. In phototropism in plants, changes in the light source lead to differential growth, resulting in maximum exposure of leaves to light for photosynthesis.
2. In photoperiodism in plants, changes in the length of night regulate flowering and preparation for winter.
3. Behaviors in animals are triggered by environmental cues and are vital to reproduction, natural selection and survival.• Hibernation• Estivation• Migration• Courtship
4. Cooperative behavior within or between populations contributes to the survival of the populations.
• Availability of resources leading to fruiting body formation in fungi and certain types of bacteria
• Niche and resource partitioning
• Mutualistic relationships (lichens; bacteria in digestive tracts of animals; mycorrhizae)
• Biology of pollination
5. summarize and describe lines of evidence to support the evolution of modern species from
ancestral forms
Evidence for Evolution
a. Scientific evidence of biological evolution uses information from geographical, geological, physical, chemical and mathematical applications.
b. Molecular, morphological and genetic information of existing and extinct organisms add to our understanding of evolution.
Fossils- The remains (bones, bodies, body material) impressions and traces of organisms from past geological ages. They provide a record (pictures) of past life. Many fossils represent species that have become extinct. They indicate that the earth is very old and that life forms change over time. Fossils form when 1) the organism is buried quickly; 2) it decays leaving spaces; 3) the spaces are filled with silt and minerals over the years. This results in bones or materials that have become rock. If the organism decays it may leave behind a fossilized imprint in the rock that forms.
Also, the rocks tell of different periods in geologic history that are characterized by different life forms and dominated by different life forms. This is called the geologic time scale
Microevolution- the accumulation of small changes in the characteristics of a population. Through natural selection this fits organisms to their environment. It does not directly produce new species. Speciation occurs through macroevolution. Peppered Moths population color changes and antibiotic resistance in bacteria are an example of microevolutionary change. Both these changes happened in response to environmental changes.
Comparative Anatomy (morphology)- organisms with similar structures implies a common ancestor
a. analagous structures- are similar in function and appearance but not in origin. The wing of an insect and the wing of a bird. This also indicates that similar adaptations develop (evolve) under similar environmental pressures. This is called convergent evolution, the development of similar forms from unrelated species due to adaptation to similar environment.(ex. ocean mammals and fish have the same body shape and adaptations but both evolved from different ancestors)
b. homologous structures- have similar origin but different uses in different species. The front flipper of a dolphin and the forelimb of a dog. This indicates they share common ancestory. Their body parts are the same but over time have been modified (adapted through mutations, natural selection, and environmental pressures) to be used in different environments for similar or different purposes. This is called divergent evolution.
c. Vestigial structures-are remnants of functional structures in other organisms. These can be compared to fossils or other living organisms.
Biochemical- All organisms have DNA. This is the molecule that makes up the chromosomes and carries the instructions to make all parts of the organism. The DNA of every organism is made of the same parts. The sequence in the DNA makes different organisms different. Similar organisms have more similar DNA, this indicates they have a more common ancestor than compared with organisms that have more dissimilar DNA. The more different the DNA of two organisms the further in the past was their common ancestor (evolutionary clock). Changes in DNA (mutations) are caused by temperature, radiation, chemicals, and by spontaneous means. An extension on this concept is the evolutionary clock theory which states that the greater the difference in the amino acid sequence of the same protein in different organisms the further back in time was their common ancestor.
Other chemical evidence comes from comparing the same chemical in different organisms. (insulin)
The more similar the DNA and chemicals (proteins-hormones, enzymes) in different species, the more recent was their common ancestor. This information can be used to determine ancestry and build cladograms.
Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today.
a. Structural and functional evidence supports the relatedness of all domains.
1. DNA and RNA are carriers of genetic information through transcription, translation and replication.
2. Major features of the genetic code are shared by all modern living systems.
3. Metabolic pathways are conserved across all currently recognized domains.
b. Structural evidence supports the relatedness of all eukaryotes.
• Cytoskeleton (a network of structural proteins that facilitate cell movement, morphological integrity and organelle transport)
• Membrane-bound organelles (mitochondria and/or chloroplasts)
• Linear chromosomes
• Endomembrane systems, including the nuclear envelop.
