Aerobic respiration - the TCA cycle Flashcards
Outline the reaction pyruvate into acetyl Co.
Pyruvate + CoA +NAD+ > Acetyl CoA + CO2 + NADH + H+
Which enzyme converts pruvate to acetyl CoA?
Pyruvate dehydrogenase
List the 10 products in order in the TCA cycle
Pyruvate Acetyl CoA Citrate Isocitrate alpha-ketoglutarate Succinyl-CoA Succinate Fumarate Malate Oxaloacetate
What reaction initiates the TCA cycle and the enzyme that catalyses it?
Oxaloacetate + Acetyl CoA
Catalysed by Citrate synthase
Produces Citrate and regenerates CoA
What enzyme catalyses the reaction of citrate into isocitrate?
Aconitase
Describe the reaction of isocitrate into a-ketoglutarate.
Enzyme, product, co-factors
Enzyme: Isocitrate dehydrogenase
Releases CO2
Reduces NAD+ > NADH + H+
Oxidation reaction
Describe the reaction of a-ketoglutarate to succinyl-CoA.
Enzyme, products, co-factors.
Enzyme: ketoglutarate dehydrogenase
Releases CO2
Co-factor: NAD+ is reduced to NADH
Describe the reaction of succinyl-CoA to succinate.
Enzyme: succinate thiokinase
Release CoA
Substrate level phosphorylation of GDP+Pi>GTP.
Describe the reaction of succinate into fumarate.
Enzyme: Succinate dehydrogenase
Co-Factor: FAD > FADH2
Dehydrogenation reaction
Describe the reaction of fumarate into malate.
Enzyme: Fumarase
Hydration reaction - addition of H2O
Describe the reaction of malate to oxaloacetate.
Enzyme: malate dehydrogenase
Reduction of NAD+ > NADH
Outline the reaction of FAD as an H+ acceptor.
FAD + 2H+ + 2e- > FADH2
FAD = flavin adenine dinucleotide
Describe 3 other biosynthetic roles of oxaloacetate.
Carboxylation of oxaloacetate into phosphoenol-pyruvate by PEP carboxylase.
Transamination of oxaloacetate into aspartate - used to form other purines, pyrimidines and amino acids.
Direct carboxylation of oxaloacetate into pyruvate using pyruvate carboxylase.
How many molecules of ATP does one molecule of NADH generate?
3 molecules in the electron transfer chain - releases energy for ATP-synthase
How many molecules of ATP does one molecule of FADH2 generate?
2 molecules of ATP
