AP Biology : Cellular Respiration

Study concepts, example questions & explanations for AP Biology

varsity tutors app store varsity tutors android store

Example Questions

Example Question #4 : Understand Aerobic Respiration

In the process of cellular respiration, if no oxygen is available, what is the fate of the pyruvate molecules produced during glycolysis?

Possible Answers:

Used to produce protons to increase the proton gradient

Used for lactic acid or alcoholic fermentation

Used to produce oxygen

Used to produce more glucose

Correct answer:

Used for lactic acid or alcoholic fermentation

Explanation:

If no oxygen is available, anaerobic respiration will occur. This can either be lactic acid fermentation, or alcoholic fermentation. In alcoholic or lactic acid fermentation, the pyruvate are decarboxylated and ultimately used to produce either ethanol or lactic acid, and regenerate NAD+ which will be reused for another cycle of glycolysis (2 ATP are produced for each round of glycolysis).

Example Question #2 : Understand Aerobic Respiration

Anaerobic respiration occurs when?

Possible Answers:

In the absence of 

In the presence of 

In the presence of 

In the absence of 

Correct answer:

In the absence of 

Explanation:

If no oxygen is available, anaerobic respiration will occur. This can either be lactic acid fermentation, or alcoholic fermentation. In alcoholic or lactic acid fermentation, the pyruvate are decarboxylated and ultimately used to produce either ethanol or lactic acid, and regenerate NAD+ which will be reused for another cycle of glycolysis (2 ATP are produced for each round of glycolysis).

Example Question #5 : Understand Aerobic Respiration

Where does anaerobic respiration occur in a cell?

Possible Answers:

Inner mitochondrial membrane

Cytosol

Mitochondrial matrix

Chloroplast

Correct answer:

Cytosol

Explanation:

In the absence of oxygen, pyruvate produced during glycolysis will be used for either lactic acid or alcoholic fermentation, producing lactic acid or ethanol (as waste products) and regenerating NAD+ to be used for another cycle of glycolysis. This fermentation occurs in the cytosol of the cell.

Learning Tools by Varsity Tutors