Biology, Exam 3, All ICAs and Worksheets

2) Which parts or tissues of a plant allow transport of water and sugar respectively? A) Stoma and xylem B) Leaf and stem C) Xylem and phloem D) Phloem and xylem E) Chloroplast and mitochondrion

C) Xylem and phloem

2) The reaction as shown below, with reference to FAD, is a __________________ process and ___________ is the _(oxidizing or reduction) FAD + X-H2 -> FADH2 + X A) reduction.... X-H2 ...oxidizing B) oxidation.....FAD....reducing C) reduction... X-H2 ...reducing D) oxidation.... FAD ...oxidizing E) oxidation.... X-H2 ...oxidizing

C) reduction... X-H2 ...reducing

1) The energy released in aerobic respiration is originally derived from ________________. A) the O2 we breath. B) the ATP present in cytoplasm. C) the food we eat. D) the enzymes involved in glycolysis and Krebs cycle E) the CO2, ATP and NADH.

C) the food we eat.

When a suspension of algae is incubated in a flask in the presence of light and CO2 and then transferred to the dark, the reduction of 3-phosphoglycerate to glyceraldehyde 3-phosphate is blocked. This reaction stops when the algae are placed in the dark because A) the reaction requires CO2. B) the reaction is exergonic. C) the reaction requires ATP and NADPH D) the reaction requires O2. E) chlorophyll is not synthesized in the dark.

C) the reaction requires ATP and NADPH

1. Develop a hypothesis as to why cells have evolved to use ATP as their main energy source. How will you test this hypothesis?

Hypotheses 1: Should be testable, specific, and narrow (only a single hypothesis rather than a cluster of them. Hypothesis 2: ATP structure is compatible with the enzyme active site and enzymes could use the energy released by ATP hydrolysis. Test ATP, GTP, TTP and UTP with different enzymes that use ATP for energy coupling. Hypothesis 3: Amount of energy in ATP hydrolysis close to reaction energy levels that enzymes are capable of catalyzing. Larger minimal energy units would waste more energy. Test: Compare Kcal/mol of ATP hydrolysis to individual biochemical reaction steps and other energy carriers (sugars, amino acids, redox reactants, 02, etc.).

4) Why is it important to reduce the chromosome numbers in half for sexual reproduction of humans? A) We do not need that many chromosomes and less is better. B) Skin cells and liver cells are sensitive to increased chromosome number. C) The sperm and egg cells start with double the chromosome number. D) The sperm and egg cells fertilize and double the chromosome number. E) If we continue to half the chromosome number in meiosis then we will need a small set of chromosomes after evolution.

D) The sperm and egg cells fertilize and double the chromosome number.

2) Which of the following statements about mitosis is true? A) The chromosome number in the resulting cells is halved. B) DNA replication is completed in prophase. C) Crossing over occurs during prophase. D) Two genetically identical daughter cells are formed. E) It consists of two nuclear divisions.

D) Two genetically identical daughter cells are formed.

3) When does cyclic electron flow (at Photosystem I) important for photosynthesis? A) When there is abundant ATP. B) When there is shortage of NADPH. C) When there is shortage of ATP. D) When there is abundance of NADPH. E) When there is equal amount of ATP and NADPH.

D) When there is abundance of NADPH.

3) Centrosomes are made of _________ and they ______________. A) microfilaments....are the region where the membrane constricts during cytokinesis. B) centrioles....are constricted regions of metaphase chromosomes. C) actins....are the central region of the cell. D) centrioles....determine the plane of cell division. E) microtubules...are part of cilia.

D) centrioles....determine the plane of cell division.

3. When RuBisCO enzyme was modified to reduce the binding of oxygen to minimize photorespiration, the enzyme activity to fix CO2 to carbohydrate was also decreased. A possible explanation to this result is the A) carbon fixation reaction requires O2. B) modified enzyme prefers O2 and not CO2. C) modified enzyme prefers CO2 and not O2. D) modified enzyme lost the binding to both O2 and CO2. E) carbon fixation reaction requires light and water.

D) modified enzyme lost the binding to both O2 and CO2.

