Can all cells carry out glycolysis
- yes
- >red blood cells depend on glycolysis for energy because they lack mitochondria
What is the end result of glycolysis
-convert glucose into two pyruvate molecules
Contrast hexokinase and glucokinase
Hexokinase
- > present in most tissues
- > low Km(reaches maximum velocity at low [glucose])
- > inhibited by glucose 6-phosphate
Glucokinase
- > present in hepatocytes and pancreasing B-islet cells
- > high Km(acts on glucose proportionally to its concentration)
- > induced by insulin in hepatocytes
What is the rate limiting for glycolysis
-phosphofructokinase 1
How does ATP, citrate and AMP relate to PFK-1?
- high levels of ATP and citrate inhibit PFK-1
- high levels of AMP activate PFK-1
How does insulin, and glucagon relate to PFK-1?
-insulin activates PFK-1 and glucagon inhibits it
What is the role of PFK-2?
- converts fructose-6 phosphate to fructose 2,6-biphosphate
- even with high levels of ATP, PFK 2 allows for the continued activation of PFK 1
How does fructose 1,6-biphosphate relate to pyruvate kinase
- it results in feed-forward reaction
- >so the product formation of fructose 1,6-biphosphate stimulates pyruvate kinase
What are the three irreversible enzymes of glycolysis
- glucokinase or hexokinase
- PFK-1
- Pyruvate kinaase
When does fermentation occur? Relate it to oxygen levels
-in the absence of oxygen, fermentation will occur
How does fermentation allow for glycolysis to keep going
- it oxidizes NADH to NAD+
- > glycolysis needs NAD+ to continue working
- > so fermentation provides glycolysis with that NAD+
- note when NADH is oxidized to NAD+
- > pyruvate is reduced to lactate by lactate dehydrogenase
How does fermentation differ in yeast cells
- in yeast cells instead of producing lactate, pyruvate is reduced to produce carbon dioxide and ethanol
- again NAD+ is replenished
What is DHAP used for in hepatic and adipose tissue
- it is used for triacylglycerol synthesis
- DHAP is formed from 1,6-biphosphate
- > it is then isomerized to glycerol 3-phosphate which can then be converted to glycerol
- > glycerol is the backbone of triacylglycerol
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Chapter 2.18
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Chapter 2.27
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Chapter 2.36
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Chapter 2.41
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Chapter 2.57
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Chapter 3.117
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Chapter 3.25
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Chapter 3.319
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Chapter 4.17
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Chapter 4.25
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Chapter 4.33
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Chapter 4.413
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Chapter 5.111
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Chapter 5.217
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Chapter 5.37
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Chapter 6.110
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Chapter 6.28
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Chapter 6.310
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Chapter 6.48
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Chapter 6.514
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Chapter 7.111
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Chapter 7.213
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Chapter 7.310
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Chapter 7.47
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Chapter 7.56
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Chapter 9.15
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Chapter 9.213
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Chapter 9.33
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Chapter 9.44
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Chapter 9.511
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Chapter 9.614
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Chapter 9.74
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Chapter 12.12
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Chapter 12.25
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Chapter 12.32
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Chapter 12.49
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Chapter 12.515
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Chapter 12.610
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Chapter 10.16
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Chapter 10.212
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Chapter 10.310
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Chapter 8.15
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Chapter 8.212
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Chapter 8.32
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Chapter 8.43
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Chapter 10.43
