Oxidation… not like burning a marshmallow. Rather, stepwise release of energy.

Oxidation… not like burning a marshmallow. Rather, stepwise release of energy.

Two primary forms of energy are:

Nucleotide triphosphate (e.g. ATP, GTP)Reducing power (NADH, NADPH)

Two ways to make them:

Through glycolysis (cytosol)Oxidative phosphorylation (mitochondria)

The driving force for oxidative phosphorylation is the movement of ions (from last two lectures)

Chemiosmotic coupling andthe PMF

Gut or lysozome

Cytosol

Matrix

Pyruvate

Aceyl CoA

NADH, FADH2, GTP

First, the entire process then I’ll break it down into its parts.

Stage 2

Oxidation, but not Molecular O2

Some ATP butinefficient.

Understand but don’t memorize 10 rxns, panel 13-1

What happens when molecular oxygen is absent?

If fermentation does not occur (i.e. oxygen is present), pyruvate is used for oxidative phosphorylation

… in the mitochondrion.

Let’s get oriented:

Pyruvate is rapidly taken up…. in the mitochondrial matrix:

In the matrix, FA are converted to acyl CoA

The Kreb Cycle reduced to its simplest form. This occurs w/ soluble enzymes in the matrix

Hans Adolf Krebs Fritz Albert Lipmann             

The Nobel Prize in Physiology or Medicine 1953

"for his discovery of the citric acid cycle"

"for his discovery of co-enzyme A and its importance for intermediary metabolism"

Interested? Check out “How we know”

OVERVIEW….

Back to the mitochondrion…

Porin, 5kDa exclusion

Impermeable, cristae,Large surface, electrontransport

~ same as cytosol

Overview of matrix and some inner membrane reactions.

Negative meansgood electrondonor pair

Positive voltagemeans good electron acceptor

Chemistry 11 refresher:Reduced means receivedAn electron

Oxidized means lost an electron

Oxygen readily receives electrons

“things are oxidizedby oxygen”

~ energy of ADP +P {

Cyanide and CO block cytochrome c oxidase

Mitochondria V is more importantChloroplasts pH is more important