2. Give an example of a spontaneous reaction that results in a decrease in entropy.

Ice formation in winter or condensation on a cup of cold water.

1. Given a concentration of reactant X = 1 M at equilibrium, calculate the concentration of product Y at equilibrium given that Keq= 10 for reaction A and Keq= 2 for reaction B. In each case, what percentage of the reactant is converted to product?

If [S] is 1M at equilibrium, and Keq = 10, Product is 10 M and the percent of reactant converted to product is 10/10+1 X 100 = 90.9% * If [S] is 1M at equilibrium, and Keq = 2, Product is 1 M and the percent of reactant converted to product is 1/2+1 X 100 = 66.7 %.* * Note: The products come from substrate. The remainder of the substrate at equilibrium is added to the product concentration to figure out how much substrate was there to start with.

6. Define ATP

(adenosine triphosphate): an ester of adenosine and triphosphoric acid, C10H12N5O4H4P3O9, formed especially aerobically by the reaction of ADP and an orthophosphate during oxidation, or by the interaction of ADP and phosphocreatine or certain other substrates, and serving as a source of energy for physiological reactions, especially muscle contraction.

1. What are the three important things that need to happen for a eukaryotic cell division to occur?

1. DNA Replication 2. Increase in cell size and volume 3. Multiplication of cell organelles and cytoskeleton elements

2. What are the limiting factors of photosynthesis? List three major factors related to the structure and function of cell structures or components that limit the photosynthetic efficiency.

1. Light 2. Water 3. CO2 levels and 4. Temperature Cell structures: Mesophyll cells (in all plants), bundle sheath cells (in C4 plants), xylem and phloem (in all plants)

13. Define Feedback Inhibition

A cellular control mechanism in which an enzyme that catalyzes the production of a particular substance in the cell is inhibited when that substance has accumulated to a certain level, thereby balancing the amount provided with the amount needed.

2. CAM plants can keep stomata closed in daytime, reducing water loss. This is possible because they __________. A) fix CO2 into organic acids during the night by PEP carboxylase. B) use photosystems I and II during day and night. C) use the enzyme phosphofructokinase, to fix CO2 more effectively D) fix CO2 into sugars in the bundle-sheath cells. E) fix CO2 into pyruvic acid in the mesophyll cells.

A) fix CO2 into organic acids during the night by PEP carboxylase.

1) Bacteria typically have _______, whereas eukaryotes have _______. A) one chromosome that is circular; many chromosomes that are linear B) several chromosomes that are circular; many chromosomes that are linear C) one chromosome that is linear; many chromosomes that are circular D) two chromosomes that are circular; eight chromosomes that are linear E) many chromosomes that are linear; one chromosome that is circular.

A) one chromosome that is circular; many chromosomes that are linear

3. What is the difference between an absorption spectrum (shown) and an action spectrum?

Absorption spectrum is for individual pigments namely Chlorophyll a, b and Carotenoids while the action spectrum shows the level of photosynthesis, which is the result of all three pigments harvesting light energy.

5) The initiation of the S phase and the M phase of the cell cycle depends on _______ and _______ to make _______. A) actin; myosin; fibers B) Cdk; cyclin; MPF C) ligand; enzyme; complex D) insulin; receptor; G-protein E) ADP; Pi; ATP

B) Cdk; cyclin; MPF

3) How does the chromosome number of each daughter cell is reduced to half the original amount during meiosis? A) Chromosomes do not replicate during the interphase I preceding prophase I. B) Chromosomes replicate only once but before meiosis I but the cell divides twice. C) Half of the chromosomes from each gamete are lost during fertilization. D) Sister chromatids separate during anaphase I but not in anaphase II of meiosis. E) Chromosome numbers are reduced to half during crossing over in prophase I.

B) Chromosomes replicate only once but before meiosis I but the cell divides twice.

5) The energy to make ATP in oxidative phosphorylation comes from ________. A) FAD. B) NADH. C) NAD+. D) ATP. E) the O2 we inhale.

B) NADH.

3) When we exercise for a long time without rest, the muscle cells become deprived of oxygen. Which of the following is not produced in a muscle cell under such conditions? A) NADH B) ethanol C) ATP. D) pyruvate. E) lactate.

