Transcript Oxidative phosphorylation (mitochondria)

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 and
the PMF
Gut or lysozome
First, the entire process then I’ll break it
Cytosol
down into its parts.
Pyruvate
Aceyl CoA
Matrix
NADH, FADH2,
GTP
Stage 2
Oxidation, but not
Molecular O2
Some ATP but
inefficient.
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"
Interested? Check out “How we know”
"for his discovery of co-enzyme A and
its importance for intermediary
metabolism"
OVERVIEW….
Back to the mitochondrion…
~ same as cytosol
Impermeable, cristae,
Large surface, electron
transport
Porin, 5kDa exclusion
Overview of matrix and some inner membrane reactions.
Chemistry 11 refresher:
Reduced means received
An electron
Oxidized means
lost an electron
Negative means
good electron
donor pair
Oxygen readily
receives electrons
“things are oxidized
by oxygen”
~ energy of ADP +P
{
Positive voltage
means good
electron acceptor
Cyanide and CO block cytochrome c oxidase
Mitochondria DV is more important
Chloroplasts DpH is more important