C1: Anaerobic respiration Flashcards
Define Anaerobic respiration
The breakdown of molecules in the absence of oxygen, releasing reletively little energy, making a small amount of ATP by substrate level phosphorylation
Describe why Anaerobic respiration takes place
Absence of oxygen means there is no final electron acceptor to form water.
ETC cannot function. there is no oxidative phosphorylation so no ATP formed . Reduced NAD and reduced FAD cannot be reoxidised therefore cannot accept hydrogen atoms so the link reaction and krebs cycle do not take place.
what stage of aerobic respiration occurs in anaerobic respiration
Glycolysis
Describe anaerobic respiration in Animals
Glycolysis takes place forming Pyruvate which accepts hydrogens from the reduced NAD also formed, this produces lactic acid and oxidised NAD (NAD or NAD+)
NAD+ can then accept hydrogen atoms formed in glycolysis and the cycle continues.
What are the products of anaerobic respiration in animals
Lactic acid (lactate)
What happens if oxygen subsiquently becomes available in animals during anaerobic respiration
The latic acid can be respired to CO2 and H2O which releases energy
Describe Anaerobic respiration in Plants
Glycolysis occurs
Pyruvate is decarboxylated to Ethanal
Ethanal is reduced and accepts Hydrogens from reduced NAD (so NAD is oxidised) to form Ethanol and NAD+
NAD+ can then accept hydrogens formed in glycolysis and be reduced so the cycle repeats
Ethanol accumulates ( to potentailly toxic levels) in the cell
What are the products of anaerobic respiration in plants
Ethanol
CO2
What happens if oxygen subsiquently becomes available in plants during anaerobic respiration
Pathway is not reversible so ethanol is not broken down
provide an example of when a plant undergo anaerobic respiration
In the roots due to water logged soil
When might an animal undergo anaerobic respiration
Muscle cells duing vigerous exercise
How many ATP is produced per glucose molecule in anaerobic respiration
2 ATP (by substrate level phosphorylation)
