Glycolysis Flashcards
Aerobic Glycolysis
O2 dependent, reoxidising NADH to NAD+ to generate ATP.
Anerobic Glycolysis
O2 independent, producing ATP and NADH.
How much ATP do the two types of glycolysis produce?
Anaerobic produces 2 ATP whilst Aerobic produces 32 ATP.
Why is the final step of glycolysis is ATP produced?
As phosphoenolpyruvate is unstable, pyruvate kinase catalysed removal of its phosphoate group, forming two pyruvate.
What is the fate of pyruvate determined by?
The cells microenvrionment; lacking mitochondria means energy demand increases to exceed rate that OP provides sufficient ATP, so LDH converts pyruvate into lactate.
How is lactate utilised?
The conversion of pyruvate into lactate regenerates NAD+ from NADH, NAD+ being a cofactor necessary to maintain flow of glucose through glycolysis.
What is the destiny of pyruvate?
Translocation intro mitochondria as a fuel input for CAC, driving ATP production of OP and other pathways
Where does pyruvate derive from?
Glycolysis.
What is pyruvate critical for?
Mitochondrial ATP generation, and driving various pathways that intersect the CAC.
What are the three pathways generating Pyruvate?
Lactate oxidation, transamination of alanine and glycolysis.
How is passage of pyruvate into the mitochondria mediated?
The Mitochondrial Pyruvate Complex on the inner and outer membranes.
What two substrates are pyruvate converted into in the mitochondrial matrix?
Acetyl-COA or Oxaloacetate
Oxaloacetate
A CAC intermediated reacting with Acetyl-COA to form citrate via citrate synthase.
What is the function of oxaloacetate after conversion from pyruvate?
Entry into the CAC or conversion to phosphoenolpyruvate as a part of gluconeogenesis.
What facilitates conversion of oxolacetate to phosphoenolpyruvate?
Phosphoenolpyruvate Carboxykinase
What is the major cytosilic fate of pyruvate produced from PK?
Reversible reaction into lactate.
What is a characertisitc of intense exercise?
Increased energy requirements for continued muscle contraction that exceeds mitochondrial capacity for ATP production by OP.
How does the cell cope when energy requirements exceed mitochondrial ATP capacity?
Glycolytic ATP production is hindered when NAD+ levels diminish and NADH accumulates, as glycolysis required NAD+; so LDH supports glycolysis by NAD+ regeneration, where glycolysis supports energy demands quicker than OP can.
What is the major form of ATP production during exercise for muscles?
Anaerobic glycolysis as oxygen is low and ATP is high.. opposed to the slower OP.
What does LDH do in anaerobic glycolysis during exercise?
Oxidises pyruvate, coupled with NADH to yield NAD+ and lactate.
What does lactate formed from LDH do?
It can be exported from the cell to liver for conversion to glucose, or convert back to pyruvate.
What does LDH do to lactate in the liver?
LDH converts it back into pyruvate, so it can support glycolysis and gluconeogenesis in the Cori Cycle.
The Cori Cycle.
Here, liver lactate is reconverted into pyruvate, and used gluconeogenesis, where resulting glucose resupplies energy-deficient muscle.
How might lactate alternatively be supplied?
Alanine aminotransferase catabolises amino acids