Biogeographical distributions- Similar species are found in similar habitats in different parts of the world. Natural selection molds an organism to its environment, since land masses were once together these organisms at one time were part of one population that became isolated as the continents split apart. Consequently these similar species have unique differences. Example 1: big flightless birds—rhea, emu, ostrich, 2: placental marsupial, and monotreme mammals. All mammals have hair, internal fertilization, warm blooded, and breast feed. The placental mammals the fetus develops in the uterus, are found all over the world except Australia. The marsupials the fetus develops in a external pouch, they are found mostly in Australia, there is one north American marsupial, the opossum. The monotremes lay eggs and incubate. They are only found in Australia, New Guinea, and Tazmania.
5. explain speciation and the conditions required for this process
Speciation and extinction have occurred throughout the Earth’s history.
a. Speciation rates can vary, especially when adaptive radiation occurs when new habitats become available.
b. Species extinction rates are rapid at times of ecological stress.
• Five major extinctions
• Human impact on ecosystems and species extinction rates
Speciation may occur when two populations become reproductively isolated from each other.
a. Speciation results in diversity of life forms. Species can be physically separated by a geographic barrier such as an ocean or a mountain range, or various pre-and post-zygotic mechanisms can maintain reproductive isolation and prevent gene flow.
b. New species arise from reproductive isolation over time, which can involve scales of hundreds of thousands or even millions of years, or speciation can occur rapidly through mechanisms such as polyploidy in plants.
Types of speciation
Allopatric speciation (in different geographic areas)—caused by geographic isolation. Members of a population isolate themselves from the parent population and over long periods of time through the accumulation of mutations that survive because of living in a different environment (acquiring new adaptations) they develop different features and eventually will not reproduce with the parent population. This takes thousands of years and the right environmental conditions
Sympatric speciation(in the same geographic area)—caused by mutations that cause changes in location populations that prevent them from reproducing. When two or more populations of the same species that live in the same area but develop mutations that prevent them from reproducing together. This is also called adaptive radiation
Populations of organisms continue to evolve.
a. Scientific evidence supports the idea that evolution has occurred in all species.
b. Scientific evidence supports the idea that evolution continues to occur.
• Chemical resistance (mutations for resistance to antibiotics, pesticides, herbicides or chemotherapy drugs occur in the absence of the chemical)
• Emergent diseases
• Observed directional phenotypic change in a population (Grants’ observations of Darwin’s finches in the Galapagos)
• A eukaryotic example that describes evolution of a structure or process such as heart chambers, limbs, the brain and the immune system
The pace of evolution: Two theories explain how fast speciation occurs.
1. Gradualism, slow progressive change from one species into another (s).
2. Punctuated equilibrium, fast changes (geologically speaking) followed by periods of stability.
3. The fossil record shows evidence for both theories.
6.The origin of living systems is explained by natural processes
There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence.
a. Scientific evidence supports the various models.
1. Primitive Earth provided inorganic precursors from which organic molecules could have been synthesized due to the presence of available free energy and the absence of a significant quantity of oxygen.
2. In turn, these molecules served as monomers or building blocks for the formation of more complex molecules, including amino acids and nucleotides.
3. The joining of these monomers produced polymers with the ability to replicate, store and transfer information.
4. These complex reaction sets could have occurred in solution (organic soup model) or as reactions on solid reactive surfaces.
5. The RNA World hypothesis proposes that RNA could have been the earliest genetic material.
Scientific evidence from many different disciplines supports models of the origin of life.
a. Geological evidence provides support for models of the origin of life on Earth.
1. The Earth formed approximately 4.6 billion years ago (bya), and the environment was too hostile for life until 3.9 bya, while the earliest fossil evidence for life dates to 3.5 bya. Taken together, this evidence provides a plausible range of dates when the origin of life could have occurred.
2. Chemical experiments have shown that it is possible to form complex organic molecules from inorganic molecules in the absence of life.
b. Molecular and genetic evidence from extant and extinct organisms indicates that all organisms on Earth share a common ancestral origin of life.
1. Scientific evidence includes molecular building blocks that are common to all life forms.
2. Scientific evidence includes a common genetic code.
Conditions of prebiotic earth
No oxygen, methane gas, nitrogen gas, water vapor, ammonia, hydrogen gas, lightning
Spontaneous origin of life on Earth
1. nonliving synthesis of organic molecules (Miller-Urey experiment)
2. assembly of these molecules into polymers
3. the origin of self-replicating molecules making inheritance possible
4. packaging these molecules into membranes with an internal chemistry different from their surroundings
Formation of the first organic compounds
1. The Miller-Urey experiments demonstrate one way organic compounds may have first formed.
2. Organic compounds include amino acids, then proteins, carbohydrates, fats, and DNA
3. In this experiment the elements present in the pre-biotic earth atmosphere were placed in a reaction flask and exposed the sparks for one week. Amino acids were produced
4. With more carbon dioxide in the flask other organic compounds were produced.
Polymerization reactions
1. Many organic compounds are made by putting many of the same parts together forming long chains of the same part. This is called polymerization.