B) ethanol

4. When the phtophosphorylation is happening during light reactions, the pH of stroma will ______________ compared to the equilibrium state during night time. A) decrease as the protons are pumped back from thylakoid. B) increase as the protons are pumped into thylakoid. C) stay neutral as the protons will balance the influx and efflux D) decrease first and then increase gradually. E) stay neutral as the photophosphorylation will not affect the pH in stroma.

B) increase as the protons are pumped into thylakoid.

1) More free energy is released during the Krebs cycle than during glycolysis, but only 2 moles of ATP is produced for each mole of glucose undergoing glycolysis. Most of the remaining free energy that is produced during the Krebs cycle is used to A) synthesize GTP. B) reduce NAD+ and FAD. C) release as heat. D) oxidize pyruvate. E) make ethanol.

B) reduce NAD+ and FAD.

5) Which of the following statement is not true of glycolysis? A) ATP is used to prime the reaction. B) ATP is made in this process. C) Acetyl CoA is an output made in cytoplasm. D) NADH is produced E) Pi from cytoplasm is used to make ATP

C) Acetyl CoA is an output made in cytoplasm.

1) Which of the following in an anabolic process that is endergonic and endothermic? A) ATP + H2O -> ADP + Pi B) C6H12O6 + 6O2 -> 6CO2 + 6H2O C) CO2 + H2O -> CH2O + O2 D) FADH2 -> FAD + H2 E) CH4 + 2O2 -> CO2 + 2H2O

C) CO2 + H2O -> CH2O + O2

6) Which of the following product of Krebs cycle would inhibit a key enzyme glycolysis? A) ATP. B) Starch. C) Citrate. D) NADH. E) Acetyl CoA.

C) Citrate.

4) A chemical inhibitor that blocks the initiation of DNA replication is added to actively dividing cells. Most of the cells would be found in their ____ phase of their cell cycle. A) G0 B) S C) G1 D) G2 E) M

C) G1

6) Which of the following statements about mitosis is NOT true? A) The chromosome number in the resulting cells is identical to parents. B) DNA replication is completed in S-phase. C) Independent assortment happens in metaphase D) Two genetically identical daughter cells are formed. E) It occurs in somatic cells.

C) Independent assortment happens in metaphase

4) Which of the following is NOT directly associated with photosystem II? A) Release of oxygen. B) Harvesting of light energy by chlorophyll and other pigments C) Oxidative phosphorylation. D) Reaction center chlorophyll E) Splitting of water.

C) Oxidative phosphorylation.

5) The daughter cells become haploid after ____________________ phase of meiosis. A) Anaphase I B) Prophase I C) Telophase I D) Anaphase II E) Telophase II

C) Telophase I

2) How does the reduction of pyruvate to lactic acid during fermentation allow glycolysis to continue in the absence of oxygen? A) Water is formed during this reaction. B) This reaction is a kinase reaction. C) This reaction is coupled to the oxidation of NADH to NAD+. D) This reaction is coupled to the formation of ATP. E) This reaction is coupled to the reduction of NAD+ to NADH.

C) This reaction is coupled to the oxidation of NADH to NAD+.

Equilibrium is a stage when the ΔG is zero, i.e. there is no net change or the forward and reverse reactions are the same. If you consider an enzyme reaction, the products are formed from the substrate (same as a reactant in a chemical reaction). Keq is calculated as the number of products formed per unit substrate at equilibrium. Consider the following example as 1:1 ratio of reactant to product and calculate the Keq. B. A reaction was started with 80 mM substrate ending with 70 mM product at equilibrium.

The reaction is 1P → 1S. Givens: (i=initial and f = final) [S]i = 80 mM, [Pi] = 0 mM, and [P]f = 70 mM. Using [S]i + [P]i = [S]f + [P]f, gives us [S]f = 80mM-70mM = 10 mM. Hence Keq = [P]f/[S]f, 70mM/10mM = 7.

