Aerobic Respiration

1
Aerobic Respiration
2
(No Transcript)
3
Pyruvate Oxidation /oxidative decarboxylation

• pyruvate (3-C) from glycolysis enters from the
  cytoplasm via a transport protein, consuming
  energy. It cannot diffuse because of its polarity
  
• pyruvate is oxidized into acetate (2-C), then
  converted into acetyl CoA
• provides link between glycolysis and the rest of
  cellular respiration
• involves pyruvate dehydrogenase a large enzyme
  complex that attached to the inner mitochondrial
  membrane
• pyruvate oxidation occurs in the mitochondrial
  matrix

4
(No Transcript)
5
Pyruvate Oxidation (contd)

• pyruvate dehydrogenase catalyzes 3 reactions in
  preparation for c.a.c.
• 1- pyruvate is oxidized to a 2-carbon acetyl
  group CO2 is released (oxidative
  decarboxylation)
• because CO2 is small and nonpolar, it can
  readily diffuse out of the mitochondria
• 2- NAD captures some energy from oxidation ?
  NADHH
• 3- Coenzyme A attaches to the acetyl group to
  form acetyl CoA
• Acetyl CoA enters the C.A.C. coenzyme A gets
  released so it can be used again in formation of
  acetyl CoA

6
Pyruvate dehydrogenase

• inhibitors have the overall effect of slowing
  this reaction when there is either little oxygen,
  or when the cell has a lot of energy

7
(No Transcript)
8
(No Transcript)
9
Citric Acid Cycle

• Acetyl CoA from pyruvate oxidation is the
  starting poing
• occurs in the mitochondrial matrix
• made up of 8 reactions
• energy in acetyl CoA drives the reaction of
  acetate (2-C) with oxaloacetate (4-C) to produce
  citrate (6-C).
• C.A.C.is a series of reactions in which citrate
  is oxidized and oxaloacetate regenerated (hence a
  "cycle")

10
Citric Acid Cycle

• Products for each turn of cycle (for each acetyl
  CoA)
• 2 CO2
• 1 FADH2
• 3 NADH
• 1 ATP for each acetyl CoA
• Double these numbers for one molecule of
  glucose!!

11
Accounting
12
(No Transcript)
13
Electron Transport Chain

• Electrons pass along a series of
  membrane-associated electron carriers
• FADH2 and NADH2 are relieved of their H and e-,
  replenishing the supply of FAD and NAD

14
e.t.c. contd

• Flow of reactions by way of redox reactions
  causes the active transport of protons across the
  inner mit. Membrane into the intermembrane
  space ? proton gradient
• Protons diffuse through proton channels down the
  concentration gradient electrical gradient back
  into the matrix of the mitochondria, making ATP
  in the process
• oxidative phosphorylation ATP synthesis by
  e.t.c.