Question 1

Which of the following structures or molecular machines is important for protein degradation in eukaryotes?

Accepted Answer

A)   cytoskeleton
B)   flagellum
C)   ribosome
D)   ATP synthase
E)   proteasomeF) None of the above
G) B) and C)

Question 2

Noncompetitive inhibition within a metabolic pathway prevents excess accumulation of the pathway's product. This occurs when the product binds the active site of an enzyme, reducing its activity, and the subsequent accumulation of product.

Accepted Answer

A) True 
 B)False

Question 3

Which of the following is TRUE for a reaction that has a ? G< 0 ?

Accepted Answer

A)   The reaction will require energy.
B)   The reaction will yield energy.
C)   The reaction is spontaneous.
D)   The reaction will require energy and is spontaneous.
E)   The reaction will yield energy and is spontaneous.F) A) and E)
G) All of the above

Question 4

Which of the following would best reflect the general steps of an enzyme-catalyzed reaction?

Accepted Answer

A)   enzyme undergoes conformational changes ? substrates bind to enzyme ? substrates are converted to products ? products are released.
B)   substrates bind to enzyme ?substrates are converted to products ? enzyme undergoes conformational changes ? products are released
C)   substrates bind to enzyme ? enzyme undergoes conformational changes ? substrates are converted to products ? products are released
D)   enzyme undergoes conformational changes ?substrates are converted to products ? substrates bind to enzyme ? products are released
E)   substrates bind to enzyme ? substrates are converted to products ? products are released ? enzyme undergoes conformational changeF) B) and D)
G) A) and C)

Question 5

hich is True of the following reaction: Pi+ADP?ATF?

Accepted Answer

A)   It has a change in free energy that is less than 0.
B)   It has a change in free energy that is greater than 0.
C)   It can be used to drive endergonic reactions.
D)   It yields energy.
E)   It has a change in free energy that is greater than 0, and hence can be used to drive endergonic reactions.F) D) and E)
G) B) and C)

Question 6

Which of the following statements about feedback inhibition in metabolic pathways is most CORRECT?

Accepted Answer

A)   The product of the pathway inhibits its own production by binding reactants in the metabolic pathway.
B)   The product of the pathway inhibits its own production by competitively inhibiting the binding of a substrate to the active site of an enzyme within the metabolic pathway.
C)   The product of the pathway inhibits its own production by noncompetitively inhibiting the binding of a substrate to the active site of an enyzme within the metabolic pathway.
D)   The product of the pathway inhibits its own production by noncompetitively binding to reactants.
E)   All of the choices are correct.F) A) and E)
G) A) and C)

Question 7

Reactions that produce glucose have less entropy than those that oxidize glucose.

Accepted Answer

A) True 
 B)False  False

Question 8

In the biochemical regulation of metabolic pathways, how would one overcome the effects of a competitive inhibitor on enzyme activity?

Accepted Answer

A)   Increase the amount of substrate for the enzyme.
B)   Increase the amount of competitive inhibitor.
C)   Increase the temperature of the reaction.
D)   Decrease the amount of enzyme.
E)   Add a noncompetitive inhibitor of the enzyme.F) A) and C)
G) C) and D) A

Question 9

Which of the following statements about catabolic reactions is FALSE?

Accepted Answer

A)   They recycle organic building blocks.
B)   They produce energy like ATP.
C)   They produce energy in the form of energy intermediates like NADH.
D)   They occur through the oxidation of substrates.
E)   They usually require an input of energy.F) C) and E)
G) A) and B)

Question 10

Which is the correct sequence of events for protein degradation in eukaryotes?

Accepted Answer

A)   ubiquitin binds target protein ? protein unfolds and enters proteasome ? protein directed to proteasome ? protein digested ? amino acids are released and recycled
B)   ubiquitin binds target protein ? protein directed to proteasome ? protein unfolds and enters proteasome ? protein digested ? amino acids are released and recycled
C)   protein directed to proteasome ? ubiquitin binds target protein ? protein unfolds and enters proteasome ? protein digested ? amino acids are released and recycled
D)   protein directed to proteasome ? protein unfolds and enters proteasome ? ubiquitin binds target protein ? protein digested ? amino acids are released and recycled
E)   protein directed to proteasome ? protein unfolds and enters proteasome ? protein digested ? ubiquitin binds target protein ? amino acids are released and recycledF) None of the above
G) B) and D)

Question 11

Which two are primary complexes for protein synthesis and degradation in eukaryotes?

Accepted Answer

A)   ribosomes and proteasomes
B)   ribosomes and lysosomes
C)   proteases and lysosomes
D)   proteases and proteasomes
E)   ribosomes and mRNAF) All of the above
G) B) and E)

Question 12

According to the first law of thermodynamics

Accepted Answer

A)   the transfer of energy increases the disorder of a system.
B)   the transfer of energy increases entropy.
C)   energy cannot be created or destroyed.
D)   once energy is created it can be destroyed.
E)   kinetic energy is based on location.F) B) and D)
G) A) and D)

Question 13

The half-life of a molecule is the time it takes for 50% of the molecule to be broken down and recycled.