4. How is the light energy converted to chemical energy in light reactions of photosynthesis?

Light energy excites electrons at the reaction center chlorophyll and the high-energy electrons are passed through electron transport chain

3. Give an example of a spontaneous (exergonic) reaction that is endothermic.

Melting of ice at room temperature.

Label the following examples as exergonic or endergonic, exothermic or endothermic and if entropy increases or decreases (within the system) based on the changes in free energy, enthalpy, and entropy respectively. D. Photosynthesis

Non-pontaneous so, +ΔG, +ΔH, and -ΔS (if the system excludes sunlight used to drive it)

Label the following examples as exergonic or endergonic, exothermic or endothermic and if entropy increases or decreases (within the system) based on the changes in free energy, enthalpy, and entropy respectively. B. Active transport

Non-spontaneous so, +ΔG, +ΔH, -ΔS (if driving force like ATP hydrolysis is excluded from the system)

Label the following examples as exergonic or endergonic, exothermic or endothermic and if entropy increases or decreases (within the system) based on the changes in free energy, enthalpy, and entropy respectively. E. Amino acid biosynthesis

Non-spontaneous so, +ΔG, +ΔH, and -ΔS (system excludes ATP and other chemical potential used to drive it)

Label the following examples as exergonic or endergonic, exothermic or endothermic and if entropy increases or decreases (within the system) based on the changes in free energy, enthalpy, and entropy respectively. A. Osmosis

Spontaneous so, -ΔG, -ΔH (or ΔH=0), and +ΔS

Label the following examples as exergonic or endergonic, exothermic or endothermic and if entropy increases or decreases (within the system) based on the changes in free energy, enthalpy, and entropy respectively. C. Respiration

Spontaneous so, -ΔG, -ΔH, and +ΔS

Label the following examples as exergonic or endergonic, exothermic or endothermic and if entropy increases or decreases (within the system) based on the changes in free energy, enthalpy, and entropy respectively. F. Burning fossil fuels

Spontaneous so, -ΔG, -ΔH, and +ΔS

Given the equation for free energy change as ΔG = ΔH - TΔS, list three conditions that would result in the reaction to become spontaneous (same as exergonic or favorable).

Spontaneous/exergonic/-ΔG can result from: -ΔH and +TΔS (exothermic and increase in energy) -ΔH greater than -TΔS (exothermic outweighing a decrease in entropy) +ΔH lesser than +TΔS (endothermic outweighed by an increase in entropy)

Sprinters and marathon runners have different types of muscle tissues that use various processes to make ATP according to their needs. Speculate as to what type of ATP synthesis mechanisms operate in such individuals.

Sprinters and many weightlifters develop muscle without many mitochondria, specializing in short, intense anaerobic function (glycolysis and lactic acid fermentation). Marathoners and other endurance athletes are known to develop more vascular muscle with more mitochondria and often stored fat specializing in long-term aerobic function (Krebs cycle and OxPhos).

4. An Asian and a Caucasian graduate students walk into a bar and have a few drinks. Predict who would get drunk first and why. Use the second biochemical reaction shown above with ADH making acetaldehyde from ethanol to explain your answer.

There are variations in the enzyme, Aldehyde dehydrogenase (ALDH) that detoxify the acetaldehyde, among Asians that are less active than typical Caucasian ALDH enzyme.

2. Why is visible light important for photosynthesis and not the higher energy UV or lower energy infrared radiation?

Visible light is not only abundant and has the right energy level that does not damage the cells and has sufficient energy to excite electrons to generate proton concentration gradient and make ATP.

11. Define Active site

a region on an enzyme that binds to a protein or other substance during a reaction.

1. Define Free Energy

a thermodynamic quantity equivalent to the capacity of a system to do work.

3. Define Enthalpy

a thermodynamic quantity equivalent to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.

2. Define Entropy

a thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system.

10. Both NAD+ and FAD are a. enzymes. b. organic cofactors. c. inorganic cofactors. d. reducing agents. e. amino acids.

b. organic cofactors.

