Anaerobic respiration

Question 1

What happens to pyruvate in yeasts, under anaerobic conditions?

Answer 1

Pyruvate decarboxylase forms acetaldehyde, which uses alcohol dehydrogenase to form NAD+ from NADH, and ethanol

Question 2

What happens to pyruvate in mammalian muscle, under anaerobic conditions?

Answer 2

Lactate dehydrogenase and NADH is used to form lactate, and NAD+.

Question 3

What happens to lactate formed in the muscle?

Answer 3

It is transported in blood to the liver, for conversion back to glucose (Cori cycle). So, this glucose can be metabolised in the muscle to lactate again.

Question 4

What is the purpose of anaerobic respiration?

Answer 4

NAD+ is regenerated, so anaerobic glycolysis can continue to generate ATP.

Question 5

Why is it important that glycolysis can continue with NAD+?

Answer 5

Dehydrogenation of glyceraldehyde-3-phosphate to form 1,3-bisphosophoglycerate, which then forms 3-phosphoglycerate. This step forms ATP