15. Adipose Tissue And Fatty Acid Synthesis Flashcards
General formula for fatty acids
H3C-CH2-COOH
How are fats stored?
In adipose tissue as triglycerides
Where does catabolism occur?
Cytoplasm
Where does anabolism occur?
Mitochondria
4 roles of fatty acids
Fuel
Covalent modification of proteins
Hormonal production
Glycerophosphate and sphingolipids
3 steps of aspirin overdose
1) Hyperventilation
2) Paradoxic aciduria
3) Dehydration
Explain each step of aspirin overdose
1) Direct respiratory centre stimulation - leads to respiratory alkalosis and compenstaroy alkuluria
2) H+ in urine, reuces sodium bicarbonate and potassium
3) Panting and vomiting, hypokalaemia and progressive metabolic acidosis
Why is aspirin toxic in high concentrations?
Prevents oxidative phosphorylation
Where are fatty acids synthesised from?
Acetyl CoA in the cytosol
Where is the fatty acid precursor formed?
Mitochondria
What molecule does the FA precursor bond with and what product does it form?
Oxaloacetate to form citrate
What enzyme catalyses isocitrate to a-KG? What inhibits this?
Isocitrate dehydrogenase
High ATP conc.
Explain how the accumulation of certain compounds leads to fatty acid synthesis
High ATP allosterically inhibits ICDH
IC accumulation leads to Citrate build up
This is forced into cytosol where FA synthesis takes place
What is the fate of citrate in terms of FA synthesis?
Cleaved by citrate lyase in cytosol
Forms OAA, then malate, then pyruvate again
CoA-SH of citrate lyase forms acetyl CoA
Explain the first committed step of FA synthesis
Acetyl CoA -> Malonyl CoA
Acetyl CoA carboxylased by AC Carboxylase (contains Biotin)
ATP is hydrolysed to fuel the process