Optional: Human Evolution
Humans share many features similar to other tree dwelling primates including: opposable thumb, longer fingers, mobile arms with very flexible shoulder joints, stereoscopic vision, and a ventral facing skull.
Biochemical evidence (analysis of mitochondrial DNA) indicates there is more variation in mitochondrial DNA in Africa than in any other country. This indicates that the all humans originated from a population (s) of Homonids in Africa. The more variation in DNA the longer it has been around. Newer DNA will have fewer mutations (variations)
Ardipithecus ramidus
Australopithecus afarensis-4-2.8 m.y.a. (lucy) partially bipedal
A.africanus – 3-2 m.y.a.
Homo habilis- - 2-1 m.y.a. complete bipedal
H. erectus – 1,000,00 – 500,000 y.a.
H. neanderthalensis – 250,000 – 100,000 y.a.
H. sapiens – 100,000 to present
As climates grew cooler and drier, forests were replaced by savannas. Gradually, hominids climbed trees with decreasing frequency. As they were bipedal, this freed their hands to carry tools. Also, the environment of early Homo species was so diverse, they needed the larger brain to deal with all the different challenges. So individuals with the conventional smaller brains were at a disadvantage and eventually disappeared. Cooler temperatures also selected for adaptations to cold. Neanderthals had short thick bodies, which retained heat better than the longer, slimmer shape of H. erectus. A better brain also allowed them manipulate their environment (furs, fire, shelter, domesticated animals) increasing their survival in the cooler climates of northern Europe. There is also a positive correlation between increased brain size and a change in diet during hominid evolution (a bigger brain uses more energy, a more energy rich diet was needed to maintain the brain from-- vegetarian to meat). Learning to use fire to cook meat saves energy (chewing raw meat uses more energy that cooked meat).
From fossils (Lucy) we know that bipedalism came before increased brain size. Once our ancestors walked upright their hands were freed from walking. The hands could now be used for other functions, such as tool making and communication, or carrying food, water, children, and weapons over longer distances.
Neoteny: maintaining juvenile/youth characteristics in the adult (flat faces, little body hair). This is seen in humans but not in other primates, making us different from the other primates. This suggests that our development, maturation, has slowed down to prolong childhood and possibly gives us more time to learn from the environment (we have a brain that can comprend it better than other primates).
Modern humans are anatomically very similar to H.erectus. Its body was very similar to H.sapiens but its skull was different (heavier). H.erectus is thought to have developed in northern Africa about 1.5 million ;Africa and then spread to different parts of the world and developed different regional features (caucasian, asian, hispanic, native north american, India etc.). Several of these different hominid groups may have existed at the same time and competed with each other for resources.
The oldest tools found are 2.6 million years old. The use of tools coincided with the increase in brain size. H. habilis is known to have used simple tools, rocks chipped to a sharp edge. H. erectus used much more sophisticated tools such as a hand axe. Neanderthals may have had a religion. They buried their dead with flowers and tools, suggesting that they believed in an afterlife. Cro Magnon (modern man) painted drawings of animals on the walls of their caves.
Some scientists believe that H. neanderthalensis is a subspecies of H.sapiens, that both are the same species but that H neanderthalensis is an archaic form of modern humans (not like a different race) They are believed to have both existed at the same time, but that H. sapiens outcompeted H. neaderthalaensis
Neanderthal man may also have had the anatomy that allowed speech. They also hunted in groups, taking on large and dangerous animals which required excellent communication.
Genetic evolution involves the change of genetic material, which is subsequently passed on. The change is random and whether the change is an improvement is dictated by the environment.
Cultural evolution is the accumulation of useful skills and knowledge, and the discarding of harmful practices, passed down through thousands of human generations. It is based on the fact that we have elaborate language skills. Using language, accumulated experience can be passed from one generation to another.
Reasons for incompleteness of fossil record and resulting uncertainties about human evolution.
Not all geologic time periods were proper for fossil formation.
Soft bodied animals decompose fast so they do not produce fossils.
The larger the population, or the longer it was around, the more likely a fossil will be produced, thus small populations or short lived species rarely leave fossils.
Consequently for many species science is not totally certain of their origins. All that is present are theories supported by evidence (fossils, biochemical, biogeographical, etc.)
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