BIOL2171 Lecture Notes - Lecture 12: Mitochondrial Matrix, Citric Acid Cycle, Atp Synthase
Making ATP: Oxidative Phosphorylation
• Highly efficient
• The culmination of catabolic metabolism
• Generation of high amounts of ATP
•
• Mitochondrial process
o Converts potential energy into real energy
o Two membrane system
• Outer membrane like a sieve: big pores
• Inner membrane: very tightly regulated
▪ Very densely backed lipid membrane
• Must transport the energy too
o Synthesis of ATP requires:
• High energy intermediates
• Transport of intermediates into the mitochondrial matrix
• Electron transport chain
• ATP synthase
• Translocase to deliver ATP to cytosol
o Metabolic funnelling to mitochondria
• Two big systems: fats and carbohydrates
• FAs enter the mitochondria via the carnitine shuttle system
• β-oxidation occurs in matrix – produces acetyl-CoA
• Carbohydrates provide pyruvate (cytosol)
• Transported into matrix - metabolised to acetyl-CoA
• Destination for catabolic oxidation is the TCA cycle
• Entry to the TCA cycle is via acetyl-CoA
• TCA "energy products" are NADH and FADH2
▪ Catabolic reactions have involved oxidative processes
• Burnt sugars: converted into carbon dioxide
• Energy within bonds: electrons have a lot of energy associated with
them
▪ Oxidation = loss of electrons
▪ Reduction = addition of electrons
• Transfer electrons to high affinity molecules
• Most energy transductions involve flow of electrons between molecules
• Flow is in a "downward" direction - ie. To molecules with greater affinity for the
electrons
• Have not lost energy, just taken from the carbon source
• How electrons mov: these take and hold electrons
▪ Incorporated into a variety of biological molecules
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