Anaerobic respiration

How is ethanol produced in plants and some microorganisms?

The pyruvate molecule formed at the end of glycolysis is decarboxylated (loses a CO2 molecule) which produces ethanal

Ethanal is reduced (accepts hydrogen) from NADH to produce ethanol

Pyruvate + reduced NAD → ethanol + carbon dioxide + oxidised NAD

What can the oxidised NAD produced be used for?

Further glycolysis

What are the consequences of anaerobic respiration?

There’s no final electron acceptor - electron transport chain doesn’t work

Without the formation of water, the H+ gradient will be lost so ATP production will be reduced

Reduced FAD and NAD aren’t oxidised by electron carrier

No link reaction

No Krebs cycle

How is lactate produced in animals?

NADH from glycolysis accumulates

Pyruvate takes up the 2 hydrogen atoms (is reduced by the enzyme lactate dehydrogenase)

Pyruvate + reduced NAD → lactate + oxidised NAD

What happens to the lactate that is produced?

It can be oxidised back to pyruvate (using oxygen) - can be channelled into the link reaction/Krebs cycle for ATP production

Can be converted to glycogen for storage in the liver

The oxidation of lactate back to pyruvate requires what?

Extra oxygen - oxygen debt created

Where does anaerobic respiration take place?

The cytoplasm