BIO 111 Test 3

which temperature and pH profile curves on the graphs above were most likely generated from analysis of an enzyme from a human stomach, where conditions are strongly acid? Note that the Y-axis denotes the rate of the enzyme-catalyzed reaction a. curves 1 and 4 b. curves 1 and 5 c. curves 2 and 4 d. curves 2 and 5 e. curves 3 and 4

a. curves 1 and 4

in animal cells, glycolysis occurs in the a. cytosol b. outer mitochondrial membrane c. inner mitochondrial membrane d. mitochondrial matrix e. nucleus

a. cytosol

a chemical reaction that has a positive deltaG is best described as a. endergonic b. entropic c. spontaneous d. exergonic

a. endergonic

some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquired mutations with amino acid changes that make them resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses? a. in or near the active site b. at an allosteric site c. at a cofactor binding site d. in regions of the enzyme that determine packaging into the virus capsid

a. in or near the active site

which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure above? a. A b. B c. C d. D e. E

b. B

a system at chemical equilibrium a. consumes energy at a steady rate b. can do no work c. releases energy at a steady rate d. consumes or releases energy at a steady rate, depending on whether it is exergonic or endergonic

b. can do no work

which of the following statements regarding enzymes is true? a. enzymes increase the rate of a reaction by making the reaction more exergonic b. enzymes increase the rate of a reaction by lowering the activation energy barrier c. enzymes increase the rate of a reaction by reducing the rate of reverse reactions d. enzymes change the equilibrium point of the reactions they catalyze

b. enzymes increase the rate of a reaction by lowering the activation energy barrier

which of the following best describes the forward reaction in the figure above? a. endergonic, deltaG > 0 b. exergonic, deltaG < 0 c. endergonic, deltaG < 0 d. exergonic, deltaG > 0

b. exergonic, deltaG < 0

which of the following indicates a primary path by which electrons travel downhill energetically during aerobic respiration? a. glucose --> citric acid cycle --> ATP --> NAD+ b. glucose --> NADH --> ETC --> oxygen c. glucose --> pyruvate --> acetyl CoA --> ATP --> oxygen d. glucose --> glycolysis --> ETC --> NADH --> ATP e. glucose --> glycolysis --> citric acid cycle --> NADH --> ATP

b. glucose --> NADH --> ETC --> oxygen

which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent? a. electron transport b. glycolysis c. the citric acid cycle d. oxidative phosphorylation e. establishment of proton gradient across the inner mitochondrial membrane

b. glycolysis

under a particular set of conditions in the lab, the enzyme in a chemical reaction is saturated. Which of the following alterations to the reaction will increase the rate at which substrate is converted to product? a. increasing the concentration of substrate in the reaction b. increasing the amount of enzyme in the reaction c. increasing the volume of the reaction without increasing the amount of substrate or enzyme d. decreasing the concentration of product in the reaction

b. increasing the amount of enzyme in the reaction

in the figure above, why does the reaction rate plateau at higher reactant concentrations? a. feedback inhibition by product occurs at high reactant concentrations b. most enzyme molecules are occupied by substrate at high reactant concentrations c. the reaction nears equilibrium at high reactant concentrations d. the activation energy for the reaction increases with reactant concentration d. the rate of the reverse reaction increases with reactant concentration

b. most enzyme molecules are occupied by substrate at high reactant concentrations

the complete reactions of cellular respiration in the presence of oxygen (C6H12O6 + 6 O2 --> 6CO2 + 6 H2O + energy) result in which of the following? a. oxidation of O2 and reduction of H2O b. oxidation of C6H12O6 and reduction of O2 c. reduction of CO2 and oxidation of O2 d. reduction of C6H12O6 and oxidation of CO2

b. oxidation of C6H12O6 and reduction of O2

carbon dioxide (CO2) is released during which of the following stages of cellular respiration? a. glycolysis and the oxidation of pyruvate to acetyl CoA b. oxidation of pyruvate to acetyl CoA and the citric acid cycle c. the citric acid cycle and oxidative phosphorylation d. glycolysis and citric acid cycle

b. oxidation of pyruvate to acetyl CoA and the citric acid cycle

which of the following is true for all exergonic reactions? a. the products have more total energy than the reactants b. the reaction proceeds with a net release of free energy c. they require the hydrolysis of ATP d. a net input of energy from the surroundings is required for the reaction to proceed

b. the reaction proceeds with a net release of free energy

which of the following statements concerning catabolic pathways is true? a. they combine molecules into larger, more energy-rich molecules b. they provide energy that can be used to drive cellular work c. they are endergonic d. they build up complex molecules such as protein from simpler compounds

b. they provide energy that can be used to drive cellular work

which of the following is an example of potential rather than kinetic energy? a. the muscle contractions of a person mowing grass b. water rushing over niagara falls c. a molecule of ATP d. light flashes emitted by a firefly e. protons actively moving from an area of high concentration to an area of low concentration

c. a molecule of ATP

which metabolic pathway generates a proton gradient? a. the oxidation of pyruvate to acetyl CoA b. the citric acid cycle c. electron transport chain d. glycolysis

