After Glycolysis we have: 2 NADH, 4 ATP2 Pyruvate (3C)

Process was Anaerobic & took place in the cytoplasm of ALL cells

No O2 is required and the yield of ATP from a molecule of glucose is relatively small

What is the fate of pyruvate?

Fate of PyruvateIn order to keep glycolysis going the NADH formed must be

oxidized back to NAD+. This can be done Aerobically (with O2) or Anaerobically (without O2)

Anaerobic Breakdown of Pyruvate

Goal is to recycle NAD+/NADH

and keep Glycolysis running

The Mitochondrion

Double Membrane

Possesses its own DNA (mtDNA)

Inner Membrane is folded into CRISTAE

Space inside the Inner Membrane is known as the MATRIX

Site of AEROBIC RESPIRATION

Krebs or Citric Acid Cycle

Electron Transport Chain

The Krebs Cycle

Final Breakdown of Glucose

• Production of CO2

Series of REDOX Reactions

•LEO GER

Occurs in the Matrix

Transition Reaction

Oxidation of Pyruvate (3C -> 2C)– Pyruvate is Oxidized– NAD+ --> NADH

– CO2 removed (COO-) & Co-A added

STEP 1:

•Acetyl-CoA adds its 2C to Oxaloacetate (4C) producing Citrate (6C)

STEP 2:

•Citrate converted to IsoCitrate by the removal & addition of H2O

STEP 3: OXIDATION & De-Carboxylation

•Isocitrate is oxidized: NAD+ is reduced to NADH

•Carboxyl group -COO- is removed and exits as CO2

•6C --> 5C α-Ketoglutarate

STEP 4: OXIDATION & De-Carboxylation

∀α-Ketoglutarate is oxidized & NAD+ is reduced to NADH

•Again -COO- is removed as CO2

•Co-enzyme A is attached again

•5C --> 4C Succinyl-CoA

STEP 5:

•CoA is replaced by a PO4 group

•Succinyl-CoA (4C) --> Succinate (4C)

•PO4 group is then passed to GDP -> GTP

•GTP is then transformed into ATP

•In prokaryotes & plants ATP is made directly in this step

STEP 6: OXIDATION

•Succinate is oxidized & electrons are transferred to FAD+ to form FADH2

•FADH2 is similar to NADH and goes to the ETC

FAD+ = flavin adenine dinucleotide … comes from riboflavin (B-Vitamin)

•Succinate (4C) --> Fumarate (4C)

STEP 7:

•Addition of H2O to form 4C Malate

STEP 8: OXIDATION

•Malate is oxidized to form Oxaloacetate which can regenerate the Krebs Cycle

•NAD+ is reduced to NADH

Final Notes1. Book-Keeping

– For each pyruvate:• 4 NADH formed, 1 FADH2

• 1 ATP (as GTP)• Double this to get the total for 1 glucose molecule

1. Carbons– It takes 3 turns of the Krebs cycle for the 1st set of

C’s from acetyl-CoA to be removed

1. Where’s the Oxygen???