2/8/2012
Cellular Respiration
Chapter 5 Outline
Glycolysis
Occurs in a series of reactions:
1. Glycolysis
2. Citric acid cycle (aka TCA or Kreb’s Cycle)
3. Electron transport system
Aerobic
Respiration
Lactic Acid Pathway
Glycogenesis, glycogenolysis, gluconeogenesis
2
5-2
General to the Specific
Break down of large
Molecules to simple
molecules
Break down simple
molecules to Acetyl
CoA
Oxidation of Acyetl
CoA to H20 and
CO2 – produce Eand make ATP
5-4
Carbohydrate Catabolism
Glycolysis
(ATP generated by ETC)
(ATP generated by breaking
bonds)
Figure 24.5
5-5
1
2/8/2012
Glycolysis (General)
In
glycolysis 2 ATPs are added and 4 are produced for
a net gain of 2 ATP
Glycolysis (Specific)
Event 1 Phosphorylation
• Two phosphates
added to glucose
• Requires ATP
Glucose
Phase 1
priming
Carbon atom
P Phosphate
2 ATP
2 ADP
Fructose-1,6-diphosphate
P
P
Phase 2
cleavage
Event 2 – Splitting
(cleavage)
• 6-carbon glucose
split into two 3-carbon
molecules
Dihydroxyacetone
phosphate
Glyceraldehyde
phosphate
P
Phase 3
oxidation and
formation of
ATP and release
of high energy
electrons
Glyceraldehyde
phosphate
P
P
1 NAD+
2 ADP
1 NADH + H+
2 ATP
1 Pyruvic acid
1 Pyruvic acid
O2
O22
O
2 NADH + H+
2 NAD+
To citric acid cycle
and electron transport
chain (aerobic pathway)
2 Lactic acid
8
5-8
Glycolysis
Glycolysis
Event 3 – Production of
NADH and ATP
• H atoms released
• Bind to NAD+ to produce
NADH
• NADH delivers H+ to ETC
• ADP is phosphorylated to
ATP
• 2 pyruvic acid are produced
• 2 ATP are generated
(4 – 2 [used to start] = 2)
Glucose
Phase 1
priming
Carbon atom
P Phosphate
2 ATP
2 ADP
Fructose-1,6-diphosphate
P
P
Phase 2
cleavage
Dihydroxyacetone
phosphate
Glyceraldehyde
phosphate
P
Phase 3
oxidation and
formation of
ATP and release
of high energy
electrons
Glyceraldehyde
phosphate
P
P
2 ADP
1 NAD+
1 NADH + H+
2 ATP
1 Pyruvic acid
1 Pyruvic acid
O2
O22
O
2 NADH + H+
2 NAD+
To citric acid cycle
and electron transport
chain (aerobic pathway)
2 Lactic acid
9
5-9
Aerobic Respiration
5-16
2
2/8/2012
Carbohydrate Catabolism
Krebs Cycle (General)
 In
mitochondria matrix
 Begins
with acetyl CoA
combining with
oxaloacetic acid to form
citric acid
 In
a series of reactions
citric acid converted back
to oxaloacetic acid to
complete the pathway
Figure 24.5
5-18
Mitochondrial Matrix Reactions (Specific)
6
Cytosol
Pyruvic acid from glycolysis
Glycolysis
Krebs
cycle
Pyruvic acid (C3)
Electron
transport chain
and oxidative
phosphorylation
CoA
Acetyl CoA
CO2
ATP
ATP
NAD+
CO2
NADH+H+
Mitochondrion
(fluid matrix)
ATP
NAD+
7
NADH + H+
Acetyl group (C2)
8
Acetyl-Co A
Coenzyme A
H2O
9
Citric acid (C6)
Oxaloacetic acid (C4)
H2O
10
NADH + H+
18
NAD+
(C6)
Citric
acid
cycle
NAD+
H2O
11
NADH + H+
(C4)
12
CO2
17
(C5)
H2O
NAD+
13
Occurs in
mitochondrial
matrix
(C4)
Key:
NADH + H+
= Carbon atom
14
16
FADH2
(C4)
CO2
FAD
Pi = Inorganic phosphate
(C4)
Pi
CoA = Coenzyme A
15
GTP
GDP
26-15
ADP
Figure 24.7
ATP
Pyruvic acid from glycolysis
Glycolysis
ATP
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
ATP
Cytosol
CoA
Acetyl CoA
NADH+H+
(pickup molecule)
