IMED1003 Lecture Notes - Lecture 9: Lactate Dehydrogenase, Ribose, Hemolytic Anemia
IMED1003 Notes: Anaerobic Metabolism and Pentose Phosphate Pathway
Learning Outcomes:
-Describe the alternate pathways of anaerobic metabolism (human and yeast)!
-Explain the purpose of generating lactate!
-Describe the Cori cycle & explain its role in the body!
-Have a basic understanding of the Pentose Phosphate Pathway and its roles in cells!
To Know:
-Production of ethanol: only when no O2!
-Glycolysis occurs in cytosol!
Anaerobic Metabolism:
-Occurs only absence of oxygen. fermentation occurs !
-When there is no oxygen, NADH accumulates = inhibits pyruvate oxidation!
-Pyruvate in turn accumulates -> converted to lactate/ethanol!
-Humans: Pyruvate to lactate
-Yeast: Pyruvate to ethanol
Absence of Oxygen:
-Absence of oxygen = can’t undergo TCA Cycle!
-But still need ATP, so need NAD+ for glycolysis!
-Glycolysis cannot continue unless have NAD+ which is needed!
-Thus, pyruvate accumulate, producing ethanol/lactate!
-NADH needed to ‘carry’ H+ ions away!
-Accumulation of (H+) -> lactate!
-Acidosis!! (BUT with NAD+ regeneration = can produce ATP)!
Anaerobic Exercise:
-During high intensity exercise (eg. sprint) = muscle’s mitochondria O2 demand exceeds
capacity of blood to deliver it (supply)!
-Temporarily: stored energy (ATP/creatine-P) used (but will be depleted after less than a
minute)!
-Stored glucose (glycogen) burnt via glycolysis -> produce lactate -> can get some ATP
(also cannot be sustained)!
-Accumulation of lactate metabolised because too acidic!
-Requires oxygen to metabolise lactate -> leads to oxygen debt !
Aerobic Exercise:
-During low intensity exercise (eg. jogging) = capacity of blood increases !
--> can delivery oxygen to muscle mitochondria !
-Where has relatively lower demand!
-Mitochondrial volume and ETC components start increasing!
Document Summary
Imed1003 notes: anaerobic metabolism and pentose phosphate pathway. Describe the alternate pathways of anaerobic metabolism (human and yeast) Describe the cori cycle & explain its role in the body. Have a basic understanding of the pentose phosphate pathway and its roles in cells. Production of ethanol: only when no o2. Occurs only absence of oxygen. fermentation occurs. When there is no oxygen, nadh accumulates = inhibits pyruvate oxidation. Pyruvate in turn accumulates -> converted to lactate/ethanol. Absence of oxygen = can"t undergo tca cycle. But still need atp, so need nad+ for glycolysis. Glycolysis cannot continue unless have nad+ which is needed. Nadh needed to carry" h+ ions away. Acidosis!! (but with nad+ regeneration = can produce atp) During high intensity exercise (eg. sprint) = muscle"s mitochondria o2 demand exceeds capacity of blood to deliver it (supply) Temporarily: stored energy (atp/creatine-p) used (but will be depleted after less than a minute)
