Download Final Review Answers BIOCHEMISTRY Chapter 3 Water and the

Final Review Answers
BIOCHEMISTRY
Chapter 3 Water and the Fitness of the Environment
1. The slightly negative regions of one molecule are attracted to the slightly positive regions of
nearby molecules, forming a hydrogen bond.
2. Expansion upon freezing causes water to be less dense than liquid water.
3. Transport of water and dissolved nutrients in a plant.
4. Hydrogen bonds repel air molecules creating a skin between the water and the air.
5. By absorbing heat from air that is warmer and releasing the stored heat to air that is cooler.
6. Heat depends in part on the matter’s volume, while temperature is the average kinetic energy
of molecules, regardless of volume.
7. Water has a high specific heat because of the hydrogen bonds acting on the molecules. These
hydrogen bonds can "store" thermal energy, and this allows water to absorb or release a lot of
heat without a large change in temperature.
8. Water's cohesive behavior, its ability to moderate temperature, its expansion upon freezing, and
its versatility as a solvent
9. Hydrogen bonds form, break and reform. Liquid water is denser than the solid
10. Clinging to walls of the cell
11. Can absorb or release a large amount of heat with only slight change in own temp
12. Heat passes from warmer to the cooler until the two are the same temperature
13. Large body of water can absorb and store a huge amount of heat from the sun in the daytime
and during summer while warming up only a few degrees - at night and during winter, the
gradually cooling water can warm the air
14. Presence of sulfur oxides and nitrogen oxides in the atmosphere that react with water to form
strong acids
15. Accepting hydrogen ions from the solution when they are in excess and donating hydrogen ions
to the solution when they have been depleted
16. Can damage life in lakes and streams, washes away calcium and magnesium ions
17. Water’s high heat of vaporization moderates climate. Much of the sun’s heat absorbed by
tropical oceans is used for the evaporation of surface water. As moist tropical air moves to the
poles, water vapor condenses to form rain, releasing heat.
18. Water is an effective solvent because it readily forms hydrogen bonds with charged and polar
covalent molecules
19. They form hydrogen bonds with water.
20. Their molecules are too large.
21. Vaporization occurs when a molecule moves fast enough to overcome the attraction of other
molecules in the liquid
22. Much of the energy is used to disrupt hydrogen bonds, not speed up the movement of water
molecules.
23. Heat must be absorbed to break hydrogen bonds and heat must be released to form hydrogen
bonds.
24. The heat of vaporization is high because hydrogen bonds must be broken before a water
molecule can evaporate from the liquid.
25. Living things are made of primarily water, so they resist changes in temperature better than
they would if composed of a liquid with a lower specific heat.
Chapter 5 Macromolecules
1) Structure: composed of atoms of carbon, hydrogen and oxygen in a ratio of 1:2:1.
Function: Short-term energy storage and structural support in cells (such as cellulose in cell
wall).
2) Structure: structures vary but they all possess large number of C - H bonds which make them
non-polar.
Function: energy storage, also function as structural components in the cell (phospholipid bilayer of cell membranes).
3) Structure: amino acids joined by dehydration synthesis that make up chains which are hundreds
of amino acids long.
4) Structure: made of nucleotides (nitrogenous base: pyrimidine or purine, 5 carbon ribose sugar,
phosphate group). Double helix.
Function: Serve as information-carrying molecules or, in the case of some RNA molecules,
catalysts.
5) Caused by the breaking of hydrogen bonds within enzyme structure. High/low temperatures,
strong acidity or alkalinity, and salinity.
6) Carbon, hydrogen, oxygen, nitrogen, phosphorus.
7) Carbon, hydrogen, oxygen
8) The double bond gives unsaturated fatty acids a bend in the methylene chain. Have as many
hydrogen bonded to their carbons as possible allowing no space for fluidity.
9) Monomers make up polymers and polymers make up macromolecules.
10) Molecule is broken down into two parts by the addition of H2O. One part of the parent
molecule gains a hydrogen ion (H + ) from the H2O. The other halve takes the remaining
hydroxyl group (OH − ).
11) 2 monomers joined by H2O. One monomer has a hydroxyl group on one end (OH) and the other
has hydrogen (H) on the end facing the other monomer. When OH and H are adjacent to each
other, H2O forms, and comes out as a product.
12) Hydrophilic heads are polar (bond shared unequally) so they are attracted to H2O which is also
polar. Hydrophobic tails are non-polar so they are repelled from water (no difference in
electronegativity).
13) Enzymes are catalysts. Catalyst is a substance that has the ability to increase the rate of a
chemical reaction, and is not changed or destroyed by the chemical reaction that it accelerates.
14) Primary, secondary, tertiary, quaternary.
15) Composed of an amino group, R (variable group), and an OH – hydroxyl group.
16) Composed of nitrogenous base: pyrimidine or purine, 5 carbon ribose sugar, phosphate group.
17)
18)
19)
20)
21)
22)
23)
24)
25)
20 types of amino acids differ by the composition of the R-group.
Purines: A,G
Pyrimidines: C,T,U
Adenine, Guanine, Cytosine, Thymine, Uracil
Structure: Composed of 3 fatty acids bonded to a glycerol.
Function: Store energy (fatty acids contain most of the energy).
Isomers are molecules with identical formulas but different structures.
Monosaccharides. Glucose, fructose, galactose.
Amino acids. (Any of the 20 main amino acids)
Nucleotides. DNA and RNA.
Capable of forming 4 bonds.
Chapter 6 Metabolism
1. Substrate.
2. Energy coupling, ATP.
3. Mechanical work: beating of cilia, contraction of muscle cells, and movement of chromosomes
during cellular reproduction. Transport work: the pumping of substances across cell membranes
against the direction of spontaneous movement. Chemical work: pushing of endergonic reactions
that would not occur spontaneously, such as the synthesis of polymers from monomers.
4. Energy can be transferred and transformed, but it cannot be destroyed. Thermodynamics is the
study of the energy transformations that occur in a collection of matter.
5. Every energy transfer or transformation increases entropy of the universe. Entropy is a measure of
disorder or randomness.
6. Anabolic, consume, catabolic, release.
7. The totality of an organism’s chemical reactions.
8. Free energy is the portion of a system’s energy that can perform work when temperature is uniform
throughout the system (e.g. In a living cell).
9. A competitive inhibitor mimics the substance and competes for the active site, a noncompetitive
inhibitor binds to the enzyme at a location away from the active site, but alters the conformation of
the enzyme so that the active site is no longer fully functional.
10. Cofactor.
11. Temperature, pH.
12. Feedback Inhibition.
13. Induced fit is the slight change in shape of the active site of an enzyme as it embraces its substrate.
14. Allosteric enzyme, allosteric.
15. Catalyst, enzyme.
16. Free energy of Activation, Activation energy (or vice versa)
17. Active site.
18. Kinetic energy, potential energy.
19. The study of how organisms manage their energy resources.
20. The system is the matter under study. The surroundings are everything outside the system, the rest
of the universe.
21. More, less, greater, less, more, less.
22. Release, gain.
23. The system’s total energy, its entropy.
24. A cell can maintain disequilibrium because it is an open system. Constant flow of materials in and
out of the cell keeps the metabolic pathways from ever reaching equilibrium and the cell continues
to do work throughout its life.
25. Sunlight
CELLS
Chapter 7 Cells
1. A—Cell walls exist in plant cells and prokaryotic cells, but not animal cells. They function to
shape and protect cells.
2. D—The lysosome acts like the stomach of the cell. It contains enzymes that break down
proteins, lipids, nucleic acids, and carbohydrates. Absence of these enzymes can lead to storage
disorders such as Tay-Sachs disease.
