USABO - USA Biology Olympiad Cellular Respiration and Metabolism Questions and Answers

Question 1

A scientist is studying a facultative anaerobe. Under which condition would the most ATP be produced per molecule of glucose?

Accepted Answer

In the presence of oxygen.

Answer

In the presence of oxygen and an uncoupler of oxidative phosphorylation.

Answer

In the absence of oxygen.

Answer

In the presence of a high concentration of ATP.

Question 2

Which of the following molecules acts as an allosteric inhibitor of phosphofructokinase-1 (PFK-1), a key regulatory enzyme in glycolysis?

Accepted Answer

Citrate

Answer

AMP

Answer

Fructose-2,6-bisphosphate

Answer

ADP

Question 3

During the complete oxidation of one molecule of glucose, how many molecules of CO2 are produced in the mitochondrial matrix?

Accepted Answer

6

Answer

2

Answer

4

Answer

0

Question 4

A patient is diagnosed with a rare mitochondrial disease that specifically impairs the function of Complex I (NADH dehydrogenase) in the electron transport chain. Which of the following would be a direct consequence of this condition?

Accepted Answer

Reduced pumping of protons from the mitochondrial matrix and a decreased ATP yield.

Answer

Increased ATP production from FADH2.

Answer

A complete halt of the citric acid cycle.

Answer

An accumulation of oxidized NAD+ in the mitochondrial matrix.

Question 5

In the process of chemiosmosis, the energy used to synthesize ATP is directly derived from:

Accepted Answer

The flow of protons down their electrochemical gradient through ATP synthase.

Answer

The oxidation of NADH and FADH2.

Answer

The movement of electrons between protein complexes.

Answer

The phosphorylation of glucose in the cytoplasm.

Question 6

Which metabolic pathway is common to both aerobic cellular respiration and fermentation?

Accepted Answer

Glycolysis

Answer

The citric acid cycle

Answer

Oxidative phosphorylation

Answer

Pyruvate oxidation