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
Mitochondrion
(fluid matrix)
ATP
ATP
Oxaloacetic acid
Cytosol
Pyruvic acid from glycolysis
Glycolysis
NAD+
CO2
ATP
NAD+
CO2
CoA
Acetyl CoA
Oxaloacetic acid
Citric acid
(pickup molecule)
CoA (initial reactant)
NADH+H+
Mitochondrion
(fluid matrix)
ATP
Citric acid
CoA (initial reactant)
Isocitric acid
Krebs cycle
Krebs cycle
Key:
Key:
= Carbon atom
= Carbon atom
Pi = Inorganic phosphate
Pi = Inorganic phosphate
CoA = Coenzyme A
CoA = Coenzyme A
Figure 24.7
Figure 24.7
3
2/8/2012
Cytosol
Pyruvic acid from glycolysis
Glycolysis
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
CoA
Acetyl CoA
ATP
ATP
(pickup molecule)
Electron
transport chain
and oxidative
phosphorylation
NAD+
CO2
CoA
Acetyl CoA
ATP
ATP
ATP
Oxaloacetic acid
Krebs
cycle
Mitochondrion
(fluid matrix)
NADH+H+
Cytosol
Pyruvic acid from glycolysis
Glycolysis
NAD+
CO2
Mitochondrion
(fluid matrix)
NADH+H+
ATP
Oxaloacetic acid
Citric acid
(pickup molecule)
CoA (initial reactant)
Citric acid
CoA (initial reactant)
Isocitric acid
Isocitric acid
NAD+
Krebs cycle
NAD+
Krebs cycle
CO2
CO2
NADH+H+
NADH+H+
a-Ketoglutaric acid
a-Ketoglutaric acid
CoA
NAD+
CO2
Succinyl-CoA
Key:
NADH+H+
Key:
= Carbon atom
= Carbon atom
Pi = Inorganic phosphate
Pi = Inorganic phosphate
CoA = Coenzyme A
CoA = Coenzyme A
Figure 24.7
Cytosol
Pyruvic acid from glycolysis
Glycolysis
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
(pickup molecule)
Electron
transport chain
and oxidative
phosphorylation
NAD+
CO2
CoA
Acetyl CoA
ATP
ATP
ATP
Oxaloacetic acid
Krebs
cycle
Mitochondrion
(fluid matrix)
NADH+H+
Cytosol
Pyruvic acid from glycolysis
Glycolysis
NAD+
CO2
CoA
Acetyl CoA
ATP
ATP
Figure 24.7
Mitochondrion
(fluid matrix)
NADH+H+
ATP
Oxaloacetic acid
Citric acid
(pickup molecule)
CoA (initial reactant)
Citric acid
CoA (initial reactant)
Isocitric acid
Isocitric acid
NAD+
Krebs cycle
NAD+
Krebs cycle
CO2
CO2
NADH+H+
NADH+H+
a-Ketoglutaric acid
CoA
NAD+
CO2
Succinic acid
Key:
Succinyl-CoA
Succinic acid
FAD
Key:
GTP
GDP + Pi
Succinyl-CoA
NADH+H+
CoA
= Carbon atom
Pi = Inorganic phosphate
CoA
NAD+
CO2
FADH2
NADH+H+
CoA
= Carbon atom
a-Ketoglutaric acid
Fumaric acid
GTP
GDP + Pi
ADP
ATP
Pi = Inorganic phosphate
CoA = Coenzyme A
CoA = Coenzyme A
ATP
ADP
Figure 24.7
Cytosol
Pyruvic acid from glycolysis
Glycolysis
ATP
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
ATP
ATP
Oxaloacetic acid
(pickup molecule)
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
NAD+
CO2
Mitochondrion
(fluid matrix)
NADH+H+
Cytosol
Pyruvic acid from glycolysis
Glycolysis
NAD+
CO2
CoA
Acetyl CoA
ATP
Figure 24.7
CoA
Acetyl CoA
ATP
Oxaloacetic acid
Citric acid
(pickup molecule)
NADH+H+
CoA (initial reactant)
Mitochondrion
(fluid matrix)
NADH+H+
ATP
Citric acid
CoA (initial reactant)
NAD+
Isocitric acid
Malic acid
Isocitric acid
Malic acid
NAD+
Krebs cycle
NAD+
Krebs cycle
CO2
CO2
NADH+H+
CO2
FADH2
FAD
Key:
NADH+H+
a-Ketoglutaric acid
Fumaric acid
Succinic acid
Succinyl-CoA
CoA
NAD+
FAD
Key:
GTP
GDP + Pi
Succinic acid
Succinyl-CoA
CoA
NAD+
NADH+H+
CoA
= Carbon atom
Pi = Inorganic phosphate