3. B—The mitochondrion is the power plant of the cell. This organelle specializes in the production
of ATP and hosts the Krebs cycle and oxidative phosphorylation.
4. C—The ribosome is an organelle made in the nucleolus that serves as the host for protein
synthesis in the cell. It is found in both prokaryotes and eukaryotes.
5. D—The fluid mosaic model says that proteins can extend all the way through the phospholipid
bi-layer of the membrane, and that these proteins are of various sizes and lengths.
6. B—Answer choice B is the definition of active transport, which requires the input of energy.
Facilitated diffusion (answer choice E), simple diffusion (answer choices A and D), and osmosis
(answer choice C) are all passive processes that do not require energy input.
7. C—Prokaryotes do not contain many organelles, but they do contain cell walls.
8. D—This is the description of the smooth endoplasmic reticulum. I know that this is a tricky
question, but I wanted you to review the distinction between the two types of endoplasmic
reticulum.
9. C—Microtubules play an enormous role in cell division. They make up the spindle apparatus that
works to pull apart the cells during mitosis (Chapter 5). A loss of microtubules would cripple the
cell division process. Actin fibers (answer choice D) are the building blocks of microfilaments
(answer choice A), which are involved in muscular contraction. Keratin fibers (answer choice E)
are the building blocks of intermediate filaments (answer choice B), which function as
reinforcement for the shape and position of organelles in the cell.
10. E—Lipids are the only substances listed that are able to freely diffuse across selectively
permeable membranes.
11. A
12. C
13. B
14. A
15. D
16. E
17. A
18. B
19. Ea
20. A
21. C
22. D
23. C
24. A
25. E
26. B
Chapter 8 Cell Transport
1. The solution with a lower solute concentration is hypotonic. The solution with the higher solute
concentration is hypertonic. Solutions of equal solute concentration are said to be isotonic.
2. Facilitated diffusion is still passive transport because although it increases the rate of diffusion, the
solute is still moving down a concentration gradient and energy is not used.
3. Proton pumps actively transports hydrogen ions (protons) out of the cell. It is the main electrogenic
pump of plants, bacteria, and fungi.
4. It is a mechanism in which a single ATP-powered pump transports a specific solute can indirectly drive
the active transport of several other solutes. Example: An ATP driven pump pumps H+ on one side of the
membrane, creating a concentration gradient. As H+ leaks back across the membrane through specific
transport proteins, it escorts other substances (such as sucrose) into the cell.
5. Osmosis is the movement of water through the membrane. It is passive transport. When extra water
accumulates on one side, the osmotic pressure increases.
6. Water will move into the cell. The cell will swell up and become either turgid (plants) or lysed
(animals).
7. Transport proteins are specific for the substances they transport. Thus, the numbers and kinds of
different transport proteins embedded in the membrane affect its permeability to various substances.
8. It is selectively permeable meaning that some substances can pass through but others cannot. It also
maintains homeostasis. The cell survives by preventing its interior from mixing with a watery
environment outside.
9. It is arranged in a lipid bilayer. The phospholipid structure consists of a hydrophilic head (polar) that
attracts water and a hydrophobic tail (non polar fatty acid chain) that repels water.
10. Endocytosis is when larger molecules enter as the membrane surrounds the substance. Exocytosis is
the removal of cell waste vacuoles and gland secretions through the cell membrane.
11. Pinocytosis is the intake of liquids. Phagocytosis is the intake of solids. Receptor mediated
endocytosis enables cells to acquire large quantities of specific substances.
12. Transport, enzymatic activity, signal transduction, intercellular joining, cell-cell recognition, and
attachment to the cytoskeleton and extracellular matrix.
13. Particle size/pore size, molecular weight, solubility of H2O, concentration of solvent/solute,
temperature, pressure, organic solvents/lipid solubility, and surface area/volume.
14. Membrane proteins are dispersed and individually inserted into the phospholipid bilayer, with only
their hydrophilic regions protruding far enough form the bilayer to be exposed to water. This molecular
arrangement would maximize contact of hydrophilic regions of proteins and phospholipids with water.
According to this model, the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of
phospholipids.
15. Peripheral proteins are under the phospholipid bilayer, while integral proteins are inscribed in the
bilayer. Integral proteins pass entirely through the lipid bilayer of the plasma membrane and have
domains that go from the outside of the cell to the cytoplasm inside the cell. While peripheral proteins
are only on the one side of the lipid bilayer, either the outside of the cell or the cytoplasmic side inside
the cell, but not both.
16. The sodium-potassium pump pumps ions against steep concentration gradients. The pump oscillates
between two conformation states in a pumping cycle that translocates three Na + ions out of the cell for
every two K+ ions pumped into the cell. ATP powers the changes in conformation by phosphorylating
the transport protein (transferring a phosphate group to the protein).
17. Some transport proteins function by having a hydrophilic channel that certain molecules use as a
tunnel through the membrane. Other transport proteins hold onto their passengers and physically move
them across the membrane. In both cases the transport protein is specific for the substances it moves.
18. The lipid bilayer forms non-polar interior zone. Therefore, polar molecules (glucose, amino acids,
ions, cell wastes) cannot pass through because they are repelled by the non-polar tails. *Passage of
these molecules requires certain membrane proteins.
19. They distinguish one cell from another and are involved in cell-cell recognition.
20. They are water channel proteins that facilitate massive amounts of diffusion of water.
21. Gated channels are proteins that open or close upon a stimulus, which can be electrical or chemical.
If chemical, it is a substance other than the one to be transported. For example, stimulus of a nerve cell
by neurotransmitter molecules opens gated channels allowing sodium ions into the cell.
22. Osmoregulation is the control of water balance.
23.
Plant
Animal
Hypotonic solution
Turgid (normal)
Lysed
Isotonic solution
Flaccid
Normal
Hypertonic solution
Plasmolyzed
Shriveled
24. On the cytoplasmic side, some membrane proteins are held in place by attachment to the
cytoskeleton. On the exterior side, certain membrane proteins are attached to fibers of the extracellular
matrix. The plasma membrane also has carbohydrates, which are restricted to the exterior surface. This
asymmetrical distribution of proteins, lipids, and carbohydrates is determined as the membrane is being
built by the endoplasmic reticulum. Molecules that start out on the inside face of the ER end up on the
outside face of the plasma membrane.
25. It is the combination of 2 forces that drive the diffusion of ions across a membrane: a chemical force
(the ion’s concentration gradient) and an electrical force (the effect of the membrane potential on the
ion’s movement).
CELLULAR RESPIRATION AND PHOTOSYNTHESIS
Chapter 9 Cellular Respiration
1) Compared to other elements, oxygen is very electronegative, meaning that it is very powerful in
removing electrons from other elements. Thus, it functions as an oxidizing agent in cellular
respiration, accepting/gaining electrons from the glucose molecule.
2) Cristae membranes in mitochondria play a special role in ATP synthesis. The Cristae membrane
contains electron transport chains (ETC), collections of molecules embedded in the membrane.
Most of these molecules are proteins that carry electrons from higher to lower energy levels.
The ETC uses the exergonic flow of electrons to pump protons across the cristae membrane to
the outer compartment of the mitochondria to create a proton gradient. The key here is that
the Cristae membrane does not allow protons to diffuse through the membrane. Protons can
pass through only special protein channels, large enzyme complexes, called ATP synthase
channels. As protons flow through the ATP synthase channels, like water flowing though a dam,
energy is generated to produce ATP by a process known as chemiosmosis.
3) There will be an increase in the pH difference across the inner mitochondrial membrane
because the inhibition of the ATP synthase results in no more movement of protons into the
inner mitochondrial membrane.
