Anaerobic Respiration

• Oxygen absence; no final electron acceptor, reduced NAD not re-oxidises, Krebs cycle and Link reaction stop, so no oxidative phosphorylation or ETC; no ATP production
• Simplified diagram

  A) Aerobic

  B) 38 ATP

  C) 1

  D) glucose

  E) glucose

  F) glycolysis

  G) ATP

  H) pyruvate

  I) Acetyl coenzyme A

  J) Krebs cycle

  K) CO_2

  L) oxidative phosphorylation

  M) O_2

  N) H_2O

  O) ATP

  P) Anaerobic

  Q) 2 ATP

  R) Ethanol

  S) CO_2

  T) lactate

  
• Little ATP made in glycolysis, but for this to happen reduced NAD must be re-oxidised and recycled; two mechanisms for this: alcoholic or lactic fermentation
• • Alcoholic Fermentation: Occurs in yeast cells and green plant roots when in waterlogged/anoxic conditions soil; ethanol is toxic and if allowed to build up will eventually kill yeast cells; an important process exploited in the production of beer and wine

  A) glucose

  B) triose phosphate

  C) Oxidised NAD

  D) reduced NAD

  E) pyruvate

  F) C_3H_4O_3

  G) CO_2

  H) ethanal

  I) CH_3CHO

  J) alcohol dehydrogenase

  K) ethanol

  L) C_2H_5OH

  M) reduced NAD

  N) Oxidised NAD

  O) ethanol

  P) pyruvate

  Q) Oxidised NAD

  R) glycolysis

  
• Lactic Fermentation: Occurs in mammalian skeletal muscle and erythrocytes; lactate will build up in muscles during heavy exercise, causing muscle fatigue, as lactate is toxic

  A) glucose

  B) triose phosphate

  C) Oxidised NAD

  D) reduced NAD

  E) pyruvate

  F) C_3H_4O_3

  G) lactate dehydrogenase

  H) lactate

  I) C_3H_6O_3

  J) reduced NAD

  K) Oxidised NAD

  L) lactate

  M) pyruvate

  N) Oxidised NAD

  O) glycolysis

  
• Always starts with glycolysis and so if you are asked to describe anaerobic respiration in mammals or yeast, you must describe details of glycolysis first
• COMPARISON OF ANAEROBIC RESPIRATION IN YEAST AND MAMMALS

  A) NAD

  B) NAD

  C) Ethanal

  D) Pyruvate

  E) Yes

  F) No

  G) Yes

  H) Yes

  I) Yes

  J) Yes

  K) Ethanol

  L) CO_2

  M) Lactic Acid

  N) alcohol dehydrogenase

  O) pyruvate decarboxylase

  P) lactate dehydrogenase