3. The change in free energy (ΔG) is best explained by the following equation. a. ∆G = ∆H + T∆S b. ∆G = ∆H - T∆S c. ∆G= ∆H + T - ∆S d. ∆G= T∆S - ∆H e. ∆G= ∆H - T + ∆S

b. ∆G = ∆H - T∆S

6. Acetoacetate synthase is a key regulatory enzyme in the beginning of the valine biosynthetic pathway. When valine accumulates above a specific concentration, it inhibits the activity of acetoacetate synthase. The mechanism of action of valine is a. competitive inhibition. b. noncompetitive inhibition. c. feedback regulation. d. chemical modification. e. irreversible inhibition.

c. feedback regulation.

2. The metabolic process most closely associated with intracellular membranes is _________.

c. oxidative phosphorylation

4. ATP is utilized in driving much cellular work because it a. uses lots of bond energy for hydrolysis. b. absorbs heat and make the body cool. c. releases free energy during hydrolysis. d. it helps in releasing O2 from photosynthesis. e. is an anabolic process important for survival.

c. releases free energy during hydrolysis.

9. Phosphoglucomutase catalyzes the reaction of glucose 6-phosphate (G6P) to fructose 6- phosphate (F6P). You are starting the reaction in a test tube with the 0.8M substrate (G6P), and you let the reaction reach equilibrium. The product (F6P) concentration at equilibrium is 0.6 M. There are no intermediates in this reaction and no products at the beginning. The Keq for this reaction is a. 1.5 b. 0.75 c. 2.0 d. 3.0 e. 4.0

d. 3.0

11. The first law of thermodynamics states that the energy a. can neither be created nor destroyed. b. the total energy of the universe is constant. c. the energy can be transferred or transformed. d. a, b, and c are correct. e. The energy transfer results in increased entropy.

d. a, b, and c are correct.

5. Enzymes are biological catalysts that can increase the rate of a biochemical reaction by a. increasing entropy and enthalpy. b. denaturing the reactants. c. decreasing the concentration of reactants. d. lowering the energy of activation. e. increasing the free energy of activation.

d. lowering the energy of activation.

12. Enzyme activity can be regulated by all the following EXCEPT a. activators. b. competitive inhibitors. c. noncompetitive inhibitors. d. phosphorylation. e. degradation.

e. degradation

5) Melting of ice at room temperature results in the following changes in free energy, enthalpy and entropy. A) +ΔG, +ΔH, +ΔS B) +ΔG, -ΔH, +ΔS C) +ΔG, -ΔH, -ΔS D) -ΔG, +ΔH, +ΔS E) -ΔG, +ΔH, -ΔS

D) -ΔG, +ΔH, +ΔS

1) ATP Hydrolysis yields 7.3 Kcal/mol free energy and it is coupled with many enzyme reactions that would not otherwise happen. Which of the following reaction can be coupled with ATP hydrolysis to become a favorable or spontaneous reaction. A reaction with a ΔG value of _______ Kcal/mol. A) -5.8 B) -7.3 C) 10.5 D) 5.3 E) 0

D) 5.3

1) The inputs of non-cyclic photophosphorylation, include light, water and ___________ A) NADP+ B) ADP, Pi C) CO2 D) A and B E) A, B and C

D) A and B

1) Which of the following poison can inhibit the generation of Δ [H+]? A) A poison that would inhibit ATP synthase. B) An enzyme that would donate electrons to O2 C) Cyanide like chemical that would block the electron transfer D) A chemical that would make the inner mitochondrial membrane leaky to ions E) A chemical that mimics glucose but is not metabolized by hexokinase

D) A chemical that would make the inner mitochondrial membrane leaky to ions

What will be the single most important chemical bond that supplies energy for the majority of the transportation we use today and what process make such bond?

• C-H bonds • Generated by photosynthesis to fix CO2 to make carbohydrate, which is then converted to other organic molecules.

7. Define Energy coupling

(1) Transfer of energy from catabolism to anabolism, or transfer of energy from exergonic process to endergonic process. (2) Free energy (from ATP hydrolysis) is coupled or functionally linked to the energy needs of another chemical reaction.