4) ATP consists of adenosine (the nucleotide adenine plus ribose) plus three phosphates. ATP is an
unstable molecule because the three phosphates in ATP are all negatively charged and repel one
another. When one phosphate group is removed from ATP by hydrolysis, a more stable
molecule, ADP, results. The change from a less stable molecule to a more stable molecule,
always releases energy.
5) Glycolysis (“splitting of sugar/glucose”) is the process the produces that produces raw material
for the Krebs cycle-pyruvate. 2 ATPs are needed to split glucose into 2 three-carbon molecules
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
17)
18)
of pyruvate. Glycolysis occurs in the cytoplasm and produces ATP without the use of oxygen;
ATP is produced by substrate level phosphorylation. Glysolysis nets 2 ATP amd 2 NADH.
The cell regulates ATP production through allosteric inhibition, a feedback mechanism. The
excess ATP inhibits the enzyme by altering the conformation of the enzyme, stopping glycolysis.
Both oxidative and substrate level produce ATP. Substrate level phosphorylation occurs when an
enzyme, a kinase, transfers phosphate from a substrate directly to ADP. Oxidative
phosphorylation occurs during chemiosmosis. During oxidative phosphorylation, NAD amd FAD
lose protons to the ETC which pumps them to the outer compartment of the mitochondrion,
creating a steep proton gradient which powers the phosphorylation of ADP to ATP. Simply put,
oxidative requires oxygen for redox reactions. More ATP is produced by oxidative
phosphorylation.
The ETC (electron transport chain is a collection of molecules embedded in the Cristae
membrane of the mitochondrion. The function of the ETC it to pump protons from the matrix to
the outer compartment/inner membrane; the proteins or cytochromes are the pumps. This
result in the establishment of a proton gradient which powers ATP synthase. The highly
electronegative oxygen, the final electron acceptor and component that drives the ECT and
oxidative phosphorylation, acts to pull electrons through the ETC.
NAD is a coenzyme that carries protons or electrons from glycolysis and the Krebs cycle to the
ETC. It is involved in redox reactions that power cellular respiration. NAD+ gets reduced into
NADH which delivers 2 electron and one proton to the ETC.
Its creates a “down hill” process in ETC because it attracts the electrons. It thus contributes to
the creation of ATP through oxidative phosphorylation. Its final role is accepting proton and
electrons to from water.
Alcohol fermentation is an anaerobic catabolic process or energy yielding process that occurs
without oxygen. In this process, cells convert pyruvate from glycolysis into ethyl alcohol and
carbon dioxide by oxidizing NADH back to NAD+.
Each turn of the Krebs cycle releases carbon dioxide as a waste product as well as 3 NADH, 1
ATP, 1 FADH.
Oxidation is the loss of electrons. Reduction is the gain of electrons. In cellular respiration, the
glucose gets oxidized into carbon dioxide, and the oxygen gets reduced into water.
The mitochondrion is enclosed by a double membrane. The outer membrane is smooth, but the
inner membrane or Cristae membrane is folded. ‘The inner membrane divides the
mitochondrion into two internal compartments, the outer compartment and the matrix. The
Krebs cycle takes place in the matrix. Chemiosmosis and oxidative phosphorylation take place in
the ETC which is in the Cristae.
The final electron acceptor of the ETC is oxygen (diatomic) which combines with __4__ electrons
and __4__ protons to form water.
Pyruvate must be oxidized and combine with coenzyme A to form acetyl co-A.
Cells do not catabolize carbon dioxide because most of the available energy was released by the
time carbon dioxide was formed.
Fermentation occurs without oxygen whereas cellular respiration is aerobic, occurring with
oxygen. Fermentation yields a maximum of 2 ATP from glycolysis whereas cellular respiration
19)
20)
21)
22)
23)
24)
25)
can yield a maximum of 38 ATP. The final electron acceptor in fermentation is an organic
molecule whereas the final electron acceptor in cellular respiration is oxygen.
Human skeletal muscles carry out lactic acid fermentation after strenuous exercise because the
blood cannot supply adequate oxygen.
The proton gradient-a difference in the H+ concentration on opposite sides of the inner
mitochondrial membrane- is the immediate energy source that powers ATP synthesis.
The first prokaryotes may have generated ATP from glycolysis which doesn’t require oxygen. It is
a widespread metabolic pathways among organisms that suggests that it evolved very early in
the history of life.
Temperature which affects the average kinetic energy of molecules would cause the rate to
increase. The amount of oxygen present affects the rate of respiration. If an organism is placed
in an environment with less oxygen such as one that has been polluted, then the rate of cellular
respiration will decrease.
The cell must consume glucose at a rate about 19 times the consumption rate in the aerobic
environment (2 ATP by fermentation vs. 38 ATP by cellular respiration).
Oxaloacetate.
From Glucose to NADH to ETC to proton motive force (potential energy) to ATP synthase to ATP.
Chapter 10 Photosynthesis
Review 1
1. What is photophosphorylation? What happens during this process and where does it take place?
Photophosphorylation is process of generating ATP by adding an inorganic phosphate to an ADP
molecule in the light reactions through chemiosmosis. This takes place in the thylakoid membrane
through ATP synthase.
2. Why does the light reaction have an alternate path in cyclic electron flow?
The cyclic electron flow enables electrons to photophosphorylize and produce enough ATP to power the
Calvin cycle. No NADPH or oxygen is released.
3. What mechanisms do CAM plants use to photosynthesize?
CAM stands for Crassulacean acid metabolism, a system often found in succulents (water storing plants)
like cacti and pineapples. These plants open stomata at night, close during the day (helps conserve
water). At night they incorporate CO2 into a variety of organic acids (store until later). This is a temporal
adaptation.
4. What is photorespiration? Is it useful?
Metabolic pathway that consumes oxygen and releases CO2 because Rubisco uses the more abundant
oxygen instead of CO2. This happens in hot days when the stomata closes and the oxygen concentration
exceeds those of CO2. Photorespiration is not useful at all because it decreases the photosynthetic
output since it doesn’t generate ATP or glucose but uses organic materials from the Calvin cycle.
5. What are the functions of different pigments in a plant cell?
Chlorophyll a is the main pigment present in a chloroplast. It is the only pigment that directly
participates in the light reactions. Energy absorbed by other pigments such as chlorophyll b is conveyed
to chlorophyll a. Carotenoid, xanthophyll, anthocyanin and other accessory pigments absorb different
wavelengths of light and act as photoprotection.
6. What is the Calvin cycle? What happens in it?
Calvin cycle, taking place in the stroma, is called light independent reaction. It contains 3 phases: carbon
fixation, reduction, regeneration of RuBP. With the aid of the enzyme Rubisco, RuBP (5-C compound)
captures CO2 and surrounding H+ to form an unstable 6-C compound. The 6-carbon compound
immediately splits into two 3-C PGA molecules. Electrons and energy from NADPH and ATP created in
the light dependent reactions is used to convert PGA to form G-3-P (PGAL). Two molecules of 3-C G3P
are used to form a molecule of 6-C glucose. 5 PGAL molecules are used to form RuBP to start system
again.
7. How does chemiosmosis work in plant cells?
The electron transport chain pumps protons across the thylakoid membrane into the thylakoid space
from the stroma. A chemical gradient (proton motive force) is built up where there are more protons
inside the thylakoid than in the stroma outside. The protons then diffuse back out the thylakoid through
enzymes called ATP synthase in the membrane, which turns and catalyzes the reaction where the
inorganic phosphate is attached to ADP to form ATP.
