Homework #4 Quiz

the activation energy barrier for this reaction cannot be overcome

A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because..

~64

Approximately how many molecules of ATP are produced from the complete oxidation of TWO molecules of glucose (C6H12O6) in aerobic cellular respiration?

oxidation of pyruvate to acetyl CoA and the citric acid cycle

Carbon dioxide (CO2) is released during which stage of cellular respiration?

the mitochondrial matrix

During cellular respiration, acetyl CoA accumulates in what location?

12

For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH + FADH2 molecules produced?

by changing the shape of the enzyme's active site

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction? Select one: a. by acting as a coenzyme for the reaction b. by binding at the active site of the enzyme c. by changing the shape of the enzyme's active site d. by changing the free energy change of the reaction e. by decreasing the activation energy of the reaction

6

How many oxygen molecules (O2) are required each time a molecule of glucose (C6H12O6) is completely oxidized to carbon dioxide and water via aerobic respiration?

energy released from movement of protons through ATP synthase, down the electrochemical gradient

In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP?

1

In the citric acid cycle, if you start with one molecule of isocitrate and ending with fumarate, how many ATP molecules can be made through substrate-level phosphorylation?

competitive inhibition

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? Select one: a. insufficient cofactors b. allosteric inhibition c. competitive inhibition d. saturation of the enzyme activity e. denaturization of the enzyme

2 NADH, 2 pyruvate, and 2 ATP

Starting with one molecule of glucose, the energy-containing products of glycolysis are

substrate-level phosphorylation

The ATP made during glycolysis is generated by Select one:

is involved in the catalytic reaction of the enzyme

The active site of an enzyme is the region that

feedback inhibition

The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as

act as an acceptor for electrons and hydrogen, forming water

The primary role of oxygen in cellular respiration is to

glycolysis

What process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?

reduced

When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes

creation of a proton-motive force

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the

mitochondrial inner membrane

Where are the proteins of the electron transport chain located?

acetyl CoA

Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate? Select one: a. citrate b. lactate c. glyceraldehyde-3-phosphate d. acetyl CoA e. oxaloacetate

NADH, FADH2, and O2

Which of the following is the combination of substances that is initially added to the electron transport chain? Select one: a. oxygen and protons b. NAD+, FAD, and electrons c. NADH, FADH2, and protons d. oxygen, carbon dioxide, and water e. NADH, FADH2, and O2

oxidative phosphorylation (chemiosmosis)

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water? Select one: a. oxidation of pyruvate to acetyl CoA b. citric acid cycle c. fermentation d. oxidative phosphorylation (chemiosmosis) e. glycolysis

C6H12O6 is oxidized and O2 is reduced

Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy Select one: a. C6H12O6 is reduced and CO2 is oxidized. b. O2 is oxidized and H2O is reduced. c. CO2 is reduced and O2 is oxidized. d. O2 is reduced and CO2 is oxidized. e. C6H12O6 is oxidized and O2 is reduced.

The reaction is faster than the same reaction in the absence of the enzyme

Which of the following statements is true about enzyme-catalyzed reactions? Select one: a. Enzyme-catalyzed reactions require energy to activate the enzyme. b. The reaction always goes in the direction toward chemical equilibrium. c. The free energy change of the reaction is opposite from the reaction that occurs in the absence of the enzyme. d. Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions. e. The reaction is faster than the same reaction in the absence of the enzyme.

It uses stored ATP and then forms a net increase in ATP

Why is glycolysis described as having an investment phase and a payoff phase?

cofactor necessary for enzyme activity

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): Select one: a. allosteric activator of the enzyme. b. cofactor necessary for enzyme activity. c. noncompetitive inhibitor of the enzyme. d. coenzyme derived from a vitamin. e. competitive inhibitor of the enzyme.