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

pyruvate is converted to ethanol and lactate:

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