8. What are some differences between chemiosmosis in plants and animals?
Chemiosmosis occur in opposite directions. In cellular respiration, protons travel from the matrix to
intermembrane space. In photosynthesis, protons travel from the stroma to thylakoid space. Plants
undergo photophosphorylation while animals undergo oxidative phosphorylation.
9. What are photosystems in the chlorophyll?
There are 2 photosystems named Photosystem I and Photosystem II. Photosystem II splits the water
molecule at the beginning of the light reactions and gets its electrons from there. Its reaction center
chlorophyll absorbs light at wavelength of 680 nm. Photosystem I absorbs light at wavelengths of 700
nm and receives electrons from the ETC after Photosystem II.
10. What is the pathway of the electron in noncyclic electron flow?
Electrons come from the splitting of water molecule. Light energy hits the reaction center in
Photosystem II and the electron (replaced constantly from the splitting of water) gets excited to a higher
energy level. The primary electron acceptor take the electron and it travels through the electron
transport chain to Photosystem II, generating ATP through photophosphorylation and releasing energy
as it falls. The electron the fills the hole in Photosystem I and gets excited by light to a higher energy
level again. The primary electron acceptor carries the electron through a second electron transport
chain to NADP+ to form NADPH.
11. Most green plants photosynthesize efficiently under what kind of light?
Chlorophyll a is the primary light reaction center which absorbs predominantly blue and red light.
12. What environmental factors affect the rate of photosynthesis in plants?
Light intensity – increase up to a point because pigments can be damaged by intense light
Light wavelength – red or blue for chlorophyll a
Temperature of environment - ↑ up to a certain point until protein denatures. Low temperature
decrease the kinetic energy and increase energy needed for reactions
CO2 levels - increase
H2O levels – slow down because water takes up space for gas exchange.
13. What mechanisms do C4 plants use to photosynthesize?
In C4 plants, bundle sheath cells have chloroplasts. They preface Calvin cycle with 4-C acid (oxaloacetic
acid) system that uses PEP (3-C), which has a higher affinity for CO2 than rubisco. The mesophyll cells are
responsible for collecting CO2 to use for the Calvin cycle in the bundle sheath cells. This is a spatial
adaptation.
14. What role does NADP+ play in photosynthesis?
NADP+ is an electron acceptor and carrier. It receives the electrons at the end of the light reactions and
carries them to be used in the Calvin cycle.
15. How does the structure of a leaf facilitate photosynthesis?
Leaves have cuticles on the outer covering to prevent excessive transpiration. There are stomata on the
underside of a leaf that enables gas exchange. The mesophyll is the tissue layer, with the palisade
mesophyll being closely packed on the upper half of the leaf to photosynthesize. The lower spongy
mesophyll have large spaces to enable gas exchange.
16. What happens to the CO2 as it gets ready to enter the Calvin cycle? What molecules are involved?
CO2 undergoes carbon fixation through rubisco. It is then attached to RuBP to form an unstable product
that breaks down to PGA.
17. What is a spectrophotometer?
An instrument that measures the proportions of light of different wavelengths absorbed and
transmitted by a pigment solution.
18. What kind of experiments can be used to determine the effects of different wavelengths of light on
photosynthesis?
A spectrophotometer can measure the different wave length and generate an absorption spectrum or
an action spectrum. A particular experiment measured bacteria growth under different light
wavelengths with the different rate of photosynthesis from the algae in its environment.
19. Where does the oxygen come from?
The oxygen is released when water is split at Photosystem II into oxygen, 2 electrons and 2 protons.
20. What environmental challenges do CAM and C4 photosynthesis solve?
Photorespiration. They close their stomata to prevent excessive water loss in hot temperatures, causing
a buildup of oxygen and decrease of CO2.
21. How is the chloroplast similar in structure to mitochondrion?
Both have double membrane. The chloroplast is site of photosynthesis whereas the mitochondrion is
the site of cellular respiration, the reverse process of each other. In mitochondrion, the cristae increases
the surface area for ETC and chemiosmosis with many folds. The stacked grana with thylakoids also
provide increased surface area.
22. What is the importance of photosynthesis?
Photosynthesis harvests light energy from the sun to chemical energy, stored in the glucose that it
makes. The autotrophs then become food source to the primary consumers and the whole food web
above it. Photosynthesis also release oxygen as waste and uses up CO2. Animals and other organisms
depend on the availability of oxygen to undergo cellular respiration.
23. What is the structure of a chloroplast?
A chloroplast has a double membrane with intermembrane space in between. Inside the inner
membrane the space is call stroma, where the Calvin cycle takes place. Thylakoids are flat disks that are
stacked together in columns called grana. Chlorophyll and other pigments are generally found in the
thylakoid membrane. The thylakoid space help build up gradient.
24. What are action and absorption spectrums?
Action spectrum shows relative performance of different wavelengths. Absorption spectrum shows
fraction of light not transmitted.
25. What is the relationship between light reactions and the Calvin cycle?
Light reactions takes place in the thylakoid membrane, converts light energy to chemical energy, and
splits water into oxygen, electrons, and protons. It also produces ATP and NADPH needed for the Calvin
cycle. Theses materials are then used in the cycle. Without light reactions, the Calvin cycle wouldn’t
happen. The cycle takes place in the stroma, uses ATP and NADPH to convert CO2 to G3P, and returns
ADP, phosphate, and NADP+ to light reactions.
Review 2
I. Photosynthesis in Nature
 Autotrophs: Producers; sustains themselves without eating other organisms
1. Photoautotrophs: use light energy to help synthesis organic molecules
2. Chemoautotrophs: oxidize organic compounds like sulfur and ammonia
 Chloroplasts: Found in cells of mesophyll tissue (spongy); green from chlorophyll
Structure: Double membrane; stacks (grana) of thylakoids inside each chloroplast;
Stroma: dense fluid surrounding the grana.
II. The Pathways of Photosynthesis
 General equation for photosynthesis:
6CO2 + 12 H2O + Light energy  C6H12O6 + 6O2 + 6H2O
The oxygen molecule comes from the splitting of water (photolysis). 6H2O can be subtracted
from both sides to form a net equation.
 Sunlight and pigments:
Electromagnetic spectrum: entire range of radiation including visible light (380 [violet]-750 [red]
nm).
Wavelength: distance between crests of electromagnetic waves. Longer the wavelength = lower
energy
Photons: discrete particles with fixed amount of energy; the amount of energy is inversely
related to the wavelength.
Spectrophotometer: directs beams of light of certain wavelength through pigment solution and
measures the fraction of light transmitted
Absorption spectrum: fraction of light absorbed/not transmitted/not reflected
Action spectrum: Effectiveness of different wavelengths of light in driving photosynthesis
Pigments
Chlorophyll a



Color
Blue green
Description
Best with blue and red light, works directly in light
reactions, has CH3 in the molecule
Chlorophyll b
Yellow green
Transfers energy to chlorophyll a, has CHO in the
molecule
Carotenoids
Yellow and orange
Transfers energy to chlorophyll a
Xanthophyll
Yellow
Transfers energy to chlorophyll a
Anthocyanin
Red, purple, blue
Transfers energy to chlorophyll a
Chlorophyll: porphyrin ring (light absorbing head, hydrophilic, contains Mg in the middle)
Hydrocarbon tail (hydrophobic)
Factors that affect the rate of photosynthesis:
1. Light intensity: more light = higher rate; too much light = lower rate
2. Light wavelength: best = red and blue; least effective = green
3. Temperature of environment: warmer temperature = higher rate; too high = denatured
enzymes, shriveled
4. Level of CO2: more CO2 = higher rate
5. Level of H2O: too much = mesophyll tissue does not have enough room for oxygen
A. Light Reactions
Photosystems: collection of chlorophyll, proteins and other smaller organic molecules on
thylakoid membrane
Antenna complex: clusters of chlorophyll a, chlorophyll b, and carotenoids that gather light and
transmitted to a chlorophyll a molecule in the reaction center
Reaction center: special chlorophyll a loses one election (excited) to the primary electron
acceptor
Noncyclic electron flow: produces ATP and NADPH in equal amounts, noncyclic
photophosphorylation
Photosystem I: discovered first, takes wavelength of 700nm
Photosystem II: discovered second, takes wavelength of 680nm
The two photosystems occur at the same time.
