Chapter 7 Learning curve

The chemical bonds of carbohydrates and lipids have high potential energy because:

many of these bonds are C—C and C—H bonds, in which electrons are shared equally between atoms.

In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water.

oxidized; reduced

A simplified overall equation for respiration is as follows: C6H12O6 + 6O2 →6CO2+ 6H2O + energy In this reaction, we can say that _____ is reduced and _____ is oxidized.

oxygen; glucose

During which phase(s) of glycolysis do we observe pyruvate production, ATP synthesis, and reduction of NAD+?

payoff phase

Acetyl-CoA synthesis occurs during:

pyruvate oxidation.

Which of the following summarizes the net final products of glycolysis?

two molecules of pyruvate, two molecules of ATP, and two molecules of NADH

When a single pyruvate is converted to acetyl-CoA during pyruvate oxidation, the other products of the reaction are:

NADH and CO2.

In the cleavage phase of glycolysis:

a phosphorylated sugar molecule is broken apart and the products rearranged.

In cellular respiration, oxygen:

gains electrons and is reduced.

Which of the following are inputs, but not outputs, of glycolysis?

glucose

Which of the following is a net product of glycolysis?

2 pyruvate

What is the fully oxidized product that results from the pyruvate oxidation stage of cellular respiration?

CO2

Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of glycolysis?

0

Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of the pyruvate oxidation stage?

2

Tracing the metabolism of one glucose molecule, how many carbon atoms are available for further oxidation at the completion of the pyruvate oxidation stage?

4

Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of aerobic respiration?

6

Which of the following is required for the preparatory phase of glycolysis and then produced during the payoff phase?

ATP

Which of the following is one explanation for why glycolysis is believed to have arisen very early in the evolution of life?

It does not require oxygen.

What product of the pyruvate oxidation stage of cellular respiration will have the two electrons that are lost from pyruvate?

NADH

Which statement is true regarding pyruvate and glucose?

Pyruvate can be transported across both membranes of the mitochondrion to be further metabolized, but glucose cannot.

Which statement is true regarding pyruvate oxidation?

Pyruvate oxidation forms the same number of NADH (per glucose molecule) as glycolysis.

How did the earliest organisms on Earth most likely produce ATP?

by glycolysis

Pyruvate oxidation produces a large amount of ATP through substrate-level phosphorylation.

false

Pyruvate oxidation is an important stage in cellular respiration because:

it links glycolysis with the citric acid cycle.

During pyruvate oxidation, pyruvate is broken down into CO2 and an acetyl group. The CO2 is:

less energetic than the acetyl group

During the pyruvate oxidation stage of cellular respiration, which of the following occurs?

the formation of CO2 the formation of NADH the formation of acetyl-CoA the oxidation of pyruvate

In addition to destabilizing glucose for subsequent breakdown, what else does phosphorylation of glucose do?

traps glucose inside the cell

Although glycolysis produces four molecules of ATP by substrate-level phosphorylation, the net gain of ATP for the cell is two molecules. This is because:

two molecules are used in the initial stage.

Of the 6 carbons in a starting molecule of glucose, at the completion of pyruvate oxidation, _____ carbons are fully oxidized to _____, while _____ carbons remain in _____.

two; CO2; four; acetyl groups

Which of the following is a product (as opposed to a substrate) of at least one of the processes of cellular respiration?

water