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Chp 9: Cellular Respiration
Figure 9-01
LE 9-2
Light
energy
ECOSYSTEM
Photosynthesis
in chloroplasts
Organic + O
molecules 2
CO2 + H2O
Cellular respiration
in mitochondria
ATP
powers most cellular work
Heat
energy
LE 9-6_3
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Glycolysis
Pyruvate
Glucose
Cytosol
Citric
acid
cycle
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
Mitochondrion
ATP
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Oxidative
phosphorylation
Activity: Overview
LE 9-7
Enzyme
Enzyme
ADP
P
Substrate
+
Product
ATP
LE 9-UN161a
becomes oxidized
(loses electron)
becomes reduced
(gains electron)
LE 9-UN161
becomes oxidized
becomes reduced
LE 9-3
Products
Reactants
becomes oxidized
CH4
2 O2
+
CO2
C
Energy
2 H2O
+
becomes reduced
H
H
+
H
O
O
O
C
O
H
O
H
Methane
(reducing
agent)
Oxygen
(oxidizing
agent)
Carbon dioxide
Water
H
LE 9-UN162a
becomes oxidized
becomes reduced
LE 9-UN162b
Dehydrogenase
LE 9-4
2 e– + 2 H+
NAD+
2 e– + H+
H+
NADH
Dehydrogenase
+ 2[H]
(from food)
Nicotinamide
(oxidized form)
+
Nicotinamide
(reduced form)
H+
LE 9-5
H2 + 1/2 O2
+
2H
1 /2
O2
1/2
O2
(from food via NADH)
Explosive
release of
heat and light
energy
Free energy, G
Free energy, G
2 H+ + 2 e–
Controlled
release of
energy for
synthesis of
ATP
ATP
ATP
ATP
2 e–
2
H+
H2O
Uncontrolled reaction
H2O
Cellular respiration
LE 9-UN164
1. Glycolysis (color-coded teal throughout the chapter)
2. The citric acid cycle (color-coded salmon)
3. Oxidation phosphorylation: electron transport and
chemiosmosis (color-coded violet)
LE 9-6_3
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Glycolysis
Pyruvate
Glucose
Cytosol
Citric
acid
cycle
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
Mitochondrion
ATP
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Oxidative
phosphorylation
LE 9-8
Energy investment phase
Glucose
2 ATP used
2 ADP + 2 P
Glycolysis
Citric
acid
cycle
Oxidative
phosphorylation
Energy payoff phase
ATP
ATP
ATP
4 ADP + 4 P
2 NAD+ + 4 e– + 4 H+
4 ATP formed
2 NADH + 2 H+
2 Pyruvate + 2 H2O
Net
Glucose
4 ATP formed – 2 ATP used
2 NAD+ + 4 e– + 4 H+
Activity: Glycolysis
2 Pyruvate + 2 H2O
2 ATP
2 NADH + 2 H+
LE 9-10
MITOCHONDRION
CYTOSOL
NAD+
NADH
+ H+
Acetyl Co A
Pyruvate
Transport protein
CO2
Coenzyme A
LE 9-12_4
Glycolysis
Citric
acid
cycle
ATP
ATP
Oxidation
phosphorylation
ATP
Acetyl CoA
NADH
+ H+
H2O
NAD+
Oxaloacetate
Malate
Citrate
Isocitrate
CO2
Citric
acid
cycle
H2O
NAD+
NADH
+ H+
Fumarate
a-Ketoglutarate
FADH2
NAD+
FAD
Succinate
GTP GDP
Pi
Succinyl
CoA
CO2
NADH
+ H+
ADP
ATP
Activity: Citric Acid
Cycle (Krebs Cycle)
LE 9-11
Pyruvate
(from glycolysis,
2 molecules per glucose)
CO2
NAD+
Glycolysis
Citric
acid
cycle
ATP
ATP
Oxidation
phosphorylation
CoA
NADH
+ H+
Acetyl CoA
CoA
CoA
Citric
acid
cycle
FADH2
2 CO2
3 NAD+
3 NADH
+ 3 H+
FAD
ADP + P i
ATP
ATP
LE 9-6_3
