Bioenergetics Flashcards
Acetyl CoA is the activated form of ___
Acetate
What are the 3 energy sources Acetyl CoA can be generated from?
(1) Carbs Glucose -> 2 Pyruvate -> 2 Acetyl CoA (2) Lipids TAG -> FAs -> Acetyl CoA (via B oxidation) Oxidation of ketone bodies -> Acetyl CoA (3) Proteins Breakdown into AAs -> Acetyl CoA
___ form of PDC is active
Dephosphorylated
___ form of PDC is inactive
Phosphorylated
Where does phosphorylation occur in PDC?
Coenzyme TTP of E1 complex
What are the 5 coenzymes of the PDC?
- Thiamine Pyrophosphate (TPP)
- Coenzyme A (CoA)
- Lipoic Acid
- Flavin Adenine Dinucleotide (FAD)
- NAD
What vitamin is TPP derived from?
B1 (thiamine)
What vitamin is CoA derived from?
B5 (panthothenic acid)
What vitamin is Lipoic Acid derived from?
None
What vitamin is FAD derived from?
B2 (riboflavin)
What vitamin is NAD derived from?
B3 (niacin)
What does the enzyme Pyruvate Dehydrogenase Kinase (PDK) do to PDC?
Phosphorylates it = inactive
What does the enzyme Pyruvate Dehydrogenase Phosphatase (PDP) do to PDC?
Dephosphorylates it = active
What are the 3 activators of PDK?
- Acetyl CoA
- NADH
- ATP
What are the 4 inhibitors of PDK?
- Pyruvate
- CoA
- NAD
- ADP
What are the 2 activators of PDP?
- Ca2+
- Mg2+
What are the 2 direct inhibitors of the E1 complex of PDC?
- Acetyl CoA
- NADH
In a phosphatase deficiency…
(1) PDC is always in ___ form
(2) Glucose -> ___ rather than Acetyl CoA
(3) Results in constant ___ acidosis
(1) phosphorylated (inactive!)
(2) Lactate
(3) Lactic Acidosis (high blood levels of lactic acid)
What system is affected the most by a phosphatase deficiency?
Central Nervous System
Intake of what AA should be restricted in a phosphatase deficiency?
Alanine
What happens if there is insufficient oxygen in muscle cells for further oxidation of pyruvate?
NAD is regenerated from NADH by reduction of pyruvate to lactic acid via Lactate Dehydrogenase Enzyme
What type of diet is recommended in a phosphatase deficiency?
Ketogenic
helps minimize pyruvate formation
What are the 3 rate irreversible steps/enzymes of the CAC?
(1) Citrate Synthase
(2) Isocitrate Dehydrogenase
(3) α-Ketoglutarate Dehydrogenase
What enzyme results in the formation of GTP in the CAC?
Succinate Thiokinase
What is the rate limiting step of CAC?
Isocitrate -> α-Ketoglutarate
Isocitrate Dehydrogenase
Which enzyme in the CAC requires the same 5 coenzymes as the PDC to function?
α-Ketoglutarate Dehydrogenase
When cellular ATP levels are low, the activity of TCA cycle is ____
Increased
When cellular ATP levels are high, the activity of TCA cycle is ___
Decreased / Inhibited
mitochondrial ETC inhibition
Anaplerotic Reacations
- “fill up” reactions
- provide intermediates to replenish the TCA cycle
What are the two major anaplerotic reactions?
- Degradation of AAs (produces either TCA cycle intermediates or pyruvate)
- Carboxylation of pyruvate (ie synthesis of OAA by decarbox of pyruvate)
(1) Degradation of what 4 AAs replenish α-Ketoglutarate? (2) What molecule are the 4 AAs turned in to before they can replenish α-Ketoglutarate?
(1) Glutamine, Histidine, Arginine, Proline (GHAP) (Go Poke His Arse)
(2) Glutamate
(1) Degradation of what 4 AAs replenish Succinyl CoA? (2) What molecule are the 4 AAs turned in to before they can replenish Succinyl CoA?
(1) Threonine, Isoleucine, Methionine, Valine (TIM V)
(2) Propionyl CoA
(Thor Met Val Inside College Pub)
(1) Degradation of what 3 AAs replenish Fumarate?
(1) Phenylalanine, Aspartate, Tyrosine (PAT)
Try Phucking ASaP
(1) Degradation of what AA replenishes OAA?
(2) What molecule is the AA turned in to before it can replenish OAA?
(1) Asparagine
(2) Aspartate
What is the path taken by Pyruvate through the CAC when it feeds into lipid synthesis?
Pyruvate -> Acetyl CoA -> Citrate -> Citrate -> Acetyl CoA -> FAs, Isoprenoids