AP Bio U3L7 Aerobic Cellular Respiration

Multiple Choice

Hydrogen ions play a large role in aerobic and anaerobic respiration. To do this, hydrogen ions must use integral membrane proteins as they cannot directly pass through the membrane of the mitochondria. What would happen if hydrogen ions were unable to diffuse through the mitochondrial membrane?

• Pyruvate will not be produced.

• Citric acid will not be produced.

• ATP will not be produced.

• Carbon dioxide will not be produced.

Multiple Choice

The diagram below represents the electron transport chain composed of four protein complexes and two electron transport proteins, cytochrome C (cyt C) and ubiquinone (Q). Based on your understanding of this step, where do the electrons traversing the membrane come from and where do they ultimately end up? 

• The electrons are emitted by ubiquinone and are, in turn, finally accepted by water.

• The electrons are emitted by NADH and FADH2 and are finally accepted by oxygen, which ultimately forms water.

• The electrons are released by NADH and FADH2, and in turn, are finally accepted by water.

• The electrons are given off by water and finally accepted by NAD+ and FAD to produce NADH and FADH2.

Open Ended

Aerobic cellular respiration is a complex biochemical pathway that involves four stages. Based on this understanding:

(a) List the total number of ATP produced after completion of the Krebs cycle and oxidative phosphorylation.

(b) Explain the linking stage of pyruvate oxidation, which connects glycolysis to the Krebs cycle.

(c) Explain how the formation of a proton gradient powers ATP synthesis.

Respond in 4 to 6 complete sentences.