1. Photolysis: water is split to give off 2 electrons and an oxygen atom which forms O2 with
another oxygen atom.
2. Electrons are excited and kept in the excited state by the primary acceptor.
3. Electron is passed down the electron transport chain (Pq  Cytochrome complex  Pc).
Chemiosmosis: the energy from the electrons powers the proton pumps to create a H+ gradient
(higher in thylakoid space, lower in stroma). When proton is diffused through ATP synthase, ATP
is created.
4. The electron transport chain from Photosystem I produces NADPH.

Cyclic electron flow: produces no NADPH and does not release oxygen, cyclic
photophosphorylation
Goal: increases ATP level because Calvin cycle uses more ATP than NADPH
Some Similarities and Differences between Mitochondrion and Chloroplast
Similarities
Mitochondrion
Chloroplast
Double membrane bound
Cellular respiration
Photosynthesis
Use chemiosmosis to generate ATP; creates
high H+ concentration in the “smaller” space
(intermembrane space and thylakoid space)
Oxidative and
substrate
phosphorylation
Cyclic and noncyclic
phosphorylation
Contains own DNA; can replicate by itself
(could be prokaryotes)
Uses NADH and FADH2
Uses NADPH
B. Calvin Cycle: “dark reactions”: light independent; 1 glucose molecule = 6 CO2 + 2 Calvin
cycles
 Location: Stroma
 Phase 1: Carbon fixation
3 CO2 molecules joins 5-carbon RuBP and enzyme Rubisco
 Phase 2: Reduction
ATP (6) and NADPH (6) from light reactions are used to form PGAL (G3P)
Output for one cycle = 1 PGAL (G3P)
 Phase 3: Regeneration of CO2 acceptor (RuBP)
5 3-carbon G3P + 3 ATP = 3 5-carbon RuBP
C. C4 and CAM Plants
Problem: When stomata close because of intense light and heat, O2 levels rise while CO2
levels decrease. Rubisco starts to take in O2 which causes photorespiration (decrease
efficiency)
1. C4 plants: steps are separated structurally: bundle sheath cell around vascular tissue have
chloroplasts
Examples: sugar cane, corn, crab grass
Solution: CO2 is “stored” in oxaloacetic acid (4-carbon acid) to use in Calvin Cycle ( in
bundle-sheath cell)
2. CAM plants: Steps are separated by time (day and night)
Examples: succulents like cacti and pineapple
Solution: CO2 is “stored” during the night in crassulacean acid system to use during the day;
water is conserved in the process
D. Overview
ECOLOGY
Chapter 50 Intro to Ecology
1) A, C, D
2) Savannah
3) Helping prevent the adult frog's body from drying out
High temperatures and wind conspire to cause terrestrial organisms to lose water, which is essential to
all living things. An adult frog has many adaptations, such as a watertight skin, that retard water loss.
4) They bring oxygenated water from the surface to the bottom and nutrient-rich water from the
bottom to the top in which organisms thrive.
5) Biotic
6) Chemicals from the Earth’s interior
7) True
8) Anatomical and Behavioral
9) Tropical Rain Forest
10) Estuary
11) the presence of algae
12) convergent evolution
13) littoral
14) coniferous forest
15) to compare the temperature and precipitation of different biomes
Chapter 51 Behavior
1. The investigation of ultimate causes of behaviors, the evolutionary basis for behaviors as mechanisms
that enhance reproductive success.
2. Proximate questions concern environmental stimuli that trigger a behavior as well as genetic
mechanisms. Ultimate questions address the evolutionary significance for a behavior and why natural
selection favors this behavior.
3. While learning is behavior modified by specific experienced, maturation is behavior that is an
improvisation due to ongoing developmental changes in neuromuscular systems.
4. Innate behavior
5. Behavioral ecology is the research field that views behavior as an evolutionary adaptation to the
natural ecological conditions of animal. Simply said, we expect animals to behave in ways that maximize
their fitness.
6. Visual, auditory, and chemical
7. A pheromone
8. Kinesis, Taxis, Landmarks, Cognitive Maps, Migration Behavior.
-Kinesis is a change in activity rate in response to a stimulus.
- Taxis are an automatic movement to or away from a stimulus.
- The use of landmark within a familiar area can be seen is how some organisms move in response to a
recognized object.
- Some animals form cognitive maps which are internal representations of the spatial relationships
among object in the individual's surrounding.
- Migration behavior includes plotting, when an animal moves from one landmark to another, and
orientation, when an animal can detect directions and travel in particular paths until reaching a
destination.
9. Sociobiology
10. Both
11. Habituation
12. Parental investment refers to the time and resources an individual must use to profuse and nurture
offspring.
13. Both are examples of associative learning. Classical conditioning involves making an association
between a stimulus and an involuntary response, while operant conditioning is about trial-and-error
learning by either receiving a reward or punishment. Examples: Classical - a dog hearing a bell ringing
that usually means mealtime causing their mouth to water. Operant- A wolf getting hit in the face when
trying to eat a porcupine.
14. - Agonistic behavior is a contest involving threats, submissive behavior, or ritual
- Reconciliation behavior happens between conflicting individuals.
- Dominance Hierarchies involve a ranking of individuals in a group.
- Territoriality is a behavior where an individual defends a particular area.
15. - Monogamous: one male mating with one female
-Polygamous: an individual of one sex mating with several of the other sex. Polygyny is a single male
with many females. Polyandry is a single female with many males.
-Promiscuous: no strong bonds between males and females
16. Reciprocal altruism.
17. A signal is a behavior that causes a change in the behavior of another animal. Communication
utilizes those signals by transmitting, receiving, and responding to them.
18. Hamilton's rule states that natural selection favors altruistic acts. He proposed a quantitative
measure for pre dicing when natural selection would favor altruistic acts called the coefficient of
relatedness. The more closely related two individuals are, the grater the value of altruism. These include
kin selection and reciprocal altruism.
19. How many offspring they produce. Inclusive fitness
20. A fixed action pattern
21. They have imprinted on humans while young and thus are attracted to their characteristics more
than those of their own species
22. Kin selection.
23. Kinesis and taxis are both types of movement. Kinesis is undirected, random movement, while taxis
is directed in relation to a given stimulus.
24. Ethology is the Study of how animals behave in their natural habitat.
25. Play
Chapter 52 Populations
1. The group of animals is called a population.
2. Uniform dispersion pattern.
3. Random dispersion pattern.
4. Clumped dispersion pattern.
5. Organisms that experience high mortality at very young age, such as larvae, but begin to experience
low mortality at a much higher age, towards max age.
6. Big-Bang Reproduction.
7. A population is a localized subset of a species.
8. Cohort
9. Carrying Capacity, the max population size.
10. A population adjusts instantaneously approaches carrying capacity smoothly.
11. Selection for life history traits that maximize reproductive success in uncrowded environments.
Density-dependent selection.
12. The predators would most likely turn against other predators and hunt them instead , decreasing the
overall predator count.
