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Fig. 9-1
Are you the “slow-twitch” or “fast-twitch”?
Barbara Radcliffe2:15:25
London 2003
2009 World Championships Berlin, Germany
Usain Bolt9.58
Fast twitch muscle slow twitch muscle
Less myoglobinLess mitochondria
More myoglobinMore mitochondria
What makes these muscle fibers different?
• The process for making ATP varies
• Slow fibers do it aerobically (O2)
• Fast fibers w/o O2 (anaerobic)
• # of mitochondrion vary, amt. of myoglobin
Efficiency of Cellular Respiration
• 36-38 ATP per glucose molecule
• 40% of energy from glucose is harvested
• 60% heat
• 1 muscle cell spends/regenerates 10 million ATP/sec
Fig. 9-2
Lightenergy
ECOSYSTEM
Photosynthesis in chloroplasts
CO2 + H2O
Cellular respirationin mitochondria
Organicmolecules+ O2
ATP powers most cellular work
Heatenergy
ATP
• C6H12O6 + 6 O2 6 CO2 + 6 H2O + Energy
• Energy = (ATP + heat)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 9-UN2
becomes oxidized
becomes reduced
Fig. 9-UN1
becomes oxidized(loses electron)
becomes reduced(gains electron)
Oxidation of Organic Fuel Molecules During Cellular Respiration
• During cellular respiration, the fuel (such as glucose) is oxidized and becomes CO2, and O2 is reduced forming H2O:
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 9-UN3
becomes oxidized
becomes reduced
The Stages of Cellular Respiration: A Preview
• Cellular respiration has three stages:
– Glycolysis (breaks down glucose into two molecules of pyruvate)
– The citric acid cycle (completes the breakdown of glucose) or Krebs Cycle
– Oxidative phosphorylation (accounts for most of the ATP synthesis) or ETC
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Glucose + oxygen
Glycolysis Krebs CycleElectron
TransportChain
Carbon dioxide+
water
Fig. 9-6-3
Mitochondrion
Substrate-levelphosphorylation
ATP
Cytosol
Glucose Pyruvate
Glycolysis
Electronscarried
via NADH
Substrate-levelphosphorylation
ATP
Electrons carriedvia NADH and
FADH2
Oxidativephosphorylation
ATP
Citricacidcycle
Oxidativephosphorylation:electron transport
andchemiosmosis
Concept 9.2: Glycolysis harvests chemical energy by oxidizing glucose to pyruvate
• Glycolysis (“splitting of sugar”) breaks down glucose into two molecules of pyruvate
• Glycolysis occurs in the cytoplasm and has two major phases:
– Energy investment phase
– Energy payoff phase
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 9-11
Pyruvate
NAD+
NADH
+ H+Acetyl CoA
CO2
CoA
CoA
CoA
Citricacidcycle
FADH2
FAD
CO22
3
3 NAD+
+ 3 H+
ADP + P i
ATP
NADH
Fig. 9-13
NADH
NAD+2FADH2
2 FADMultiproteincomplexesFAD
Fe•S
FMN
Fe•S
Q
Fe•S
Cyt b
Cyt c1
Cyt c
Cyt a
Cyt a3
IV
Fre
e en
erg
y (G
) r e
lat i
ve t
o O
2 (
kcal
/mo
l)
50
40
30
20
10 2
(from NADHor FADH2)
0 2 H+ + 1/2 O2
H2O
e–
e–
e–
Fig. 9-14
INTERMEMBRANE SPACE
Rotor
H+
Stator
Internalrod
Cata-lyticknob
ADP+P ATP
i
MITOCHONDRIAL MATRIX
Fig. 9-16
Protein complexof electroncarriers
H+
H+H+
Cyt c
Q
V
FADH2 FAD
NAD+NADH
(carrying electronsfrom food)
Electron transport chain
2 H+ + 1/2O2H2O
ADP + P i
Chemiosmosis
Oxidative phosphorylation
H+
H+
ATP synthase
ATP
21
• In alcohol fermentation, pyruvate is converted to ethanol in two steps, with the first releasing CO2
• Alcohol fermentation by yeast is used in brewing, winemaking, and baking
Animation: Fermentation OverviewAnimation: Fermentation Overview
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings