bio 6B

Question 1

what is anaerobic fermentation?

Answer 1

a fast metabolic pathway that occurs in the absence of oxygen (and creates 2 ATP per glucose molecule). it involves glycolysis followed by further reactions that convert pyruvate into lactic acid in animals and ethanol + CO2 in yeasts. it also involves one or two extra reactions to recycle NADH to create a steady supply of NAD+

Question 2

what would happen in anaerobic conditions if anaerobic fermentation could not occur?

Answer 2

protons and electrons could no longer bond with oxygen to create water and this means that NADH and FADH2 could no longer unload and be recycled, leading to an increase of NADH and FADH2 while the Krebs cycle and ETC stop

Question 3

what is the process of anaerobic fermentation in animals?

Answer 3

• occurs in the cytosol
  when oxygen availability is limited, animals undertake lactic acid fermentation after glycolysis (pyruvate breaks down into lactic acid and cycles NADH back into NAD+ for reuse)

Question 4

what is the process of anaerobic fermentation in yeasts?

Answer 4

• occurs in the cytosol
  when oxygen availability is limited, yeasts undertake ethanol fermentation after glycolysis (pyruvate creaks down into ethanol + CO2 and cycles NADH back into NAD+ for reuse)

Question 5

is anaerobic fermentation sustainable?

Answer 5

no, as it could not continue indefinitely due to the toxic-build up of lactic acid or ethanol