AP Biology - Anaerobic respiration and fermentation

Question 1

What is fermentation?

Answer 1

• when there is not enough oxygen being delivers fast enough a cells, the cell will rely on glycolysis for energy
• the NAD that is reduced during glycolysis cannot be deoxidized by the electron transport chain as fast as it is being reduced, and thus cells will run out of oxidized NAD+ and glycolysis will stop unless there is another pathway available
• fermentation: a cellular respiration pathway that transfers electrons from NADH to an organic acceptor molecule

Question 2

what is lactate fermentation?

Answer 2

• performed by animal muscle cells as well as some single-celled organisms
• pyruvate generate by glycolysis reacts with NADH to peroxide NAD+
  -pyruvate is converted to lactate (AKA lactic acid) the reoxidized NAD+ allows glycolysis to continue
• The lactic acid that is generated in muscles must be deoxidized to protect the tissues from the acidic environment
• oxygen is needed to allow the lactate to return to oxidative pathways to be metabolized. This amount of oxygen in called the oxygen debt

Question 3

What is ethanol fermentation?

Answer 3

• facultative anaerobes: organisms that function as well aerobically as well as anaerobically
• these organisms convert pyruvate to ethanol and carbon dioxide