Anaerobic Respiration In Mammals

Question 1

When is anaerobic respiration needed?

Answer 1

When there is not enough oxygen present for the etc to continue and so no proton gradient is created and so ATP is produced by chemiosmosis. Also reduced NAD and FAD cant be oxidised to NAD and FAD, their levels fall very low. This means glycolysis, the link reaction or Krebs cycle cannot happen.

Question 2

Stage 1

Answer 2

In glycolysis, because there is not oxygen, glycolysis can’t take place. The cells uses the NADH produced by glycolysis to reduce the pyruvate to lactic acid

Question 3

Stage 2

Answer 3

The NADH is oxidised back to NAD which goes back through glycolysis

Question 4

Stage 3

Answer 4

The cell can produce two ATP molecules per glucose

Question 5

What is the reaction catalysed by?

Answer 5

lactate dehydrogenase

Question 6

Where does it happen

Answer 6

Entirely in the cytoplasm

Question 7

Stage 4

Answer 7

The lactic acid lowers the pH of the cell and this can cause proteins to denature, so it is transported to the liver where it is converted back to glucose, requiring oxygen (hence heavy breathing after intense exercise, oxygen debt)