Accepted Answer

A) True 
 B)False

Question 14

Which of the following statements about enzymes is FALSE?

Accepted Answer

A)   The active site of the enzyme is where the chemical reaction takes place.
B)   The substrate binds to the enzyme with low affinity.
C)   The enzyme undergoes a conformational change that brings substrates closer together in an induced fit.
D)   The optimal activity of an enzyme occurs over a narrow temperature range.
E)   The optimal activity of an enzyme occurs within a narrow pH range.F) A) and E)
G) A) and D)

Question 15

Which of the statements in INCORRECT about the following reaction? Phosphoenolpyruvate + ADP ? Pyruvate + ATP (?G = -7.5 kcal/mole)

Accepted Answer

A)   It is anabolic.
B)   It is catabolic.
C)   It can be used to drive an endergonic reaction.
D)   The synthesis of ATP occurs by substrate-level phosphorylation.
E)   It is a reaction that yields energy.F) None of the above
G) C) and D)

Question 16

Which of the following represents two general factors that determine the fate of a chemical reaction in living cells?

Accepted Answer

A)   its enzyme and rate
B)   its enzyme and direction
C)   its direction and rate
D)   its rate and product
E)   its enzyme and productsF) C) and D)
G) B) and E)

Question 17

For the generalized equation Ae- +B ?A + Be-, where e represents an electron. Which of the following statements is TRUE?

Accepted Answer

A)   Molecule A is reduced.
B)   Molecule B is oxidzied.
C)   Molecule A is oxidized.
D)   Molecule B is reduced.
E)   Both molecule A is oxidized and molecule B is reduced.F) D) and E)
G) B) and D)

Question 18

A reaction with a ?G > 0 is endergonic and requires a net input of energy.

Accepted Answer

A) True 
 B)False  True

Question 19

Which of the following statements about ubiquitin is TRUE?

Accepted Answer

A)   Ubiquitin recognizes improperly folded proteins.
B)   Ubiquitin targets proteins for degradation.
C)   Ubiquitin targets proteins for post-translational processing.
D)   Ubiquitin recognizes improperly folded proteins and targets them for degradation.
E)   Ubiquitin targets proteins for degradation and post-translational processing.F) C) and E)
G) B) and D)

Question 20

Which of the following is NOT true for ATP?

Accepted Answer

A)   It is produced from ATP synthase.
B)   It is produced by a rotary machine.
C)   Its production requires an exergonic reaction.
D)   Its hydrolysis yields energy.
E)   Its hydrolysis can drive endergonic reactions.F) A) and B)
G) A) and C)

Exam 6: An Introduction to Energy, Enzymes, and Metabolism

Which of the following structures or molecular machines is important for protein degradation in eukaryotes?

Correct AnswerverifiedShow Answer

Noncompetitive inhibition within a metabolic pathway prevents excess accumulation of the pathway's product. This occurs when the product binds the active site of an enzyme, reducing its activity, and the subsequent accumulation of product.

Correct AnswerverifiedShow Answer

Which of the following is TRUE for a reaction that has a ? G< 0 ?

Correct AnswerverifiedShow Answer

Which of the following would best reflect the general steps of an enzyme-catalyzed reaction?

Correct AnswerverifiedShow Answer

hich is True of the following reaction: Pi+ADP?ATF?

Correct AnswerverifiedShow Answer

Which of the following statements about feedback inhibition in metabolic pathways is most CORRECT?

Correct AnswerverifiedShow Answer

Reactions that produce glucose have less entropy than those that oxidize glucose.

Correct AnswerverifiedFalse

In the biochemical regulation of metabolic pathways, how would one overcome the effects of a competitive inhibitor on enzyme activity?

Correct AnswerverifiedA

Which of the following statements about catabolic reactions is FALSE?

Correct AnswerverifiedShow Answer

Which is the correct sequence of events for protein degradation in eukaryotes?

Correct AnswerverifiedShow Answer

Which two are primary complexes for protein synthesis and degradation in eukaryotes?

Correct AnswerverifiedShow Answer

According to the first law of thermodynamics

Correct AnswerverifiedShow Answer

The half-life of a molecule is the time it takes for 50% of the molecule to be broken down and recycled.

Correct AnswerverifiedShow Answer

Which of the following statements about enzymes is FALSE?

Correct AnswerverifiedShow Answer

Which of the statements in INCORRECT about the following reaction? Phosphoenolpyruvate + ADP ? Pyruvate + ATP (?G = -7.5 kcal/mole)

Correct AnswerverifiedShow Answer

Which of the following represents two general factors that determine the fate of a chemical reaction in living cells?

Correct AnswerverifiedShow Answer

For the generalized equation Ae- +B ?A + Be-, where e represents an electron. Which of the following statements is TRUE?

Correct AnswerverifiedShow Answer

A reaction with a ?G > 0 is endergonic and requires a net input of energy.

Correct AnswerverifiedTrue

Which of the following statements about ubiquitin is TRUE?

Correct AnswerverifiedShow Answer

Which of the following is NOT true for ATP?

Correct AnswerverifiedShow Answer

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