9. Define Km

(The Michaelis constant): defined as the substrate concentration at 1/2 the maximum velocity.~~ 10. Define Competitive inhibition ~form of enzyme inhibition where binding of an inhibitor prevents binding of the target molecule of the enzyme

5) An enzyme was tested with two different substrates A and B resulting in products X and Y. The Km for substrate A was 10 mM and the Km for substrate B was 100 mM. From this information, we can state that A) substrate A is less effective than substrate B to have same amount of products formed. B) substrate B is less effective than substrate A to have same amount of products formed. C) There is no difference between A and B in terms of products formed. D) X is produced less than Y with same amount of substrate used. E) Y is produced more than X with same amount of substrate used.

B) substrate B is less effective than substrate A to have same amount of products formed.

2. Draw a bacterial cell and eukaryotic cell (separately) showing the main components needed for aerobic respiration in each. Label the diagram (in between the two cells) and show the locations of where the glycolysis, Krebs cycle and oxidative phosphorylation occur in each of them.

BACTERIA cytoplasm: glycolysis, Krebs plasma membrane: ETC/OP. EUKARYOTA cytoplasm: glycolysis matrix: Acetyl-CoA formation and Krebs mitochondrial inner membrane: ETC/OP.

2. Why the respiratory poisons such as cyanide and carbon monoxide kill the cells or the organism? Elaborate as to what happens when the electron transport is blocked and why other pathways in respiration also stop.

CO blocks movement of O2 into cells where it will accept electrons at end of ETC. Cyanide blocks electrons at end of ETC from moving onto ½O2. When ETC is blocked, regeneration of NAD+ is stops which inhibits citrate synthase and stops glycolysis at GDH (uses NAD+ as a substrate).

14. Define Chemical Modification

Chemical modification describes the modification, addition or removal, through chemical reaction, of any of a variety of macromolecules, including proteins and nucleic acids.

2. Even if a couple has a million children (or more) not even two will have identical genetic make up and traits unless they are identical twins. What are the three reasons for such genetic variation and how do identical twins are born?

Crossing over (Prophase I) Independent assortment (Metaphase I and II) Random Fertilization (during mating) Identical twins are formed by a split shortly AFTER fertilization, creating two different clumps of cells with identical genomes, each developing into a separate individual.

2) When mice were fed with radioactive carbon in glucose (C6H12O6) all the 6 CO2 molecules will be released during which of the following process A) Krebs cycle and Oxidative phosphorylation B) Glycolysis and acetyl CoA formation C) Glycolysis and Krebs cycle D) Acetyl CoA formation and Krebs cycle E) Glycolysis and oxidative phosphorylation

D) Acetyl CoA formation and Krebs cycle

1) The homologous chromosomes separate during ____________________ and their sister chromatids separate during _____________ phase of meiosis. A) Anaphase I and Telophase I B) Prophase I and Anaphase II C) Metaphase I and Metaphase II D) Anaphase I and Anaphase II E) Telophase I and Telophase II

D) Anaphase I and Anaphase II

6) Non-disjunction (unequal separation) of sister chromatids possibly resulting in many genetic disorders happens during ______________of meiosis. A) Anaphase I B) Prophase I C) Telophase I D) Anaphase II E) Telophase II

D) Anaphase II

4) Which of the following would slow down or inhibit key enzymes of Krebs cycle and glycolysis? A) Excess amount of ADP and Pi B) Limited amount of ATP C) Excess amount of NAD+. D) Excess amount of citrate. E) Limited amount of FADH2.

D) Excess amount of citrate.

5) FADH2 produces less ATP each when compared to NADH because _________________ A) NADH carries 4 electrons whereas FADH2 carry only 2 electrons. B) NADH carries 2 electrons whereas FADH2 carry only 1 electron. C) Same membrane protein that accepts electrons from these molecules binds at various sites. D) FADH2 allows fewer protons transported across inner membrane and hence makes less ATP. E) NADH allows fewer protons transported across inner membrane and hence makes more ATP.

D) FADH2 allows fewer protons transported across inner membrane and hence makes less ATP.

2. Roundup herbicide is a competitive inhibitor of the enzyme EPSP-synthase in an amino acid biosynthesis pathway. Roundup can alter the a. Vmax of this enzyme. b. Km for its substrate(s). c. both a and b. d. regulatory site in enzyme. e. none of the above.

b. Km for its substrate(s).

