AP Bio Chapter 7

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the electron transport chain?

0%

What fraction of the carbon dioxide exhaled by animals is generated by the oxidation of pyruvate to acetyl CoA, if glucose is the sole energy source?

1/3

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?

100%

If a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely oxidized to carbon dioxide and water, approximately how many ATP molecules can the cell synthesize for each molecule of pyruvate completely oxidized to carbon dioxide and water?

14

How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?

2

For each molecule of glucose consumed in glycolysis, there is a net consumption of which of the following?

2 NAD+ and 2 ADP

Glycolysis results in a net production of which of the following from each molecule of glucose?

2 NADH, 2 pyruvate, and 2 ATP

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

2 NADH, 2 pyruvate, and 2 ATP.

Approximately how many molecules of ATP are produced by substrate-level phosphorylation during the complete oxidation of a molecule of glucose (C6H12O6) in aerobic cellular respiration?

4

The complete oxidation of glucose (C6H12O6) to carbon dioxide and water in aerobic respiration consumes how many molecules of oxygen (O2)?

6

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

60-64

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

Early steps consume energy from ATP, and later steps store an increased amount of energy in ATP and NADH.

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?

FADH2

In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve?

It increases the surface area for oxidative phosphorylation.

The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mol, and the free energy for the reduction of NAD+ to NADH is +53 kcal/mol. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?

Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis.

Which of the following statements about NAD+ is true?

NAD+ is reduced to NADH during glycolysis.

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the highest energy level?

NADH

In addition to ATP, what are the end products of glycolysis?

NADH and pyruvate

Why are carbohydrates and fats considered high-energy foods?

They have a lot of carbon atoms bound together by single covalent bonds.

In the complete reactions of aerobic respiration, the energy for the majority of ATP synthesis is provided by

a proton gradient across a membrane.

Which kind of metabolic poison would most directly interfere with glycolysis?

an agent that closely mimics the structure of glucose but is not metabolized

The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of

an endergonic reaction coupled to an exergonic reaction.

Metabolic pathways that release stored energy by breaking down complex molecules are known as

catabolic pathways

Inside an active mitochondrion, most electrons follow which pathway?

citric acid cycle → NADH → electron transport chain → oxygen

In animal cells, glycolysis occurs in the

cytosol

In chemiosmosis, what is the most direct source of energy that is used to convert ADP + ℗i to ATP?

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

In an oxidation-reduction reaction, the reducing agent

gains electrons and gains potential energy.

The complete oxidation of glucose in aerobic respiration occurs through which of the following sequence of metabolic reactions?

glucose → glycolysis → pyruvate oxidation → citric acid cycle → electron transport chain

A molecule that is phosphorylated

has increased chemical potential energy that may be used to do cellular work.

Where in mitochondria is the enzyme ATP synthase localized?

inner membrane

Where are the proteins of the electron transport chain located?

inner mitochondrial membrane

As a result of an oxidation-reduction reaction the oxidizing agent

loses electrons and loses potential energy.

Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?

mitochondrial intermembrane space

What is the source of the oxygen used to form water in the complete reactions of cellular respiration?

molecular oxygen (O2)

The complete reactions of cellular respiration in the presence of oxygen (C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy) result in which of the following?

oxidation of C6H12O6 and reduction of O2

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

oxidation of pyruvate to acetyl CoA and the citric acid cycle

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?

oxidative phosphorylation (chemiosmosis)

The ATP produced in the citric acid cycle is generated by

oxidative phosphorylation.

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the glucose molecule becomes

oxidized

The energy used to pump hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space is derived from

redox reactions in the electron transport chain.

During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is

retained in the two pyruvates

The primary role of oxygen in cellular respiration is to

serve as an acceptor for electrons and hydrogen, forming water.

The ATP produced in glycolysis is generated by

substrate-level phosphorylation

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

the creation of a proton-motive force.

What is the proton-motive force?

the force provided by a transmembrane hydrogen ion gradient

As a result of the transfer of an electron from a less electronegative atom to a more electronegative atom,

the more electronegative atom is reduced, and energy is released.

The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation in eukaryotic cells is

the proton-motive force across the inner mitochondrial membrane.

In glycolysis, for each molecule of glucose oxidized to pyruvate,

two molecules of ATP are used and four molecules of ATP are produced.