Metabolism and ATP synthesis
I
Metabolism: Is the sum of all chemical reactions in the body.
A
metabolism is divided into two types of classes: catabolism and anabolism.
1.
Catabolism
2.
Anabolism
3.
What do catabolic reactions do?
4
Where is the energy stored?
a.
II
How is energy transferred from large compounds to make ATP.
A
Energy is often transferred from one molecule to another by oxidation reduction
reactions.
1.
Energy is transferred when electrons from a molecule being oxidized are
shifted to a molecule being reduced.
a.
Oxidation is the ________ of electrons
b.
Reduction is the ________ o f electrons
c.
How do oxidation and reduction occur?
d.
Why do most microorganisms oxidize carbohydrates?
B
Oxygen dependent Microorganisms use a series of oxidation reduction reactions
called cellular respiration to produce energy from glucose.
1.
Cellular respiration oxidizes glucose to reduce NAD+ to NADH.
a.
NADH is an electron carrier
2.
Cellular respiration has three stages, glycolysis, krebs and electron
transport.
a.
Glycolysis is the oxidation of glucose to Pyruvic acid to produce 2
ATP and 2 NADH.
1.
Occurs in the cytoplasm of both procaryotes and eucaryotes
2.
Preparatory step: two pyruvic acid molecules converted into
two acetyl CO-A, yielding two NADH.
b.
Krebs cycle is the oxidation of acetyl co- A to carbon dioxide to
produce one molecule of ATP, three NADH and 1 FADH per
acetyl Co-A
1.
Occurs in the cytoplasm procaryotes but in the mitochondria
in eucaryotes
c.
Electron transport converts the energy in NADH and FADH
molecules into a hydrogen gradient in the mitochondria.
1.
Occurs in the plasma membrane of prokaryotes and in the
inner mitochondrial membrane in eucaryotes.
2.
The hydrogen gradient built up in t he mitochondria is
responsible for the production of most of the ATP in the
cell.
3.
H+ ions pass through ATP synthase stimulating it to
produce ATP from ADP.
D
III
ATP yield from procaryotic respiration
1.
Each NADH produces eno ugh H+ to account for the production of 3
ATPs. Each FADH is worth 2 ATPs
a
glycolysis = 8 ATP (6 from 2 NADH and 2 produced during
glycolysis)
b.
Preparatory Step in which pyruvic acid is converted into Acetyl CoA = 6 ATP (from 2 NADH)
c.
Krebs cycle = 18 ATP (from 6 NADH) + 4 ATP (from 2 FADH) +
2 ATP produced in the cycle.
d.
Total = 38 ATP in procaryotes
e.
In eukaryotes it cost the cell 2 ATP to get the 2 molecules of
NADH produced in glycolysis into the mitochondria.
Fermentation. Organisms produce ATP in the absence of oxygen.
A.
Fermentation produces ATP through glycolysis.
1.
Fermentation does not use the krebs cycle or the electron transport.
2.
NADH is used to reduce pyruvic acid to either lactic acid or alcohol.
a.
NADH is converted back to NAD+