Chp 9: Cellular Respiration

Figure 9-01

LE 9-2

ECOSYSTEM

Lightenergy

Photosynthesisin chloroplasts

Cellular respirationin mitochondria

Organicmolecules+ O2

CO2 + H2O

ATP

powers most cellular work

Heatenergy

LE 9-6_3

Mitochondrion

Glycolysis

PyruvateGlucose

Cytosol

ATP

Substrate-levelphosphorylation

ATP

Substrate-levelphosphorylation

Citricacidcycle

ATP

Oxidativephosphorylation

Oxidativephosphorylation:electron transport

andchemiosmosis

Electronscarried

via NADH

Electrons carriedvia NADH and

FADH2

Activity: Overview

LE 9-7

Enzyme

ADP

P

Substrate

Product

Enzyme

ATP+

LE 9-UN161a

becomes oxidized(loses electron)

becomes reduced(gains electron)

LE 9-UN161

becomes oxidized

becomes reduced

LE 9-3

Reactants

becomes oxidized

becomes reduced

Products

H

Methane(reducing

agent)

Oxygen(oxidizing

agent)

Carbon dioxide Water

H C H

H

O O O OC OH H

CH4 2 O2+ ++CO2Energy 2 H2O

LE 9-UN162a

becomes reduced

becomes oxidized

LE 9-UN162b

Dehydrogenase

LE 9-4

NAD+

Nicotinamide(oxidized form)

Dehydrogenase

2 e– + 2 H+

2 e– + H+

NADH H+

H+

Nicotinamide(reduced form)

+ 2[H](from food)

+

LE 9-5

2 H+ + 2 e–

2 H

(from food via NADH)

Controlledrelease ofenergy for

synthesis ofATP ATP

ATP

ATP

2 H+

2 e–

H2O

+ 1/2 O21/2 O2H2 +

1/2 O2

H2O

Explosiverelease of

heat and lightenergy

Cellular respirationUncontrolled reaction

Fre

e en

erg

y, G

Fre

e en

erg

y, G

Electro

n tran

spo

rt chain

LE 9-UN164

Glycolysis (color-coded teal throughout the chapter)

Oxidation phosphorylation: electron transport andchemiosmosis (color-coded violet)

1.

2.

3.

The citric acid cycle (color-coded salmon)

LE 9-6_3

Mitochondrion

Glycolysis

PyruvateGlucose

Cytosol

ATP

Substrate-levelphosphorylation

ATP

Substrate-levelphosphorylation

Citricacidcycle

ATP

Oxidativephosphorylation

Oxidativephosphorylation:electron transport

andchemiosmosis

Electronscarried

via NADH

Electrons carriedvia NADH and

FADH2

LE 9-8

Energy investment phase

Glucose

2 ATP used2 ADP + 2 P

4 ADP + 4 P 4 ATP formed

2 NAD+ + 4 e– + 4 H+

Energy payoff phase

+ 2 H+2 NADH

2 Pyruvate + 2 H2O

2 Pyruvate + 2 H2O

2 ATP

2 NADH + 2 H+

Glucose

4 ATP formed – 2 ATP used

2 NAD+ + 4 e– + 4 H+

Net

Glycolysis Citricacidcycle

Oxidativephosphorylation

ATPATPATP

Activity: Glycolysis

LE 9-10

CYTOSOL

Pyruvate

NAD+

MITOCHONDRION

Transport protein

NADH + H+

Coenzyme ACO2

Acetyl Co A

LE 9-12_4

ATP ATP ATP

Glycolysis Oxidationphosphorylation

Citricacidcycle

Citricacidcycle

Citrate

Isocitrate

Oxaloacetate

Acetyl CoA

H2O

CO2

NAD+

NADH

+ H+

-Ketoglutarate

CO2NAD+

NADH

+ H+SuccinylCoA

Succinate

GTP GDP

ADP

ATP

FAD

FADH2

P i

Fumarate

H2O

Malate

NAD+

NADH

+ H+

Activity: Citric Acid Cycle (Krebs Cycle)

LE 9-11Pyruvate(from glycolysis,2 molecules per glucose)