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Glycolysis
Pyruvate
Glucose
Cytosol
Citric
acid
cycle
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
Mitochondrion
ATP
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Oxidative
phosphorylation
LE 9-13
NADH
50
Free energy (G) relative to O2 (kcal/mol)
FADH2
40
FMN
I
Multiprotein
complexes
FAD
Fe•S II
Fe•S
Q
III
Cyt b
30
Fe•S
Cyt c1
Glycolysis
Citric
acid
cycle
ATP
ATP
Oxidative
phosphorylation:
electron transport
and chemiosmosis
IV
Cyt c
Cyt a
ATP
Cyt a3
20
10
0
2 H+ + 1/2 O2
Activity: ETC
H2O
LE 9-15
Inner
mitochondrial
membrane
Glycolysis
Citric
acid
cycle
ATP
ATP
Oxidative
phosphorylation:
electron transport
and chemiosmosis
ATP
H+
H+
H+
H+
Intermembrane
space
Cyt c
Protein complex
of electron
carriers
Q
IV
III
I
ATP
synthase
II
Inner
mitochondrial
membrane
FADH2
NADH + H+
2H+ + 1/2 O2
H2O
FAD
NAD+
Mitochondrial
matrix
ATP
ADP + P i
(carrying electrons
from food)
H+
Electron transport chain
Electron transport and pumping of protons (H+),
Which create an H+ gradient across the membrane
Oxidative phosphorylation
Chemiosmosis
ATP synthesis powered by the flow
of H+ back across the membrane
LE 9-14
INTERMEMBRANE SPACE
H+
H+
H+
H+
H+
H+
A rotor within the
membrane spins
as shown when
H+ flows past
it down the H+
gradient.
H+
A stator anchored
in the membrane
holds the knob
stationary.
A rod (or “stalk”)
extending into
the knob also
spins, activating
catalytic sites in
the knob.
H+
ADP
+
P
ATP
i
MITOCHONDRAL MATRIX
Three catalytic
sites in the
stationary knob
join inorganic
phosphate to
ADP to make
ATP.
LE 9-16
Electron shuttles
span membrane
CYTOSOL
2 NADH
Glycolysis
Glucose
2
Pyruvate
MITOCHONDRION
2 NADH
or
2 FADH2
2 NADH
2
Acetyl
CoA
6 NADH
Citric
acid
cycle
+ 2 ATP
+ 2 ATP
by substrate-level
phosphorylation
by substrate-level
phosphorylation
Maximum per glucose:
About
36 or 38 ATP
2 FADH2
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
+ about 32 or 34 ATP
by oxidation phosphorylation, depending
on which shuttle transports electrons
form NADH in cytosol
LE 9-17a
2 ADP + 2 P i
Glucose
2 ATP
Glycolysis
2 Pyruvate
2 NAD+
2 Ethanol
Alcohol fermentation
2 NADH
+ 2 H+
2 CO2
2 Acetaldehyde
LE 9-17b
2 ADP + 2 P i
Glucose
2 ATP
Glycolysis
2 NAD+
2 NADH
+ 2 H+
2 CO2
2 Pyruvate
2 Lactate
Lactic acid fermentation
Activity: Fermentation
LE 9-18
Glucose
CYTOSOL
Pyruvate
No O2 present
Fermentation
O2 present
Cellular respiration
MITOCHONDRION
Ethanol
or
lactate
Acetyl CoA
Citric
acid
cycle
LE 9-19
Proteins
Carbohydrates
Amino
acids
Sugars
Glycerol Fatty
acids
Glycolysis
Glucose
Glyceraldehyde-3- P
NH3
Fats
Pyruvate
Acetyl CoA
Citric
acid
cycle
Oxidative
phosphorylation
LE 9-20
Glucose
AMP
Glycolysis
Fructose-6-phosphate
–
Stimulates
+
Phosphofructokinase
–
Fructose-1,6-bisphosphate
Inhibits
Inhibits
Pyruvate
ATP
Citrate
Acetyl CoA
Citric
acid
cycle
Oxidative
phosphorylation