13. Explosive growth with high infant mortality.
14. The chance of survival of offspring is quite low and unpredictable.
15. The employment age of certain countries.
16. They regulate population size by keeping it from increasing over the limit.
17. Individuals may have a more difficult time surviving or reproducing if the population size is too small.
18. When the per capita birth rates and death rates are equal, or when the r value equals zero.
19. The large amount will have a higher percentage of live offspring that will eventually grow.
20. The large amount will guarantee a number of seeds will survive.
21. The large size will guarantee survival for all of the seeds even though there isn’t a high abundance of
seeds.
22. The large size of seeds does not spread out the abundance of germinating seeds.
23. The rate would equal 0.
24. The number of infants are much higher and the population is skyrocketing.
25. To have the middle ages the highest and the extremes equal to each other.
Chapter 53 Community Ecology
1. Predation
2. Parasitism
3. Mutualism- both organisms benefit, commensalism- one organism benefits while one organism is
unharmed
4. Producers
5. They are organisms that consume and break down dead plants and animals and the wastes of
other organisms.
6. Primary succession is the colonization of an area that has been untouched by any living thing.
Secondary succession is the regeneration of a living community after a major disturbance.
7. There is less competition on the new island.
8. Species richness- number of species in the area, relative abundance- the number of how many
organisms of each species in an area
9. Cryptic coloration
10. Mullerian mimicry
11. Mullerian mimicry
12. The dynamic stability hypothesis
13. Keytone species
14. The redundancy model states that if there are more species, there will be more resilience in the
community if a disturbance happens. The rivet model states that each species has a specific role
in the community, so if there was a disturbance, there would be less resiliency in the community.
15. A habitat is the area the organisms live, and a niche is the specific role that an species has in the
environment
16. The community might have many different species, but each species might have less units in the
environment.
17. Batesian mimicry is when a palatable species mimics a palatable species, while Mullerian mimicry
is when two harmful species resemble each other.
18. Ectoparasite
19. An endoparasite is a parasite that lives within their host, ectoparasites are parasites that feed on
the external surface of a host.
20. The nonequilibrium model is the model of communities that emphasizes that they are not stable
in time butc onstantly changing after being buffeted by disturbances.
21. The species area curve says that the larger the area of community, the greater the number of
species.
22. Parasitoidism
23. Coevolution is the reciprocal evolutionary adaptation of two interacting species
24. It emphasizes the feeding relationships within a community
25. The rivet model of community organization
Chapter 54 Ecosystems
1. Primary producers, primary consumers (herbivores), secondary consumers (carnivores), tertiary
consumers (carnivores that eat carnivores), detrivores.
2. Detrivores
3. Nonliving organic material (such as the remains of dead organisms, feces, fallen leaves and
wood).
4. Energy conversions cannot be completely efficient because some energy will be lost as heat in
any conversion process.
5. Primary production
6. Biomass
7. Standing crop
8. The nutrient that must be added for production to increase
9. Nitrogen/Phosphorus
10. Eutrophication
11. Secondary production
12. Production efficiency is the fraction of food energy that is not used for respiration and trophic
efficiency is the percentage of production transferred from one trophic level to the next.
13. A pyramid of numbers
14. Plants have defenses against herbivores, nutrients and not energy usually limit herbivores,
abiotic factors limit herbivores, intraspecific competition, intraspecific interactions
15. The conversion of N2 to minerals that can be used to synthesize nitrogenous organic
compounds such as amino acids; prokaryotes
16. Ammonia (NH3)
17. Humans are disrupting chemical cycles in the biosphere and have disrupted the trophic
structure and energy flow, cultural eutrophication, acid precipitation, the greenhouse effect,
global warming
18. The amount of nitrogen that can be absorbed by plants without damaging the ecosystem
integrity
19.
20.
21.
22.
Biological magnification
Release ammonia from organic compounds, thus returning it to the soil
The burning of fossil fuels and wood
An open ocean
Chapter 55 Conservation
1. The biodiversity crisis is the current rapid decrease in earth’s great variety of life.
2. The first level of biodiversity is genetic variation.
3. The third level of biodiversity is the variety of species in an ecosystem or throughout the entire
biosphere – species richness (the number of species in a biological community).
4. Both terms deal with species that are in danger. An endangered species is one that is in danger of
becoming extinct and the other is likely to become endangered in the near foreseeable future.
5. In the United States, over 25% of all prescriptions dispensed from pharmacies containing substances
derived from plants. The periwinkle plant from Madagascar inhibits cancer cells.
6. Purification of air and water, reduction of the severity of droughts and floods, generation and
preservation of fertile soils, detoxification and decomposition of wastes, pollination of crops and
natural vegetation, dispersal of seeds, nutrient cycling, control of many agricultural pests by natural
enemies, protection of coastal shores from erosion, protection from UV rays, moderation of
weather extremes, and provision of aesthetic beauty.
7. The 4 major threats to biodiversity are habitat destruction, introduced species, overexploitation,
and food chain disruptions.
8. Habitat destruction is the single greatest threat to biodiversity throughout the biosphere.
9. Mass destruction of habitats throughout the world has been brought about by agriculture, urban
development, forestry, mining, mining and environmental pollution.
10. Sometimes called exotic species, introduced species are those that humans move from the species’
native locations to new geographic regions.
11. Overexploitation is the harvesting of wild plants or animals at rates exceeding the ability of
populations of those to rebound.
12. More specifically what does overexploitation most often refers to the overhunting of elephants for
only the ivory of the tusks and the overfishing in the oceans.
13. Like falling dominoes, the extinction of on species can doom its predators.
14. The extinction vortex is the downward spiral that is unique to small populations. Ex: a small
population is prone to positive feedback loops of inbreeding and genetic drift that draw the
population down the vortex toward a smaller and smaller population size until there are no
individuals left.
15. In an ecological sense, a landscape is a regional assemblage of interacting ecosystems, such as a
forest or forest patches, adjacent open fields, wetlands, streams, and streamside (riparian) habitats.
16. Landscape ecology is important because understanding landscape dynamics Is critically important to
conservations because many species use more than one kind of ecosystem; in fact, many love on the
borders between ecosystems.
17. A movement corridor is the narrow strip of land or series of small clumps of quality habitat
connecting otherwise poo or isolated patches.
18. A biodiversity hot spot is a relatively small area with an exceptional concentration of endemic
species and a large number of endangered and threatened species.
19. Biotic boundary; legal boundary
20. A zoned reserve is an extensive region of land that includes one or more areas undisturbed by
humans surrounded by lands that have been changed by human activity and are used for economic
gain.
21. A new sub discipline of conservation biology called restoration ecology applies ecological principles
in an effort to return degraded ecosystems to conditions as similar as possible to their natural, predegraded state.
22. Bioremediation is the use of living organisms, usually prokaryotes, fungi, or plants, to detoxify
polluted ecosystems.
23. Removing; add
24. Augmenting ecosystems require determining what factors, such as chemical nutrients, have been
removed from an area and are limiting its rate of recovery.
25. The goal of the sustainable biosphere initiative is to define and acquire the basic ecological
information necessary for the intelligent and responsible development, management, and
conservation of earth’s resources.
EVOLUTION
Chapter 22 Descent with Modification
1. Origin of Species. 1st theory- species of organisms inhabiting Earth today descended from
ancestral species. Second- a mechanism for evolution/descent with modification is natural
selection.
2. A population of organisms can change over the generations if individuals with certain heritable
traits leave more offspring than other individuals. This causes evolutionary adaption or a
prevalence of inherited characteristic that improve the survival and reproduction of organisms
in certain habitats.
3. Taxonomy- branch of biology concerned with naming and classifying diverse forms of life. It is a
two- part, or binomial, system of naming organisms according to genus and species. Similar
species are grouped together in same genus. Domain- Kingdom-Phylum-Class-Order-FamilyGenus-Species. Canis lupus is an example; the genus name is capitalized. The whole name is
italicized.
