MCAT Metabolic Pathways
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1. What are the aerobic and anaerobic functions of glycolysis? Where does it
occur?: Aerobic: To convert glucose to pyruvate and ATP. Pyruvate can be burned for energy (TCA) or converted to
fat (fatty acid synthesis).
Anaerobic: ATP production. Recycle NADH by making lactate.
Occurs in the cytoplasm of all living cells
2. Glycolysis regulation (signals): Primary signals:
- Insulin turns on
- Glucagon turns off
- Epinephrine turns on in muscle, off in liver
- Phosphorylation turns off in liver, on in muscles
Secondary signals:
- activated by low ATP and
Fructose 2,6-P
- inhibited by low glucose and high ATP
3. What are the major glycolysis connections?: - Glucose in, pyruvate or lactate out.
- Glucose 6-phosphate to glycogen (reversible).
- Glucose 6-phosphate to pentose phosphates (not reversible).
- Pyruvate to TCA via acetyl-CoA (not reversible).
- Pyruvate to fat via acetyl-CoA (not reversible).
4. Glycolysis Equation and ATP Yields (anaerobic): Fermentation: Partial oxidation of metabolite
(glucose) to pyruvate
Glucose 2ADP 2Pᵢ ’2ATP 2 lactate
(no NAD⁺)
Yield:
1 glucose ’2ATP 2 lactate
5. Fermentation: Purpose: regenerate NAD⁺ for glycolysis. 1 NAD⁺ is net for every pyruvate in a oxidation-re-
duction reaction: reduce pyruvate, oxidize NADH
1/6
, MCAT Metabolic Pathways
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- 2 net ATP per glucose
- Pyruvate reduced to either alcohol (bacteria) or lactate (humans)
6. Glycolysis Equation and ATP Yields (aerobic): Glucose 2ADP 2Pᵢ 2NAD⁺ ’2 pyruvate 2ATP
2NADH 2H⁺
Yield:
1 glucose ’2ATP 2NADH 2 pyruvate
7. Glycolysis steps: "Goodness Gracious, Fred's Father Did Go By Picking Pumpkins (to) PrEPare Pies"
Glucose
Glucose-6-P
Fructose-6-P
Fructose-1,6-diP
Dihydroxyacetone-P
Glyceraldehyde-P
1,3- Biphosphoglycerate
3-Phosphoglycerate
2-Phosphoglycerate (to)
Phosphoenolpyruvate [PEP]
Pyruvate
Did = Dihydroxyacetone phosphate
By = 1,3-bisphosphoglycerate
PrEPare = PEP (phosphoenolpyruvate)
Pie = Pyruvate
'Did', 'By' and 'Pies' tell you the first part of those three: di-, bi-, and py-. 'PrEPare' tells location of PEP in the process.
8. Glycolysis pathway mnemonic: Gross Guys Fμck Big Boobs but Generous and Dreamy Boys Prefer
Pretty, Poised Petite Ladies
10 steps:
Glucose
2/6
Study online at https://quizlet.com/_8ltbtv
1. What are the aerobic and anaerobic functions of glycolysis? Where does it
occur?: Aerobic: To convert glucose to pyruvate and ATP. Pyruvate can be burned for energy (TCA) or converted to
fat (fatty acid synthesis).
Anaerobic: ATP production. Recycle NADH by making lactate.
Occurs in the cytoplasm of all living cells
2. Glycolysis regulation (signals): Primary signals:
- Insulin turns on
- Glucagon turns off
- Epinephrine turns on in muscle, off in liver
- Phosphorylation turns off in liver, on in muscles
Secondary signals:
- activated by low ATP and
Fructose 2,6-P
- inhibited by low glucose and high ATP
3. What are the major glycolysis connections?: - Glucose in, pyruvate or lactate out.
- Glucose 6-phosphate to glycogen (reversible).
- Glucose 6-phosphate to pentose phosphates (not reversible).
- Pyruvate to TCA via acetyl-CoA (not reversible).
- Pyruvate to fat via acetyl-CoA (not reversible).
4. Glycolysis Equation and ATP Yields (anaerobic): Fermentation: Partial oxidation of metabolite
(glucose) to pyruvate
Glucose 2ADP 2Pᵢ ’2ATP 2 lactate
(no NAD⁺)
Yield:
1 glucose ’2ATP 2 lactate
5. Fermentation: Purpose: regenerate NAD⁺ for glycolysis. 1 NAD⁺ is net for every pyruvate in a oxidation-re-
duction reaction: reduce pyruvate, oxidize NADH
1/6
, MCAT Metabolic Pathways
Study online at https://quizlet.com/_8ltbtv
- 2 net ATP per glucose
- Pyruvate reduced to either alcohol (bacteria) or lactate (humans)
6. Glycolysis Equation and ATP Yields (aerobic): Glucose 2ADP 2Pᵢ 2NAD⁺ ’2 pyruvate 2ATP
2NADH 2H⁺
Yield:
1 glucose ’2ATP 2NADH 2 pyruvate
7. Glycolysis steps: "Goodness Gracious, Fred's Father Did Go By Picking Pumpkins (to) PrEPare Pies"
Glucose
Glucose-6-P
Fructose-6-P
Fructose-1,6-diP
Dihydroxyacetone-P
Glyceraldehyde-P
1,3- Biphosphoglycerate
3-Phosphoglycerate
2-Phosphoglycerate (to)
Phosphoenolpyruvate [PEP]
Pyruvate
Did = Dihydroxyacetone phosphate
By = 1,3-bisphosphoglycerate
PrEPare = PEP (phosphoenolpyruvate)
Pie = Pyruvate
'Did', 'By' and 'Pies' tell you the first part of those three: di-, bi-, and py-. 'PrEPare' tells location of PEP in the process.
8. Glycolysis pathway mnemonic: Gross Guys Fμck Big Boobs but Generous and Dreamy Boys Prefer
Pretty, Poised Petite Ladies
10 steps:
Glucose
2/6
