anaerobic respiration Flashcards
When does anaerobic respiration occur
When oxygen isn’t present
What happens to the electron transport chain if oxygen isn’t present
Oxygen is unable to act as the final electron acceptor as so electron transport chain doesn’t function
What happens to proton gradient in absence of oxygen
Proton gradient across inner mitochondrial membrane cannot be maintained as hydrogen ions build up in the matrix as they are not removed by oxygen to form water or transported across membrane by electron carrier proteins
What is the only respiratory pathway that can occur without oxygen
Glycolysis
What is required in order for glycolysis to continue
Red NAD must be re-oxidised so it can return to glycolysis and accept another hydrogen atom
Why cant red NAD be re-oxidised if oxygen is not present
Cannot be re-oxidised at electron transport chain so another pathway is required
Where does anaerobic respiration occur
Sarcoplasm of muscle cell
Which pathway is used to re-oxidise NAD in the absence of oxygen
Lactate fermentation pathway
Describe the lactate fermentation pathway
Molecule of pyruvate accepts the hydrogen atom from reduced NAD to make oxidised NAD.
This causes the pyruvate to become lactate
This reaction is catalysed by enzyme lactate dehydrogenase
What is an issue with the lactate produced
The lactate is acidic so if it is not removed from muscle tissue it can lower the pH which may inhibit enzymes
What is done to try to prevent lowering of the pH
Lactate transported to liver where it is converted to pyruvate when more oxygen is available. Also released into urine and sweat
What allows the cell to control the rate of aerobic respiration
The products of one reaction act as substrates for the next
What is end point inhibition
Controlling rate of respiration - high ATP concentrations in cytoplasm inhibit the early enzymes in glycolysis, preventing ATP synthesis by substrate level phosphorylation
