Anaerobic Respiration

• • 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

  
• Anaerobic Respiration

  • No O_2; no final e- acceptor, no re-oxidisation, Krebs cycle + Link reaction stop, no oxidative phosphorylation or ETC
  • Little ATP from glycolysis, but reduced NAD must be re-oxidised + recycled; 2 mechanisms: alcoholic or lactic fermentation
  • Alcoholic Fermentation
  • Yeast cells + green plant roots when in waterlogged/anoxic conditions
  • Ethanol is toxic + let build up eventually kill yeast cells; process exploited in beer/wine production
  • Lactic Fermentation
  • Mammalian skeletal muscle + erythrocytes
  • Lactate build up in muscles during heavy exercise; cause muscle fatigue, lactate is toxic
  • Reversible, lactate metabolised when more O_2 available
  • Cori cycle: Lactate removed from muscles, liver takes recycling metabolic burden + stop dangerous pH drop
  • Cannot be sustained long; uses too much ATP
  • O_2 needed to fully oxidise lactate is called O_2 debt
  • Starts with glycolysis