CoA = Coenzyme A
CO2
FADH2
NADH+H+
CoA
= Carbon atom
a-Ketoglutaric acid
Fumaric acid
GTP
GDP + Pi
ADP
ATP
Pi = Inorganic phosphate
ADP
CoA = Coenzyme A
ATP
Figure 24.7
Figure 24.7
4
2/8/2012
Krebs Cycle
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5-20
Summary of Matrix Reactions
Electron Transport Chain
2 pyruvate + 6 H2O  6 CO2
2 ADP + 2 Pi  2 ATP
6 NAD+ + 6 H2  6 NADH + 6 H+
of glucose have all been carried away as CO 2
 Also,
citric acid cycle is a source of substances for synthesis
of fats and nonessential amino acids (later)
Relative free energy (kcal/mole)
Fe-S
2 FAD + 2 H2  2 FADH2
and exhaled
NAD+
FMN
(+2 NADH produced during glycolysis)
 carbon atoms
NADH + H+
50
40
FADH2
FAD
Enzyme complex 1
CoQ
30
Cyt b
Fe-S
Cyt c1
1
20
Enzyme complex 2
Cyt c
Cu
10
Cyt a
Cyt a3
Enzyme complex 3
0
26-28
26-27
•
ADP + P
ATP synthase
H2O
Reaction progress
Electron Transport and Oxidative
Phosphorylation
Electron Transport System
NADH and FADH2 carry electrons to the ETS
• ETS is a series of electron carriers (proteins) (in
cristae of mitochondria)
• Energy from electrons transferred to ATP synthase
• ATP synthase catalyzes the phosphorylation of ADP to
ATP
• Water is formed
½ O2 + 2 H+
The
electron transport chain is a linked series of
proteins on the cristae of mitochondria
Proteins are FMN, coenzyme Q, and cytochromes
ATP
Energy
NADH + H+
Energy
2H+ + 2e–
NAD+
Energy
FADH2
2H+ + 2e–
FAD
Electron transport chain
2e–
2H+
O2
H2O
29
5-21
5
2/8/2012
Glycolysis
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
ATP
ATP
ATP
Glycolysis
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
ATP
ATP
ATP
H+
H+
H+
Core
Intermembrane
space
Core
Intermembrane
space
Cyt c
Cyt c
e-
Q
1
Q
1
3
3
2
2
Inner
mitochondrial
membrane
Inner
mitochondrial
membrane
NADH + H+
Mitochondrial
matrix
FADH2
NADH + H+
NAD +
e-
Mitochondrial
matrix
Electron Transport Chain
FAD
NAD +
(carrying e from food)
Electron Transport Chain
Figure 24.8
Glycolysis
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
ATP
ATP
ATP
H+
H+
Figure 24.8
Glycolysis
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
ATP
ATP
ATP
Intermembrane
space
Cyt c
e-
eQ
1
H+
H+
Core
Intermembrane
space
FADH2
NADH + H+
Mitochondrial
matrix
e-
eQ
1
3
3
2
Inner
mitochondrial
membrane
FAD
FADH2
NADH + H+
NAD +
(carrying e from food)
FAD
NAD +
(carrying e from food)
Mitochondrial
matrix
Electron Transport Chain
Electron Transport Chain
ATP Synthase
Figure 24.8
Glycolysis
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
ATP
ATP
ATP
H+
H+
Intermembrane
space
Q
Glycolysis
Krebs
cycle
Electron
transport chain
and oxidative
phosphorylation
ATP
ATP
ATP
H+
Intermembrane
space
e-
FADH2
NADH + H+
(carrying e from food)
Mitochondrial
matrix
Q
1
3
2
Inner
mitochondrial
membrane
FAD
ATP
ADP + Pi
ATP Synthase
Figure 24.8
2 H+ +
FADH2
NADH + H+
(carrying e from food)
H+
Electron Transport Chain
e-
e-
3
NAD +
Core
Cyt c
2
Inner
mitochondrial
membrane
H+
H+
Core
Cyt c
e-
Figure 24.8
H+
H+
H+
1
Core
Cyt c
2
Inner
mitochondrial
membrane
H+
H+
H+
Mitochondrial
matrix
1
2
O2
H2O
FAD
ATP
ADP + Pi