c. electron transport chain

the complete oxidation of glucose in aerobic respiration occurs through which of the following sequence of metabolic reactions? a. glucose --> pyruvate oxidation --> citric acid cycle --> glycolysis --> electron transport chain b. glucose --> citric acid cycle --> glycolysis --> pyruvate oxidation --> electron transport chain c. glucose --> glycolysis --> pyruvate oxidation --> citric acid cycle --> electron transport chain d. glucose --> glycolysis --> citric acid cycle --> pyruvate oxidation --> electron transport chain e. glucose --> pyruvate oxidation --> glycolysis --> electron transport chain --> citric acid cycle

c. glucose --> glycolysis --> pyruvate oxidation --> citric acid cycle --> electron transport chain

where in mitochondria is the enzyme ATP synthase is localized? a. mitochondrial matrix b. electron transport chain c. inner membrane d. outer membrane

c. inner membrane

in an oxidation-reduction reaction, the reducing agent a. gains electrons and gains potential energy b. gains electrons and loses potential energy c. loses electrons and loses potential energy d. loses electrons and gains potential energy

c. loses electrons and loses potential energy

one primary function of both alcohol fermentation and lactic acid fermentation is to a. reduce NAD+ to NADH b. reduce FAD+ to FADH2 c. oxidize NADH to NAD+ d. reduce FADH2 to FAD+

c. oxidize NADH to NAD+

during glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is a. transferred to ADP, forming ATP b. released as heat c. retained in two pyruvates d. stored in the NADH produced

c. retained in two pyruvates

which of the following is true for anabolic pathways? a. they do not depend on enzymes b. they are usually spontaneous chemical reactions c. they consume energy to build polymers from monomers d. they release energy as they degrade polymers to monomers

c. they consume energy to build polymers from monomers

starting with citrate which of the following combinations of products would result from three acetyl CoA molecules entering the citric acid cycle a. 1. ATP, 2 CO2, 3 NADH, and 1 FADH2 b. 2 ATP, 2 CO2,3 NADH, 3 FADH2 c. 3 ATP, 3 CO2, 3 NADH, and 3 FADH2 d. 3 ATP, 6 CO2, 9 NADH, and 3 FADH2 e. 36 ATP, 6 CO2, 6 NADH, and 6 FADH2

d. 3 ATP, 6 CO2, 9 NADH, and 3 FADH2

which of the following is the most interpretation of the figure above? a. inorganic phosphate is created more organic phosphate b. energy from catabolism can be used directly for performing cellular work c. ADP + Pi are a set of molecules that store energy for catabolism d. ATP is a molecule that acts as an intermediary to store energy for cellular work e. Pi acts as a shuttle molecule to move energy from ATP to ADP

d. ATP is a molecule that acts as an intermediary to store energy for cellular work

yeast cells grown anaerobically can obtain energy by fermentation, which results in the production of a. ATP, NADH and pyruvate b. ATP and lactate c. ATP, CO2, and lactate d. ATP, CO2 and ethanol e. ATP, CO2, and acetyl CoA

d. ATP, CO2 and ethanol

which of the following represents the deltaG of the reaction in the figure above? a. A b. B c. C d. D e. E

d. D

which of the following statements about NAD+ is true? a. NAD+ is the source of electrons used in oxidative phosphorylation b. NAD+ has more chemical energy than NADH c. NAD+ is oxidized by the action of dehydrogenase enzymes d. NAD+ is reduced to NADH during glycolysis

d. NAD+ is reduced to NADH during glycolysis

which of the following statements is representative of the second law of thermodynamics a. conversion of energy from one form to another is always accompanied by some gain of free energy b. heat represents a form of energy that can be used by most organisms to do work c. without an input of energy, organisms would tend toward decreasing entropy d. cells require a constant input of energy to maintain their high level of organization e. every energy transformation by a cell decreases the entropy of the universe

d. cells require a constant input of energy to maintain their high level of organization

zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. the zinc most likely functions as a(n) a. competitive inhibitor of the enzyme b. noncompetitive inhibitor of the enzyme c. allosteric activator of the enzyme d. cofactor necessary for enzyme activity

d. cofactor necessary for enzyme activity

in oxidative phosphorylation what is the most direct source of energy that is used to convert ADP + Pi to ATP? a. energy released as electrons flow through the ETC b. energy released from substrate-level phosphorylation c. energy released from dehydration synthesis reactions d. energy released from movement of protons down their electrochemical gradient through ATP synthase

d. energy released from movement of protons down their electrochemical gradient through ATP synthase

which metabolic pathway is common to both cellular respiration and fermentation? a. oxidation of pyruvate to acetyl CoA b. citric acid cycle c. oxidative phosphorylation d. glycolysis e. chemiosmosis

d. glycolysis

when chemical,transport, or mechanical work is done by an organism what happens to the heat generated? a. it is used to power yet more cellular work b. it is used to store energy in the form of ATP c. it is used to synthesize ADP d. it is released to the environment

d. it is released to the environment

the oxygen consumed during cellular respiration is involved directly in which process or event? a. glycolysis b. the phosphorylation of ADP to form ATP c. the citric acid cycle d. oxidation of pyruvate to acetyl CoA e. accepting electrons at the end of the electron transport chain

e. accepting electrons at the end of the electron transport chain

the ATP produced in the citric acid cycle is generated by a. chemiosmosis b. electron transport c. photophosphorylation d. oxidative phosphorylation e. substrate-level phosphorylation

e. substrate-level phosphorylation