Question 1

A holoenzyme can consist of:

Accepted Answer

A)  an apoenzyme plus a cofactor
B)  an apoenzyme plus a coenzyme
C)  a protein and non-protein component
D)  all of the aboveE) All of the above
F) None of the above

Question 2

As electrons are passed from carrier to carrier,their energy changes.At which point in the chain would you expect the energy of the electrons to be the highest?

Accepted Answer

A)  A
B)  B
C)  C
D)  D
E)  EF) C) and D)
G) B) and C)

Question 3

A surfactant:

Accepted Answer

A)  lowers the surface tension at the bacterium's posterior end allowing Myxococcus to glide
B)  is metabolized to produce phosphoenolpyruvate
C)  forms channels through the outer membrane
D)  emits light as it returns to its unexcited stateE) A) and B)
F) A) and C)

Question 4

How is ATP formed by chemiosmosis?

Accepted Answer

A)  Proton gradient across a membrane provides motive force
B)  Nitrates are used as their final electron acceptor
C)  The last step involves H₂O to be split into O₂
D)  All of the metabolites enter the Krebs cycleE) A) and D)
F) A) and C)

Question 5

Enzymes work by:

Accepted Answer

A)  lowering the energy of the reactants.
B)  raising the energy of the products.
C)  decreasing the activation energy of the reaction.
D)  increasing the activation energy of the reaction.E) B) and C)
F) A) and B)

Question 6

The first step in protein metabolism is the breakdown of proteins into:

Accepted Answer

A)  nucleotides
B)  fatty acids
C)  amino acids
D)  coenzymesE) A) and C)
F) B) and D)

Question 7

Which statement about fermentation is true?

Accepted Answer

A)  All fermentation of pyruvic acid always results in the same end product.
B)  All fermentation starts with glucose going through glycolysis.
C)  The same fermentation reaction produces both wine and cheese.
D)  None of the aboveE) A) and D)
F) All of the above

Question 8

Chemiosmosis:

Accepted Answer

A)  forms ATP
B)  occurs in the cell membrane of prokaryotes
C)  uses a proton gradient to activate ATP synthase
D)  all the aboveE) A) and D)
F) None of the above

Question 9

The initial substrate molecule for the Krebs cycle is:

Accepted Answer

A)  pyruvic acid
B)  acetyl-CoA
C)  acetic acid
D)  butanediolE) All of the above
F) None of the above

Question 10

In photosynthesis,light energy is used to:

Accepted Answer

A)  break down proteins
B)  phosphorylate ADP to form ATP
C)  synthesize carbohydrates
D)  two of these choicesE) C) and D)
F) B) and D)

Question 11

Which of the following statements about enzyme inhibition is true?

Accepted Answer

A)  Most noncompetitive inhibitors bind to several different sites on an enzyme.
B)  Enzymes become less efficient as temperatures drop because they begin to denature.
C)  Noncompetitive inhibitors bind to a site other than the active site.
D)  Most human enzymes have an optimum temperature below normal body temperature.E) C) and D)
F) B) and C)

Question 12

During the metabolism of fats,the product of beta-oxidation enters:

Accepted Answer

A)  glycolysis
B)  Krebs cycle
C)  oxidative phosphorylation
D)  electron transport chainE) A) and D)
F) None of the above

Question 13

Oxidation is defined as the ________ while reduction is the ________ .

Accepted Answer

A)  gain of electrons, loss of protons
B)  loss of electrons, gain of protons
C)  loss of electrons, gain of electrons
D)  loss of protons, gain of protonsE) B) and C)
F) B) and D)

Question 14

Competitive inhibition of enzymes occurs when the inhibitor:

Accepted Answer

A)  binds to the active site of the enzyme.
B)  binds to the allosteric site of the enzyme.
C)  changes the shape of the enzyme.
D)  is acted upon by the enzyme.E) A) and B)
F) A) and C)

Question 15

Sulfa drugs bind to the active site of the enzyme which normally converts para-amino benzoic acid (PABA) to folic acid,preventing the production of folic acid and,eventually purine synthesis. In this case,the sulfa drug is acting as a/an:

Accepted Answer

A)  allosteric inhibitor
B)  competitive inhibitor
C)  noncompetitive inhibitor
D)  uncompetitive inhibitorE) All of the above
F) A) and B)

Question 16

Which statement is true about enzymes?

Accepted Answer

A)  Enzyme-catalyzed reactions would not go forward without their specific enzymes.
B)  Most enzymes catalyze several different reactions.
C)  Coenzymes are organic molecules while cofactors are inorganic molecules.
D)  A holoenzyme is an apoenzyme that is missing its cofactor.E) A) and B)
F) C) and D)

Question 17

Which of the following is not a carrier molecule that carries hydrogen atoms or electrons in oxidative reactions?

Accepted Answer

A)  Cytochrome
B)  FAD
C)  Niacin
D)  NAD⁺E) A) and B)
F) B) and C)

Question 18

All of the following are electron acceptors for anaerobic respiration,except:

Accepted Answer

A)  carbon dioxide
B)  oxygen
C)  nitrate ions
D)  sulfate ionsE) C) and D)
F) All of the above

Question 19

In algae,the dark reactions of photosynthesis occur in the:

Accepted Answer

A)  cell membrane
B)  matrix of the mitochondria
C)  stroma of the chloroplast
D)  nucleusE) B) and D)
F) A) and B)

Question 20

At which temperature do enzymes begin to denature?

Accepted Answer

A)  20 degrees Celsius
B)  30 degrees Celsius
C)  40 degrees Celsius
D)  50 degrees CelsiusE) A) and B)
F) B) and D)

Exam 5: Essential Concepts of Metabolism

Which statement is true about enzymes?

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A holoenzyme can consist of:

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All of the following are electron acceptors for anaerobic respiration,except:

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As electrons are passed from carrier to carrier,their energy changes.At which point in the chain would you expect the energy of the electrons to be the highest?

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In photosynthesis,light energy is used to:

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The initial substrate molecule for the Krebs cycle is:

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Enzymes work by:

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Which of the following statements about enzyme inhibition is true?

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Competitive inhibition of enzymes occurs when the inhibitor:

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At which temperature do enzymes begin to denature?

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A surfactant:

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The first step in protein metabolism is the breakdown of proteins into:

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In algae,the dark reactions of photosynthesis occur in the:

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Chemiosmosis:

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Oxidation is defined as the ________ while reduction is the ________ .

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During the metabolism of fats,the product of beta-oxidation enters:

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Which of the following is not a carrier molecule that carries hydrogen atoms or electrons in oxidative reactions?

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Which statement about fermentation is true?

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How is ATP formed by chemiosmosis?

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Sulfa drugs bind to the active site of the enzyme which normally converts para-amino benzoic acid (PABA) to folic acid,preventing the production of folic acid and,eventually purine synthesis. In this case,the sulfa drug is acting as a/an:

Correct AnswerverifiedShow Answer

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Oxidation is defined as the while reduction is the .

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