Download General Catabolic Pathway Glycolysis:

Oxidation, Reduction, and Energy
Cellular Respiration
Today s topics
Catabolic Oxidation of
Glucose
•  Glycolysis
–  Oxidation of glucose to
pyruvate
•  Mitochondria
–  Structure and function
•  It time: Citric Acid Cycle
–  Oxidation of pyruvate to
CO2
7 October 2016
1
Proteins Carbohydrates
General Catabolic Pathway
• 
Amino
acids
Sugars
Fats
Glycerol
Fatty
acids
Step down the oxidation series of carbon in a series of small Steps
Glycolysis
Some activation step
Glucose
Oxidation step, with energy harvest
Reorganization step
Another oxidation step, another harvest
Another reorganization
etc. etc.
Glyceraldehyde-3- P
NH3
Acetyl CoA
Citric
acid
cycle
yield product of pathway
3
Glycolysis:
6 carbon
sugar
Figure 9.19
Steps in the
oxidation of
glucose
Glucose
For each step:
What goes in?
What comes out?
Where does it
happen?
Harvest
ATP and NADH
oxidized to pyruvate
Pyruvate
Oxidative
phosphorylation
4
In Cytoplasm
In Mitochondrial
Matrix
Keep track of the
carbon atoms.
(Two)
3 carbon acids
5
Keep track of the
energy molecules.
On Inner
Mitochondrial
membrane
1
Glycolysis Summary
6-Carbon Sugar à 2x 3-Carbon Acids
Substrate-level
Phosphorylation
Energy harvest
phase
Energy investment
phase
8
7
H
Glycolysisthe details
HO
CH2OH
H
H
HO H
OH
OH
H
Glucose
ATP
1
Hexokinase
ADP
NAD+
is an electron
carrier
Energy
Investment
Stage
Add P to #6 carbon
CH2OH
P
O H
H
H
OH H
HO
H OH
Glucose-6-phosphate
Rearrange
2
Phosphoglucoisomerase
CH2O
P
O
CH2OH
H HO
HO
H
HO H
Fructose-6-phosphate
(see also NADP+ and FAD)
Split into two 3 carbon
units
Rearrange
Do Not Memorize!
3
ATP
Add P to #1 carbon
Phosphofructokinase
ADP
P O CH2 O CH2 O
HO
H
OH
HO H
Fructose1, 6-bisphosphate
4
Aldolase
P O CH2
C
5
H
Isomerase
O
CH2OH
Dihydroxyacetone
phosphate
Figure 9.9 A
Oxidize aldehyde to acid
add another phosphate
Harvest NADH
P
2 of
these
C O
CHOH
CH2 O
P
10
Glyceraldehyde3-phosphate
6
2 X Glyceraldehyde-3-P
Pi
NADH
Net Result of Glycolysis
+ 2 H+
2
P
O
C
O
CHOH
P
CH2
O
1, 3-Bisphosphoglycerate
Make ATP by
Substrate Level Phosphorylation
7
ATP
Glycolysis
Energy payoff
this pathway happens
twice for each glucose
O–
2
O
C
CHOH
O
CH2
3-Phosphoglycerate
–  # ATP:
P
8
Rearrange
O–
2
C
H
C
O
–  # eletron carriers:
P
O
CH2OH
2-Phosphoglycerate
9
Oxidize alcohol to ketone
Enolase
2 H2O
2
Make ATP by
Substrate Level Phosphorylation
O–
C
O
C
O
P
CH2
Phosphoenolpyruvate
10
ATP
Do Not Memorize!
2
Pyruvate x2
Figure 9.8 B
O–
C
O
C
O
11
12
CH3
2
Figure 9.6-3
What happens to the products of glycolysis?
Mitochondrion
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Matrix
Pyruvate
oxidation
Glycolysis
Glucose
Acetyl CoA
Pyruvate
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
Citric
acid
cycle
Inner
Membrane
MITOCHONDRION
CYTOSOL
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Proteins Carbohydrates
Amino
acids
Sugars
Outer
Membrane
ATP
ATP
Oxidative
phosphorylation
Intermembrane
Space
14
Fats
Glycerol
Pyruvate oxidation
Fatty
acids
Glycolysis
Glucose
Glyceraldehyde-3- P
NH3
Pyruvate
Acetyl CoA
Citric
acid
cycle
Oxidative
phosphorylation
15
Net Result of Citric Acid Cycle
and pyruvate oxidation
•  Pyruvate oxidation to acetyl-CoA
–  # ATP:
–  # electron carriers:
•  Citric acid cycle:
–  # ATP:
–  # electron carriers:
18
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