1. Having 3 copies of the chromosome 21 causes Down syndrome. Propose a possible way as to how this may happen during meiosis.

During anaphase II of meiosis II, sister chromatids of chromosome 21 failed to separate, resulting in one gamete with no copy of chromosome 21 and one gamete with two copies of chromosome 21. The gamete containing no copy of chromosome 21 would not produce viable offspring. The gamete containing an extra copy of chromosome 21 will produce a viable offspring after fertilization with another normal gamete. This may also happen due to uneven separation in anaphase I resulting in gametes with two copies of chromosome 21. This uneven separation is referred to as non-disjunction.

4) The free energy change of a system is: ∆G = ∆H - T ∆S. Which of the following is incorrect? A) ∆G can be negative if enthalpy decreases. B) T is the absolute temperature and can change the ∆G. C) ∆G can be negative if entropy and temperature increases D) ∆S is the change in entropy and ∆H is change in enthalpy. E) A positive ∆H and negative ∆S can make ∆G negative.

E) A positive ∆H and negative ∆S can make ∆G negative.

2) Which of the following represents potential energy? A) Chemical bonds B) Water in a dam C) Charged battery D) A and B only E) A, B and C are correct

E) A, B and C are correct

3) When one consumes excessive amounts of carbohydrates, they gain weight and store excess energy as fat. Conversion of carbohydrates to fat will involve the intermediate _________. A) ATP. B) Starch. C) Citrate. D) NADH. E) Acetyl CoA.

E) Acetyl CoA.

3) What is the relation between exergonic and exothermic reactions? A) They are typically unrelated, but can be coupled with ATP hydrolysis B) Every exothermic reaction leads to a subsequent exergonic one C) Every exergonic reaction is also an exothermic one D) Both result in a reduction of entropy in the universe E) Exothermic reactions can also be exergonic processes

E) Exothermic reactions can also be exergonic processes

3. The metabolic pathway that makes FADH2 and occurs in mitochondria is ____________.

b. Krebs cycle

5) Suppose a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? A) The absorption of light energy by chlorophyll B) The splitting of water C) The flow of electrons from photosystem II to photosystem I D) The reduction of NADP+ E) The synthesis of ATP

E) The synthesis of ATP

4) The energy is stored in the form of ________ in food. A) citrate. B) fructose. C) NAD+. D) ATP. E) covalent bonds.

E) covalent bonds.

4) Migratory birds store or carry limited amounts of stored energy or food but fly over long distances. Which of the following process is most utilized in such situations to make the most amount of ATP for their flying? A) glycolysis B) ethanol fermentation C) lactate fermentation D) Krebs cycle E) oxidative phosphorylation

E) oxidative phosphorylation

2) The phases of meiosis that cause the most variation in the four daughter cells are A) prophase I and telophase II. B) prophase II and anaphase II. C) metaphase I and telophase II. D) anaphase I and prophase II. E) prophase I and metaphase I.

E) prophase I and metaphase I.

3) The reaction shown below is a/an __________________________ and it occurs during the process of _________________ . A) reduction.... Krebs cycle B) photophosphorylation.....Glycolysis C) oxidative phosphorylation.......Krebs cycle D) substrate level phosphorylation.......Krebs cycle E) substrate level phosphorylation.......glycolysis

E) substrate level phosphorylation.......glycolysis

4. Define Exergonic reaction

refers to a reaction where energy is released. Because the reactants lose energy (G decreases), Gibbs free energy (ΔG) is negative under constant temperature and pressure. These reactions usually do not require energy to proceed, and therefore occur spontaneously.

3. Methanol is toxic and any accidental drinking of methanol can make one blind or cause death. A person who drank some methanol is asked to drink ethanol as an antidote. Shown below in the enzyme reaction of Alcohol Dehydrogenase (ADH) on these two substrates. Briefly explain how this treatment works. Methanol + ADH -> Formaldehyde Ethanol + ADH -> Acetaldehyde

Formaldehyde is toxic, especially to the liver. Acetaldehyde is not. Ethanol competes for the same active site of ADH that methanol binds to. ADH is so busy converting ethanol to acetaldehyde that the kidneys excrete methanol from the body before a lethal amount of formaldehyde can build up.

