AP-Micro Microbiology: Microbial Metabolism 2

Question 1

Which enzyme complex is responsible for pumping protons across the inner mitochondrial or bacterial membrane during electron transport?

Accepted Answer

NADH dehydrogenase (Complex I)

Answer

NADH dehydrogenase (Complex I) oxidizes NADH and pumps protons across the membrane, contributing to the proton motive force.

Question 2

What is the net ATP yield from substrate-level phosphorylation during glycolysis alone (per glucose)?

Accepted Answer

2 ATP

Answer

Glycolysis produces 4 ATP but consumes 2 ATP for a net yield of 2 ATP via substrate-level phosphorylation.

Question 3

A bacterium living in a deep-sea hydrothermal vent uses H2S as an electron donor to fix CO2. This organism is best classified as a:

Accepted Answer

Chemoautotroph (lithotroph)

Answer

Chemoautotrophs (lithotrophs) obtain energy from inorganic compounds like H2S and use CO2 as a carbon source.

Question 4

During the citric acid cycle, how many NADH molecules are produced per acetyl-CoA entering?

Accepted Answer

3

Answer

Three NADH molecules are generated per acetyl-CoA in the TCA cycle at isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, and malate dehydrogenase.

Question 5

Which metabolic process directly produces FADH2 in the TCA cycle?

Accepted Answer

Succinate → fumarate

Answer

Succinate dehydrogenase oxidizes succinate to fumarate using FAD as the electron acceptor, generating FADH2.

AP Practice Test

AP Practice Test

AP-Micro Microbiology: Microbial Metabolism 2