ATP ATP ATP

Glycolysis Oxidationphosphorylation

CitricacidcycleNAD+

NADH

+ H+

CO2

CoA

Acetyl CoACoA

CoA

Citricacidcycle

CO22

3 NAD+

+ 3 H+

NADH3

ATP

ADP + P i

FADH2

FAD

LE 9-6_3

Mitochondrion

Glycolysis

PyruvateGlucose

Cytosol

ATP

Substrate-levelphosphorylation

ATP

Substrate-levelphosphorylation

Citricacidcycle

ATP

Oxidativephosphorylation

Oxidativephosphorylation:electron transport

andchemiosmosis

Electronscarried

via NADH

Electrons carriedvia NADH and

FADH2

LE 9-13

ATP ATP ATP

GlycolysisOxidative

phosphorylation:electron transportand chemiosmosis

Citricacidcycle

NADH

50

FADH2

40 FMN

Fe•S

I FAD

Fe•S II

IIIQ

Fe•S

Cyt b

30

20

Cyt c

Cyt c1

Cyt a

Cyt a3

IV

10

0

Multiproteincomplexes

Fre

e en

erg

y (G

) re

lati

ve t

o O

2 (k

cal/m

ol)

H2O

O22 H+ + 1/2

Activity: ETC

LE 9-15

Protein complexof electroncarriers

H+

ATP ATP ATP

GlycolysisOxidative

phosphorylation:electron transportand chemiosmosis

Citricacidcycle

H+

Q

IIII

II

FADFADH2

+ H+NADH NAD+

(carrying electronsfrom food)

Innermitochondrialmembrane

Innermitochondrialmembrane

Mitochondrialmatrix

Intermembranespace

H+

H+

Cyt c

IV

2H+ + 1/2 O2 H2O

ADP +

H+

ATP

ATPsynthase

Electron transport chainElectron transport and pumping of protons (H+),

Which create an H+ gradient across the membrane

P i

ChemiosmosisATP synthesis powered by the flow

of H+ back across the membrane

Oxidative phosphorylation

LE 9-14

INTERMEMBRANE SPACE

H+ H+

H+H+

H+

H+

H+

H+

ATP

MITOCHONDRAL MATRIX

ADP+

Pi

A rotor within the membrane spins as shown when H+ flows past it down the H+ gradient.

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.

Three catalytic sites in the stationary knob join inorganic phosphate to ADP to make ATP.

LE 9-16

CYTOSOL Electron shuttlesspan membrane 2 NADH

or

2 FADH2

MITOCHONDRION

Oxidativephosphorylation:electron transport

andchemiosmosis

2 FADH22 NADH 6 NADH

Citricacidcycle

2AcetylCoA

2 NADH

Glycolysis

Glucose2

Pyruvate

+ 2 ATP

by substrate-levelphosphorylation

+ 2 ATP

by substrate-levelphosphorylation

+ about 32 or 34 ATP

by oxidation phosphorylation, dependingon which shuttle transports electronsform NADH in cytosol

About36 or 38 ATPMaximum per glucose:

LE 9-17a

CO2

+ 2 H+

2 NADH2 NAD+

2 Acetaldehyde

2 ATP2 ADP + 2 P i

2 Pyruvate

2

2 Ethanol

Alcohol fermentation

Glucose Glycolysis

LE 9-17b

CO2

+ 2 H+

2 NADH2 NAD+

2 ATP2 ADP + 2 P i

2 Pyruvate

2

2 Lactate

Lactic acid fermentation

Glucose Glycolysis

Activity: Fermentation

LE 9-18

Pyruvate

Glucose

CYTOSOL

No O2 presentFermentation

Ethanolor

lactate

Acetyl CoA

MITOCHONDRION

O2 present Cellular respiration

Citricacidcycle

LE 9-19

Citricacidcycle

Oxidativephosphorylation

Proteins

NH3

Aminoacids

Sugars

Carbohydrates

Glycolysis

Glucose

Glyceraldehyde-3- P

Pyruvate

Acetyl CoA

Fattyacids

Glycerol

Fats

LE 9-20

Citricacidcycle

Oxidativephosphorylation

Glycolysis

Glucose

Pyruvate

Acetyl CoA

Fructose-6-phosphate

Phosphofructokinase

Fructose-1,6-bisphosphate

–

Inhibits

ATP Citrate

Inhibits

Stimulates

AMP

+

–