4.
5. Fossils are relics or impressions of organisms from the past, preserved in rock. They are found in
sedimentary rocks formed from the sand and mud that settle to the bottom of seas, lakes, and
marshes. New layers of sediment cover older ones and compress them into superimposed layers
of rock called strata.
6. Curvier noticed that the deeper the stratum, the more dissimilar the fossils were from modern
life. He thought it was because each boundary between strata corresponded in time to a
catastrophe and that the catastrophes were confined to local geographic regions and new
species repopulated the devastated area. Hutton upheld gradualism, the theory that profound
change in Earth’s geographic features is the cumulative product of slow but continuous process.
7. Yes. Use and disuse- the idea that those parts of the body used extensively to cope with the
environment became larger and stronger while those that are not used deteriorate. Second
idea- inheritance of acquired characteristics- modifications an organism acquires during its
lifetime can be passed along to its offspring.
8. He noticed that plants and animals in temperate regions of South America were more closely
related to species living in tropical regions of the continent than to species in temperate parts of
Europe. In fact, the species of the Galapagos were like none he had ever seen in the whole
world. The finches were similar but different species. Some ate seeds, others ate insects.
9. Ob1- population size would increase exponentially if all individuals produced successfully. Ob2Populations tend to remain stable in size. Ob3- Environmental resources are limited. Inf1Production of more individuals than environment can handle leads to struggle for survival with
only a fraction of offspring surviving each generation. Ob4- Individuals of a population vary
extensively in characteristics. Ob5- Much of the variation is heritable. Inf2- Individuals whose
inherited traits best fit the environment are likely to leave more offspring than less fit
individuals. Inf3- unequal ability of individuals to survive and reproduce leads to gradual change
in a population with favorable characteristics accumulating.
10. Human suffering-disease, famine, homelessness, war was consequence of potential for human
population to increase faster than resources.
11. The breeding of domesticated plants and animals like mules from horses and donkeys and
cabbage and cauliflower are derived from wild mustard.
12. Population. Population is a group of interbreeding individuals belonging to a particular species
and sharing a common geographic area.
13. Insects that have genes that somehow can resist the chemical attack of DDTs and 3TC resistant
forms of HIV. The drug 3TC interferes with reverse transcriptase, the enzyme HIV uses to copy
its RNA genome into DNA of human host cell. It mimics cytosine nucleotide and HIV’s reverse
transcriptase picks up 3TC instead of C and HIV reproduction is blocked. The resistant HIV can
tell the difference between the real cytosine and the drug.
14. Besides the fossil record, biogeography, anatomical, embryological, and molecular homologies
support evolution .Biogeography- geographic distribution of species. Species tend to be more
closely related to other species from the same are than to species with the same way of life but
in different areas. Ex. Sugar glider and flying squirrels- convergent evolution
15. A theory is more comprehensive than a hypothesis and accounts for many facts and attempts to
explain a great variety of phenomena. It stands through thorough and continual testing by
experiment and observations. Natural selection is a theory.
16. The forelimbs of human cats, whales, bats are homologous structures (anatomical).
Embryological- vertebrate embryos have structures called pharyngeal pouches in their throat
regions. Molecular- all species share DNA and RNA.
Chapter 23 Evolution of Populations
1. Sickle cell anemia results in abnormal hemoglobin due to genetic mutation. This is a valid
explanation of heterozygote advantage. Ss individuals enjoy a certain resistance to malaria with
very little detriment from being a sickle cell carrier.
2. Cytochrome c is a protein common to many living organisms. OR Cytochrome c is found in the
electron transport chain of living organisms. This is a valid explanation involving increased
similarity in the genetic sequence of Cytochrome c. Homology is increasingly evident in more
closely related species.
3. Colored moth experiment: Conspicuously colored moth populations decreased over time.
“Camouflaged” moth populations increased over time. This is a valid explanation of natural
selection resulting in change in gene frequency.
4. Antibiotic resistant bacteria: As populations of bacteria are exposed to multiple antibiotics over
time, they become resistant. This is a valid explanation of natural selection resulting in change in
gene frequency.
5. Gradualism: Constant gradual change within and between species over time. Slow anatomical
changes throughout the fossil record
6. Punctuated Equilibrium Long periods of stagnation followed by short periods of rapid change
within and between species over time. Several strata of similar looking species followed by
significant change within a relatively short span of time.
7. Large population size; No migration; No mutation; No selection; No selective mating
8. If 1 or more of the previously mentioned 5 stipulations is NOT met, then a change in gene
frequencies is possible. This change in gene frequency can be expressed mathematically with
the equations represented at the right.
9. Percentages are represented as decimal numbers in these equations (100% = 1.00, 80% =.80,
etc.). It is therefore only logical that the total number of dominant alleles (p) and the total
number of recessive alleles (q) add up to 1.00.
10.
30% of the alleles are recessive
11.
70% of the alleles are dominant
12.
49% of the population is homozygous dominant
13.
42% of the population is heterozygous
14.
91% of the population will display brown fur
15.
A biological species is the “same kind” breeding to make fertile offspring.
16.
Habitat isolation: Separate, non-overlapping (or rarely overlapping) habitats result in
populations that simply don’t “mingle” with each other. If parasite A lives on host A and parasite
B lives on host B, it is not likely that parasite A and B will interact often; they are isolated from
each other.
Behavior isolation: Mating rituals are often very strictly adhered to by a species. Be it a song
(birds) or a particular mannerism, the outsider is unable to follow proper protocol and is thus
unlikely to get a chance at mating with an individual.
Temporal isolation: Temporal isolation is the isolation by time. If the mating season of animal A is in
the fall and animal B in the spring, it is unlikely that animal A and B will mate with each other. Some
plants are pollinated in the daytime, some at night. This too is temporal isolation.
Mechanical isolation: Anatomically incompatible species will be unable to mate. Sex organs may
incompatible. Flowers have very specific adaptations to attract their pollinators (“platforms” on which to
land, specific colors, etc.)
Gametic isolation: If the sex cells cannot come into contact, reproduction will not take place.
Aquatic gametes require water for fertilization while non aquatic gametes do not. With regard to plants,
some egg protein coats are different from one species to the next
17.
Reduced hybrid viability: Different species will have different genomes to some degree
(large or small). The haploid cells (gametes) from two different species are less likely to form a
diploid cell with a “working” genome. ; Reduced hybrid fertility: If an offspring is possible, hybrid
offspring are often sterile (horse + donkey = sterile mule); Hybrid breakdown: Over generations
the ability of the hybrid to reproduce may deteriorate (1st generation of offspring is fertile....2nd
can’t reproduce).
18.
A mountain separates previously cohabitant individuals. ; A dam or wall separates previous
cohabitants. ; Adaptive radiation is the evolution of many diversely adapted individuals from a
common ancestor. The classic example of adaptive radiation would be “island hopping”
(Darwin’s finches)
19.
The isolation of a small number of individuals from an otherwise large population could by
chance result in a very significant change in genetic makeup of that population (genetic drift).
Some alleles might be entirely absent from the small isolated population for example. These
alleles will remain absent from the population as the population grows in size. As the original
population in habitat A and “new” population in habitat “B” evolve separately over extended
periods of time, many small changes in gene frequencies add up to significant differences: a new
20.
21.
22.
23.
24.
25.
26.
species.
When a population is in H-W equilibrium, all allele frequencies or gene frequencies will
remain constant from one generation to the next.
