1-How many decraboxylation reactions occur during one turn of the citric acid cycle?

A) 1

B) 2

C) 3

D) 5

2-Which of the following statement is not true in the citric acid cycle?

A) Succinyl CoA → succinate is a hydrolysis reaction.

B) Fumarate → malate is a hydration reaction.

C) Malate → oxaloacetate is an oxidation reaction of a 1° alcohol

D) Isocitrate → α-ketoglutarate is an oxidation reaction of a 2° alcohol

3-ATP synthesis via oxidative phosphorylation depends on the passage of which of the following species through membrane-bound ATP synthase?

A) NADH

B) FADH2

C) H+

D) NAD+

4-In which of the following listings of citric acid cycle intermediates are the compounds listed in the order in which they are encountered in a turn of the cycle?

A) citrate,oxaloacetate,fumarate

B) isocitrate,succinylCoA,oxaloacetate

C) fumarate,malate,alpha-ketoglutarate

D) oxaloacetate, succinate, citrate

5-The final product of a series of enzyme-catalyzed reactions causes the enzyme that catalyzes the first reaction of the series to be inhibited. This is an example of

A) positiveregulatorcontrol

B) substratecontrol

C) feedbackcontrol

D) competitivecontrol

6-What type of inhibitor binds to the enzyme but does not bind at the active site?

A) a noncompetitive inhibitor

B) a competitive inhibitor

C) a reversible inhibitor

D) an irreversible inhibitor

7-Which enzyme is a zymogen?

A) Trypsinogen

B) Amylase

C) Pepsin

D) Papain

8-At a sufficiently large concentration of substrate, which enzyme-catalyzed reaction will have the lowest reaction rate?

A) Noncompetitive inhibition reaction

B) Competitive inhibition reaction

C) Uncompetitive inhibition reaction

D) Reaction rate is not affected by inhibition of enzyme activity.

9-Which of the following fat-soluble vitamins is associated with good night vision?

A) vitamin A

B) vitamin D

C) vitamin E

D) vitamin K

10-Some enzymes are produced as zymogens because

A) the reactions they catalyze are undesirable at the site of production.

B) they must have both an active site and an allosteric site, and these can’t be produced simultaneously.

C) the actual enzyme molecules are so large that they must be produced in pieces and assembled as needed.

D) the pH at the site of production is very different from the pH at the site where they are used.

11-Enzymes that are affected by the binding of an inhibitor are called

A) induced enzymes.

B) allosteric enzymes.

C) proenzymes.

D) zymogens.

12-Noncompetitive inhibition can be overcome by

A) increasing the concentration of substrate.

B) increasing the concentration of enzyme.

C) decreasing the concentration of inhibitor.

D) decreasing the concentration of products.

13-When a metal ion such as Pb(II) interferes with the functioning of an enzyme, the most probable mechanism is

A) feedback control.

B) reversible noncompetitive inhibition.

C) reversible competitive inhibition.

D) irreversible inhibition.

14-Which mineral enhances insulin function?

A) Calcium

B) Iron

C) Manganese

D) Chromium

15-Which of the following statement is true?

A) Glucoseisanaldohexose.

B) Therecanneverbemorethantwoenantiomersforamolecule.

C) Allcommondisaccharideshaveα(1→4)linkages.

D) Allpolysaccharideshaveβ(1→4)linkages.