Equilibrium is a stage when the ΔG is zero, i.e. there is no net change or the forward and reverse reactions are the same. If you consider an enzyme reaction, the products are formed from the substrate (same as a reactant in a chemical reaction). Keq is calculated as the number of products formed per unit substrate at equilibrium. Consider the following example as 1:1 ratio of reactant to product and calculate the Keq. A. At equilibrium, the reactant remaining was 200 µg/ml and the product was 800 µg/ml

If the reaction is 1P → 1S, Keq = [P]/[S], [S] = 200 µg/ml, and [P] = 800 µg/ml, then Keq = 800/200 = 4.

3. While animals will be killed by cyanide, plants are not affected by cyanide. Research and find out the reasons.

In addition to the conventional complex IV (cytochrome C oxidase) which pumps protons against the H+ gradient, many plant mitochondria contain an alternative complex IV which does not pump protons, but does use O2 to oxidize cytochrome C and is cyanide-insensitive.

1. Compare and contrast substrate level phosphorylation with oxidative phosphorylation providing two similarities and three differences.

Similarities: • Both make ATP by combining ADP + Pi → ATP, • Couple energy from an exergonic process into the endergonic phosphorylation process. Differences: • SLP produces much less ATP compared to OP. • SLP driven by chemical energy source, • OP driven by proton-motive force (chemical and electrical potential). • OP happens exclusively across mitochondrial membrane, SLP happens in the cytoplasm and matrix. • SLP much faster than OP. • OP requires O2, SLP happens in presence or absence of O2.

Compare and contrast photophosphorylation and oxidative phosphorylation with two similarities and three differences.

Similarities: Both make ATP and use electron transport chain, proton concentration gradient and Chemiosmosis to make ATP Differences: Oxidative phosphorylation occurs in mitochondrial inner membrane, utilizes NADH/FADH2, O2 and releases NAD+/FAD and H2O. Photophosphorylation occurs on thylakoid membrane and uses light energy to make ATP.

1. Propose a hypothesis for chronic fatigue syndrome and how you can overcome this.

Slow catalysis or weak substrate binding of any enzyme in OxPhos. Treatment by mimicking signals that would increase expression of this enzyme

1. CH4 + 2 O2 CO2 + 2 H2O + 160 kCal/mol energy is an example of a/an a. exothermic reaction. b. endothermic reaction. c. endergonic reaction. d. cooling reaction. e. anabolic reaction.

a. exothermic reaction.

12. Define Allosteric enzyme

an enzyme that contains a region to which small, regulatory molecules ("effectors") may bind in addition to and separate from the substrate binding site and thereby affect the catalytic activity.

8. Define Vmax

the maximum velocity or rate at which the enzyme catalyzed a reaction. It happens when all enzyme active sites are saturated with substrate.

2. List three real life examples of how enzyme activity is affected by pH, salt concentration and temperature.

pH: Activation of hydrolytic enzymes by the low pH of stomach acid, high pH of bile, or low pH of lysosome. Entire activity of endomembrane system is governed by pH. Salt concentration: Dependence of human enzymes on correct intracellular salt concentration (too high → dehydration and death). Likewise saltwater and freshwater fish suffer shock and death if placed in salt concentrations they're not adapted to. Temperature: Freezing and refrigerating foods slows enzyme reaction rates in organisms that cause spoilage and in the food itself. Blanching (immersion in hot water) before freezing completely deactivates enzymes and further increases shelf-life. A moderate fever increases activity of immune system and causes difficulty for invading organisms. Too high of a fever will inactivate enzymes necessary for brain function causing death. Others examples include heat shock, hypothermia, etc.

5. Define Endothermic reaction

refers to a chemical reaction in which energy is being used in the overall reaction, making the reaction non-spontaneous and thermodynamically unfavorable. Due to this consumption of energy, standard change in Gibbs free energy (ΔG) is a positive value under constant pressure and temperature: ΔG° > 0.