NAD +
H+
Electron Transport Chain
ATP Synthase
Figure 24.8
6
2/8/2012
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operating systems, some animations
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ETC
Chemiosmotic ATP Synthesis
Intermembrane
space
Matrix
Cristae
Inner membrane
Outer membrane
½ O2 + 2 H+
NADH + H+ NAD+
6 H+
H2O
Matrix
2e–
Inner
membrane
Enzyme
complex
1
CoQ
2e–
2e–
Enzyme
complex
2
Enzyme
complex
3
3 ADP + 3 Pi
3 ATP
ATP
synthase
Cyt c
Intermembrane
space
2 H+
2 H+
2 H+
Outer
membrane
5-24
ATP Generated by Oxidation of Glucose
26-40
Anaerobic Reactions
Glucose
2
Glycolysis
ATP
(net)
2 NADH + 2 H+
Cytosol
2 pyruvate
• If oxygen is not available:
• ETC cannot accept
electrons from NADH
•Pyruvic acid is converted
to lactic acid
• Glycolysis is inhibited
• Less ATP produced
CO2
6 NADH + 6 H+
Citric acid
cycle
2 ATP
Electron-transport
chain
O2
Carbon atom
P Phosphate
2 ATP
2 ADP
Fructose-1,6-diphosphate
P
P
Dihydroxyacetone
Glyceraldehyde
phosphate
phosphate
P
P
Phase 3
P
oxidation and
1 NAD+
formation of
2 ADP
ATP and release
1 NADH + H+
of high energy
2 ATP
electrons
Pyruvic acid
O2
2 FADH2
26-41
Glucose
Phase 2
cleavage
Mitochondria
2 NADH + 2 H+
Phase 1
priming
H2O
4 ATP
28–30
ATP
Total 36–38
ATP
O2
2 NADH + H+
2 NAD+
2 Lactic acid
To citric acid cycle
and electron transport
chain (aerobic pathway)
42
7
2/8/2012
Lactic Acid Pathway
Lactic Acid Pathway
In
absence of O2 - - NADH + H gives its Hs to
pyruvic acid creating lactic acid
Anaerobic metabolism or Lactic acid fermentation)
Only
yields a net gain of 2 ATPs per glucose
don’t have mitochondria; use only lactic acid
pathway
Occurs in skeletal and heart muscle when oxygen
supply falls below critical level
During heavy exercise or vascular blockage
RBCs
5-10
5-11
Glycogenesis and Glycogenolysis
Break down of large
Molecules to simple
molecules
For
osmotic reasons cells can’t store lots of free
glucoses in cells – we change it to glycogen
Glycogen = polymers of glucose
Glucose to Glycogen = (Glycogenesis)
Place a P group on glucose and take it back off
Polymerizes glucose to glycogen
Skeletal muscle & liver store glycogen
Glycogenolysis = glycogen to glucose
Add the P back to Glucose (glucose 6 phosphate)
Most cells can use for glycolysis
If P attached to Glucose – it can’t leave cell
Break down simple
molecules to Acetyl
CoA
Oxidation of Acyetl
CoA to H20 and
CO2 – produce Eand make ATP
5-12
Cori Cycle
Glycogenesis and Glycogenolysis


Skeletal muscles use
trapped glucose-6phosphate for own energy
needs
- i.e., uses it for glycolysis
- cannot release into
blood
glycogenisis
Some skeletal muscle lactic acid goes to liver
 Gluconeogenesis: convert non-carb molecules (e.g. lactic acid)
back through pyruvic acid to glucose and glycogen
Glycogenolysis
(Glycogen
synthase)
(glycogen
phosphorylase)
Glucose-6
phosphotase

Only liver has glucose-6phosphatase that removes
phosphate groups
 So it can secrete free
glucose into blood
Rule to remember - - Org. molecules
w/ phosphate groups can not pass
through plasma membrane
(Lactic acid
dehydrogenase)
5-14
5-15
8