TCA cycle Flashcards
Three stages of energy metabolism?
Glycolysis
Citric acid cycle
Electron transfer chain
Acetyl-CoA sources
Fatty acid palmitate
Ketone body acetoacetate
Sugar glucose
Pyruvate
Amino acid alanine
Ethanol
Overall reaction of TCA cycle
CH3COCOOH (pyruvate) + 3H2O -> 3CO2 + 10H
Purpose of TCA cycle
Reducing electron carriers for the electron transport chain
TCA is amphibolic. What does this mean?
Intermediates are used in both catabolism and anabolism
Regulating biosynthesis of citrate from Acetyl-CoA
Citrate (too much, it regulates itself)
Pyruvate dehydrogenase regulation (chemicals needed)
Kinase: becomes inactive
Phosphatase: becomes active
Essentially whether a phosphate is added or not
Energetics of TCA cycle
Positive for citrate to isocitrate and for malate to oxaloacetate.
Vitamins in pyruvate dehydrogenase complex and their roles
Pantothenic acid: used to synthesize coenzyme A, can be used in acetyl CoA
Vitamin B1: used to create thiamine diphosphosphate
Niacin: used to create NAD+/NADH
Riboflavin: used to create flavin adenine dinucleotide
FAD states
FAD+, FADH, FADH2
Structure needed for acetyl CoA
Obvious; acetyl group. Attached to sulphur. Why? High energy bond.
Thioester role, how it does its role
Higher energy bond. The COOR is resonance stabilized, which would put it at a lower energy as it is more stable. COSR is less stable, can’t undergo resonance. Oxygen ester hydrolysis reaction:
COSR + H2O -> COOH + RSH
Thiamin B1 deficiency
Beriberi
Death, neuritis, heart failure, encephalopathy
Causes: excessive alcohol consumption, cooking
Riboflavin
Causes: no dairy products, light destruction
Symptoms: dermatitis, lesions of margin of lips, painful changes of tongue, dermatitis
Niacin deficiency
Pellagra Photosensitive skin rash Fatal if untreated Depressive psychosis Lethal
Can be synthesised by tryptophan by some extent
