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Pg. 79 Glycolysis
 An overview of cellular respiration
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Glycolsis
Pyruvate
Glucose
Cytosol
ATP
Figure 9.6
Substrate-level
phosphorylation
Citric
acid
cycle
Oxidative
phosphorylation:
electron
transport and
chemiosmosis
Mitochondrion
ATP
Substrate-level
phosphorylation
ATP
Oxidative
phosphorylation
 Key Point #1: Glycolysis:
 Splitting 0f sugar
 Location?
 The cytoplasm of the cell (plants and animal cells)
Glycolysis
ATP
 Key Point #2: Glycolysis consists of
two major phases
 Energy investment phase
 Energy payoff phase
Citric
acid
cycle
Oxidative
phosphorylation
ATP
ATP
Energy investment phase
Glucose
2 ATP + 2 P
used
2 ATP
Energy payoff phase
 Key Point #3: Glycolysis begins with
glucose
4 ADP + 4
P
2 NAD+ + 4 e- + 4 H +
4 ATP
formed
2 NADH
+ 2 H+
2 Pyruvate + 2 H2O
Glucose
4 ATP formed – 2 ATP used
Figure 9.8
2 NAD+ + 4 e– + 4 H +
2 Pyruvate + 2 H2O
2 ATP
+ 2 H+
2 NADH
A closer look at the energy investment
phase
 Investment?
CH2OH
H
H
HO H
HO
OH
H OH
H
Glycolysis
Citric
acid
cycle
Oxidative
phosphorylation
Glucose
ATP
1
Hexokinase
ADP
CH2OH
P
O H
H
H H
OH
HO
H OH
Glucose-6-phosphate
2
Phosphoglucoisomerase
CH2O
P
O
CH2OH
H HO
HO
H
HO H
Fructose-6-phosphate
3
ATP
Phosphofructokinase
ADP
P O CH2 O CH2 O
HO
H
OH
HO H
Fructose1, 6-bisphosphate
P
4
Aldolase
5
P
O CH2 Isomerase
C O
CH2OH
Dihydroxyacetone
phosphate
Figure 9.9 A
H
C O
CHOH
CH2 O P
Glyceraldehyde3-phosphate
2 ATP molecules are
invested.
Need money to
make money!
A closer look at the energy payoff
phase
 Payoff?
6
Triose phosphate
dehydrogenase
2 NAD+
2
2 Pi
NADH
+ 2 H+
2
P
O
C
O
CHOH
CH2 O P
1, 3-Bisphosphoglycerate
2 ADP
7
Phosphoglycerokinase
2 ATP
O–
2
C
CHOH
CH2 O P
3-Phosphoglycerate
8
Phosphoglyceromutase
O–
2
C
H
C
O
P
O
CH2OH
2-Phosphoglycerate
9
Enolase
2 H2 O
2
O–
C
O
C
O
P
CH2
Phosphoenolpyruvate
2 ADP
10
Pyruvate kinase
2 ATP
2
Figure 9.8 B
O–
C
O
C
O
CH3
Pyruvate
4 ATP molecules are
produced.
4- 2(energy
investment phase)=
2 ATP left!
 Key Point #4: Glycolysis ends with 2 pyruvate
molecules
6
Triose phosphate
dehydrogenase
2 NAD+
2
2 Pi
NADH
+ 2 H+
2
P
O
C
O
CHOH
CH2 O P
1, 3-Bisphosphoglycerate
2 ADP
7
Phosphoglycerokinase
2 ATP
O–
2
C
CHOH
CH2 O P
3-Phosphoglycerate
8
Phosphoglyceromutase
O–
2
C
H
C
O
P
O
CH2OH
2-Phosphoglycerate
9
Enolase
2 H2 O
2
O–
C
O
C
O
P
CH2
Phosphoenolpyruvate
2 ADP
10
Pyruvate kinase
2 ATP
2
Figure 9.8 B
O–
C
O
C
O
CH3
Pyruvate
End products
 Key Point #5: Glycolysis summary:
 Begin with 1 glucose  end with 2 ATP’s, 2 pyruvates,
and 2 NADH’s
 Next, pyruvates head straight to the mitochondria!
 How are the ATP’s made?
Substrate-level phosphorylation
 Key Point #6: Substrate-level phosphorylation:
 Enzymes transfer a phosphate group from a substrate to ADP ATP
 Occurs in glycolysis and the citric acid cycle
Enzyme
Enzyme
ADP
P
Substrate
+
Figure 9.7
Product
ATP
 Timed ten
 12:55-1:05
 Class wrap-up:
 1:05-1:09