Evolution through natural selection will disrupt H-W equilibrium. OR Evolution will result in
a change in allelic or gene frequency.
p2 or the homozygous dominant phenotype is 0.49 or 49%
2pq or the heterozygous genotype is 0.42 or 42%
q2 or the homozygous recessive genotype is 0.09 or 9%
p+q=1 p + .3 = 1 p = .7 ; The population is NOT in H-W equilibrium OR the allelic frequencies
are changing
This could be due to: natural selection, genetic mutation, selective mating, migration, small
population.
Chapter 24 Origin of Species
1. Homeotic genes.
2. The morphology is altered.
3. In the case of paedomorphis, reproductive organs mature quicker than somatic development
can occur. Body parts that were juvenile structures in an ancestral species are retained.
4. Photosensitive cells in the anterior of the organism developed further into more complex
structures that became co-opted for visual purposes. This advantageous expatiation was
favored by natural selection.
5. The gametes of different organisms were combined and allopolyploids were thus produced.
6. The two extreme phenotypes are favored, being the large and small beak sizes. This could be
due to the fact that only small seeds and large insects are available, and the intermediate
phenotype is acted against because its resource is unavailable.
7. In sexual reproduction, only half of the offspring may reproduce because males are unable to
produce children. This is less efficient; however sexual reproduction is beneficial because there
is great genetic variation. Asexual reproduction is efficient because it can occur in all offspring of
a species, and the genes are identical to its parent. This is beneficial because the organism may
continue to thrive in its environment, however if the environment changes, this organism will be
at a disadvantage due to the lack of variation.
8. Male rams fight amongst each other in order to be the stronger organism and be able to
reproduce with a female organism.
9. Female blue-footed boobies are specific in choosing their mates, so the males must shuffle their
feet in a sort of mating ritual in order to impress the female.
10. Allopatric speciation causes two populations of the same species to be separated in space by
geographical barriers. The genes of the two populations do not mix, and genetic drift and
natural selection occur differently in each population. The populations have different allele
frequencies and thus divergence eventually occurs.
11. A wolf and dog’s failure to reproduce occurs due to the prezygotic barrier of mechanical
isolation. Although the species are closely related, their reproductive organs are incompatible
and thus they may not mate.
12. A sheep and goat may be able to mate, however their hybrid zygotes are not viable because the
organisms are genetically incompatible. The development of the offspring is thus aborted.
13. The horse and donkey’s offspring, the mule, is infertile because reproductive isolation is not
overcome and genes cannot flow freely. Meiosis fails to produce normal gametes in the hybrid
because the chromosomes of the parent species differ in number and/or structure.
14. In hybrid breakdown, species are able to cross mate, and the first generation of hybrids are
viable, vigorous, and fertile organisms. However when this generation breeds with its own
hybrid species or the parent species, the offspring is weak and sterile.
15. Gametic isolation can occur because an organism has a hostile reproductive tract, fails to
recognize the gamete of the other organism, or fertilization is specific to molecules of a certain
organism.
16. Two genetically similar birds may not reproduce because they do not recognize each others
mating calls or other rituals.
17. A new species would be created because the genetic factors of the new population cause it to
be dependent on resources that the parent population is not dependent on. Individuals with the
phenotype for these dependencies are segregated from the parent population, and evolutionary
divergence occurs.
18. In Punctuated Equilibrium, sudden (thousands of years) changes in speciation are found in fossil
layers. Species undergo morphological modifications in spurts of rapidity as they bud from the
parent species. Allopatric speciation is also applied to this model as a new species extends its
range into the area of an ancestral species and is able to coexist.
19. A common ancestor/mainland species is swept off to an island. Multiple colonizations occur in
similar organisms; however they are able to coexist because they have slightly different niches.
These slight differences lead to selective pressures and thus lead to advantages in the
environment, and multiple diversely adapted species are able to thrive in the same isolated
area.
20. Ring-species are populations that vary in the level of divergence from the ancestral population
at different points around the geographic barrier because at different points, more gene flow is
able to occur than at others.
21. Anagenesis involves the accumulation of heritable changes that cause an organism to evolve to
the point that a new species is created. Cladogenesis involves the branching of new species from
a parent species.
22. Due to the fact that an organism will interact with its environment differently in changing
environmental conditions, an evolutionary trend can reverse itself or even cease completely.
23. Autopolyploidy can occur when a meiotic error causes a plant to self-fertilize. An extra set of
chromosomes (or many extra sets) in plants creates hardier species. It cannot reproduce with a
plant that has the original number of chromosomes.
24. Species are identified by relating each unique gene history to its ancestry. The most recent
common ancestry is identified and base nucleotide sequences of DNA are compared.
25. Ecological species concept.
Chapter 25 Phylogeny
1. Sedimentary strata reveal the relative ages of fossils in successive geologic periods. The absolute
ages of fossils in years can be determined by radiometric dating and other methods. The
geologic eras and periods correspond to major transitions in the composition of fossil species.
The chronology of geologic periods and eras makes up the geologic time scale.
2. Continental drift has had a significant impact on the history of life by causing major geographic
rearrangements affecting biogeography and evolution. The formation of the supercontinent
Pangaea during the late Paleozoic era and its sub sequent breakup during the early Mesozoic era
explains many biogeographic puzzles.
3. Evolutionary history has been characterized by long, relatively stable periods interrupted by
intervals of extensive species turnover--mass extinctions followed by grand episodes of adaptive
radiation.
4. Among phylogenetic hypotheses, the most parsimonious tree is the one that requires the fewest
evolutionary changes.
5. Fossils serve as a historical record over long periods of time.
6. Relative dating is the age of fossils on a geologic time scale revealed through sedimentary strata,
while absolute dating is age given in years (found most commonly through radiometric dating).
7. Linnaeus came up with the two-part Latinized name for organisms (binomial). These names are
usually italicized in test and consist of an organism's genus and species.
8. (Broadest to most specific) Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
9. Phylogenetic trees reflect hierarchical classification of taxonomic groups nestled within more
inclusive groups.
10. A clade is a monophyletic taxon (an evolutionary ancestor and all its descendants). Clades are
defined by their evolutionary novelties, or shared derived characteristics.
11. Deeper branch points represent more evolutionary divergence.
12. Monophyletic is described as an ancestral species and all of its descendant species.
13. Paraphyletic is described as an ancestor and some of its descendants.
14. Polyphyletic is described as lacking a common ancestor that would unite the species.
15. Homology is the likeness attributed to shared ancestry.
16. Species from different evolutionary branches may come to resemble one another if they have
similar ecological roles and if natural selection has shaped analogous adaptations (caused by
environmental selective forces).
17. A shared primitive character is a homology common to a taxon more inclusively (example:
backbone that predates the branching of the mammalian clade from the vertebrate tree).
18. A shared derived character is an evolutionary novelty unique to a particular clade (example:
mammary glands, hair, diaphragm).
19. An outgroup is a species or group of species that is closely related to the species being studied,
but known to be less closely related than any study group members are to each other. An
ingroup consists of organisms that are all in common.
20. When using molecular data, DNA, nucleotides, genomes, and amino acids can be used to
compare genes and proteins and reveal phylogenetic relationships.
21. Best phylogenetic hypotheses are those that incorporate extensive molecular and morphologial
data. No phylogenetic diagram is 100% correct.
22. Molecular clocks are new timing methods based on the observation that at least some regions
of genomes evolve at constant rates.
23. Base sequences of some regions of DNA change at a rate consistent enough to serve as clocks to
date episodes in past evolution.
24. Parsimony suggests that double changes in molecular evolution are less likely than inheritance
of a single change from a common ancestor.
25. A cladistic approach focuses only on the sequence of phylogenetic branching in evolution, not
on the degree of evolutionary divergence between branches.