ACS BIOCHEMISTRY REVIEW|VERIFIED QUESTIONS AND CORRECT DETAILED
ANSWERS|RATED AND GRADED A+ NEW UPDATE| 2026/2027
ATP Counting - ANSWER✔ Glycolysis:
- 2 ATP
- 2 NADH (cytoplasm) = 3 ATP
Pyruvate DH
- 2 NADH (mito) = 5 ATP
TCA (x2 from 1 glucose)
- 3 NADH (mito) = 15 ATP
- 1 FADH2 = 3 ATP
- 1 GTP = 2 ATP
Pyruvate Dehydrogenase - ANSWER✔ 1. Pyruvate + TPP
2. TPP + lipoamide
3. CoA + lipoamide = acetyl CoA
4. renerate lipoamide + NADH
Mercury and Arsenic Poisoning - ANSWER✔ Chelates to lipoamide
to remove put in stronger chelating agent so mercury doesnt bind
Regulation of PDH - ANSWER✔ 1. Phosphorylate PDH inactivates
(high ATP - dont want cycle turned on)
TCA Cycle - ANSWER✔ Citrate (Aconitase)
Isocitrate (Isocitrate DH)
a - Ketoglutarate (a-Ketoglutarate DH complex)
,Succinyl CoA (Succincyl CoA synthetase)
Succinate (Succinate DH)
Fumarate (Fumarase)
Malate (Malate DH)
Oxaloacetate (Citrate Synthase)
Diseases of TCA cycle - ANSWER✔ 1. Hypoxia induced factor I - low O2 levels and therefore harder to
get into glycolysis
2. Enzyme deficiencies - need for SDH and PDH
3. Beriberi - thiamine deficiency = bone deformities
4. Mercury and Arsenic - chelaters for dihyrdolipoamides
Regulation points - ANSWER✔ - Isocitrate --> a-Ketoglutarate
ATP and NADH regulate this cycle if present
ADP regulates by being absent
Branching off - ANSWER✔ citrate --> fatty acids and steroids
a-Ketoglutarate --> glutamate and amino acids
Succinyl CoA --> porphorins
Oxaloacetate --> amino acids, glucose
Glyoxylate cycle - ANSWER✔ Support plants to live off fat and oil from storage
convert succinate into glucose
not as efficient
, /Use acetate --> acetyl CoA no glycolysis
/succinate&oxaloacetate --> glucose
/through gluconeogenesis = 2 Acetyl CoA = 1 NADH
/isocitrate lyase --> glyoxylate --> Malate synthase
Delta G
Eo - ANSWER✔ Change in gibbs free energy
Electron transfer potential
Complexes of ETC - ANSWER✔ 1. NADH Q Oxidoreductase
2. Succinate Q Reductase
3. Q Cytochrome c reductase
4. Cytochrome c oxidase
Regulate TCA Cycle
ATP Counting - ANSWER✔
Complexes of ETC (1) - ANSWER✔ NADH Q Oxidoreductase
NADH converted to NAD to add electrons to FMN - electrons are transferred down [4fe-4s] clusters
2 protons are added to convert ubiquinone to ubiquinol to Q pool
4 protons are pumped through
Complexes of ETC (2) - ANSWER✔ Succinate Q Reductase
succinate convert to fumarate
electrons are transfer FADH2 --> FAD through fe-s clusters
2 protons convert ubiquinone to ubiquinol
SDH is part of TCA cycle
ANSWERS|RATED AND GRADED A+ NEW UPDATE| 2026/2027
ATP Counting - ANSWER✔ Glycolysis:
- 2 ATP
- 2 NADH (cytoplasm) = 3 ATP
Pyruvate DH
- 2 NADH (mito) = 5 ATP
TCA (x2 from 1 glucose)
- 3 NADH (mito) = 15 ATP
- 1 FADH2 = 3 ATP
- 1 GTP = 2 ATP
Pyruvate Dehydrogenase - ANSWER✔ 1. Pyruvate + TPP
2. TPP + lipoamide
3. CoA + lipoamide = acetyl CoA
4. renerate lipoamide + NADH
Mercury and Arsenic Poisoning - ANSWER✔ Chelates to lipoamide
to remove put in stronger chelating agent so mercury doesnt bind
Regulation of PDH - ANSWER✔ 1. Phosphorylate PDH inactivates
(high ATP - dont want cycle turned on)
TCA Cycle - ANSWER✔ Citrate (Aconitase)
Isocitrate (Isocitrate DH)
a - Ketoglutarate (a-Ketoglutarate DH complex)
,Succinyl CoA (Succincyl CoA synthetase)
Succinate (Succinate DH)
Fumarate (Fumarase)
Malate (Malate DH)
Oxaloacetate (Citrate Synthase)
Diseases of TCA cycle - ANSWER✔ 1. Hypoxia induced factor I - low O2 levels and therefore harder to
get into glycolysis
2. Enzyme deficiencies - need for SDH and PDH
3. Beriberi - thiamine deficiency = bone deformities
4. Mercury and Arsenic - chelaters for dihyrdolipoamides
Regulation points - ANSWER✔ - Isocitrate --> a-Ketoglutarate
ATP and NADH regulate this cycle if present
ADP regulates by being absent
Branching off - ANSWER✔ citrate --> fatty acids and steroids
a-Ketoglutarate --> glutamate and amino acids
Succinyl CoA --> porphorins
Oxaloacetate --> amino acids, glucose
Glyoxylate cycle - ANSWER✔ Support plants to live off fat and oil from storage
convert succinate into glucose
not as efficient
, /Use acetate --> acetyl CoA no glycolysis
/succinate&oxaloacetate --> glucose
/through gluconeogenesis = 2 Acetyl CoA = 1 NADH
/isocitrate lyase --> glyoxylate --> Malate synthase
Delta G
Eo - ANSWER✔ Change in gibbs free energy
Electron transfer potential
Complexes of ETC - ANSWER✔ 1. NADH Q Oxidoreductase
2. Succinate Q Reductase
3. Q Cytochrome c reductase
4. Cytochrome c oxidase
Regulate TCA Cycle
ATP Counting - ANSWER✔
Complexes of ETC (1) - ANSWER✔ NADH Q Oxidoreductase
NADH converted to NAD to add electrons to FMN - electrons are transferred down [4fe-4s] clusters
2 protons are added to convert ubiquinone to ubiquinol to Q pool
4 protons are pumped through
Complexes of ETC (2) - ANSWER✔ Succinate Q Reductase
succinate convert to fumarate
electrons are transfer FADH2 --> FAD through fe-s clusters
2 protons convert ubiquinone to ubiquinol
SDH is part of TCA cycle
