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)

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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

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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

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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

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