The roles of ATP in living cells and mechanisms of production part 2 Flashcards
what is the role of pyruvate in metabolism
lactate (lactate dehydrogenase)
oxaloacetate (pyruvate carboxylase)
Acetyl-CoA (pyruvate dehydrogenase complex)
Alanine (alanine aminotransferases)
what happens to pyruvate under aerobic conditions
Under aerobic conditions, conversion to acetyl-CoA for oxidation and complete degradation
Occurs in mitochondria
Inner mitochondrial membrane highly selectively permeable
where does glycolysis occur
Glycolysis occurs in cytosol (can proceed in presence and absence of O2) – pyruvate transported into mitochondria for complete oxidation
how is pyruvate transported into the mitochondria
Occurs via specific carrier protein embedded in mitochondrial membrane in aerobic conditions
how is pyruvate converted to Acetyl-CoA
Pyruvate undergoes oxidative decarboxylation by pyruvate dehydrogenase complex to form Acetyl-CoA
pyruvate+CoA+NAD+>Acetyl-CoA+CO2+NADH+H+
Reaction is irreversible and link between glycolysis and citric acid cycle
Catalysed by PDH complex – 3 enzymes and 5 coenzymes
What is the tricarboxylate acid cycle
Aka citric acid or krebs cycle
Final common pathway for oxidation of fuel molecules
Acetyl residues (CH3-CO-) are oxidised to co2
Reducing equivalents transferred to NAD+ or FAD to form NADH and FADH2
what is an overview of the TCA cycle
4CU condenses with 2CU
Eventually 2 carbons leave cycle as CO2 and the 4CU regenerated
C2
C6-(NADH CO2)-C5-(NADH CO2)-C4-(GTP FADH2 NADH)-C4-START
Involves 4 oxidation-reduction reactions (NADH and FADH2 production) and one ATP is produced for each round
What are the 8 intermediates in the TCA cycle
acetyl-coa citrate isocitrate a-ketoglutarate succinyl-CoA succinate fumarate L-malate oxaloacetate After class I keep some specific factors more or-less A certificate in karma sutra should further my orgasm
what are the important enzymes of the TCA cycle
citrate synthase - condensation
isocitrate dehydrogenase and a-ketoglutarate dehydrogenase - oxidative decarboxylation
how is the TCA cycle regulated
Flow of carbon atoms from pyruvate into and through the TCA cycle is tightly regulated at 2 levels
1 conversion of pyruvate to acetyl-CoA (PDH reaction)
2 entry of acetyl-CoA into TCA cycle (citrate synthase reaction)
Also regulated at isocitrate dehydrogenase and a-ketoglutarate dehydrogenase reactionsIrreversible reactions are main regulatory points
what alters the TCA cycle
High ATP, acetyl-CoA, NADH, fatty acids inhibit cycle
High AMP, CoA, NAD+, Ca2+ increase rate of cycle
what other compounds feed into the TCA cycle
Fatty acids and some amino acids can be a source of Acetyl-CoA
how are the components of the TCA cycle important
important biosynthetic intermediates
Replenished by anaplerotic reactions
Conc of TCA intermediates in dynamic balance
what are the products of the TCA cycle
Products of TCA cycle 3 NADH, 1 FADH2, 1 GTP (ATP) 2 CO2 also Glucose – 2 pyruvate – 2 acetyl-CoA glycolysis -pyruvate and NADH NADH and FADH2 oxidised by mitochondrial ETC
What is the issue of NADH and the mitochondrial membrane
Inner mitochondrial membrane impermeable to NADH and no carrier in membrane
Electrons from NADH enter
2 shuttles
The glycerol-3-phosphate – esp in brain and muscles
The malate-aspartate – in liver and heart
Act to regenerate NAD+ to make 1.5 to 2.5 moles of ATP
