Chapter 9- Set 1

In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs?

Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH.

Which of the following accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle?

Release of CO2 and synthesis of NADH

Where do the reactions of glycolysis occur in a eukaryotic cell?

The cytosol

Why is the citric acid cycle called a cycle?

The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the cycle.

Where do the reactions of the citric acid cycle occur in eukaryotic cells?

The matrix of the mitochondrion

Oxygen gas (O2) is one of the strongest oxidizing agents known. The explanation for this is that __________.

The oxygen atom is very electronegative

In glycolysis, there is no production of carbon dioxide as a product of the pathway. Which of the following is the best explanation for this?

The products of glycolysis contain the same total number of carbon atoms as in the starting material.

A small amount of ATP is made in glycolysis by which of the following processes?

Transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation

In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and after a few minutes radioactive oxygen atoms showed up in __________.

carbon dioxide

A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to kill bacteria in people with infections. However, he cannot do this because __________.

human cells must also perform glycolysis; the drug might also poison them

After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of __________.

NADH

The function of cellular respiration is to __________.

Extract usable energy from glucose

Which of the following represents the major (but not the only) energy accomplishment of the citric acid cycle?

Formation of NADH and FADH2

How many molecules of ATP are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen?

Four

Which process is the one in which glucose is oxidized to generate two molecules of pyruvate, and in which ATP and NADH are produced?

Glycolysis

Each ATP molecule contains about 1% of the amount of chemical energy available from the complete oxidation of a single glucose molecule. Cellular respiration produces about 32 ATP from one glucose molecule. What happens to the rest of the energy in glucose?

It is converted to heat.

A molecule becomes more oxidized when it __________.

Loses an electron

Which of the following statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a one-hour class period in a classroom of 300 students if the heating and air conditioning is turned off and all doors are kept closed?

Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration.

Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes?

The citric acid cycle

Of the following molecules in the glycolytic pathway (the process of glycolysis), the one with the most chemical energy is __________.

fructose-1,6-bisphosphate

In the overall process of glycolysis and cellular respiration, __________ is oxidized and __________ is reduced.

glucose; oxygen

Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration?

oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation

Most of the ATP produced in cellular respiration comes from which of the following processes?

oxidative phosphorylation

During the reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction?

oxygen

In the citric acid cycle, for each pyruvate that enters the cycle, one ATP, three NADH, and one FADH2 are produced. For each glucose molecule that enters glycolysis, how many ATP, NADH, and FADH2 are produced in the citric acid cycle?

two ATP, six NADH, two FADH2