LS7A Launchpad Cellular Respiration

The phosphorylation of glucose during glycolysis serves to: (Select all that apply.)

destabilize the molecule, making it easier to cleave, trap imported glucose inside the cell

The proteins of the electron transport chain are:

embedded in the inner mitochondrial membrane

The first phase of glycolysis requires the input of two ATP molecules. It is therefore:

endergonic

fermentation takes place

in the cytoplasm

PFK-1 is _____ by ATP and _____ by ADP.

inhibited; activated

Protons in a mitochondrion flow through an ATP synthase from the

intermembrane space to the matrix.

During the citric acid cycle, the production of CO2 is the result of the _____ of intermediate compounds of the citric acid cycle coupled to the production of _____.

oxidation; NADH

In eukaryotes, pyruvate oxidation takes place in the:

mitochondrial matrix

The citric acid cycle takes place in the:

mitochondrial matrix.

A molecule that is _____ loses electrons, and a molecule that is _____ gains electrons.

oxidized; reduced

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

oxidized; reduced

What is the FINAL electron acceptor in the electron transport chain?

oxygen

During fermentation, pyruvate is

reduced

The _____ forms of the electron carriers NAD+/NADH and FADH/FADH2 have high potential energy.

reduced

Consulting Figure 7.3 if necessary, during which stage(s) of cellular respiration is carbon dioxide released?

stages 2 and 3

In glycolysis, ATP is synthesized by:

substrate-level phosphorylation.

In eukaryotic cells, glycolysis occurs in:

the cytoplasm.

A single molecule of glucose requires _____ "turn(s)" through the citric acid cycle for its chemical energy to be completely harvested.

2

Which of the following molecules would you expect to act as allosteric activator of an enzyme in glycolysis?

ADP

Phosphofructokinase (PFK) is an allosteric enzyme that catalyzes a key step in glycolysis. Which of the following is TRUE about this enzyme? (Select all that apply.)

ATP acts as an inhibitor of PFK activity, ADP and AMP are allosteric activators of PFK activity

During the citric acid cycle:

ATP is synthesized by substrate-level phosphorylation

Which of the following is the most important product of the fermentation pathway in animal cells?

NAD+

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

NADH and CO2

Which one of the following represents the REDUCED forms of the two major electron carriers?

NADH and FADH2

We consume a variety of carbohydrates that are digested into a variety of different sugars. How do these different sugars enter glycolysis?

Sugars are converted to various forms and enter glycolysis at various stages

Certain complexes of the mitochondrial electron transport chain pump protons. Which of the following BEST describes the movement of protons in this situation?

across the inner mitochondrial membrane, from the matrix to the intermembrane space

Excess glucose is stored in large branched molecules of:

glycogen in animals

Pyruvate oxidation is an important stage in cellular respiration because it:

links glycolysis with the citric acid cycle.

At the end of glycolysis, the carbon molecules originally found in the starting glucose molecule are in the form of:

two pyruvate molecules

In the absence of carbohydrates, which of the following can maintain production of NADH and FADH2 by the citric acid cycle?

β-oxidation of fatty acids