Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. + + 2 1 5 4 GLUCOSE Pentose phosphate pathway Starts

~ ~

~ ~

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

+

+

2 1

5

4

GLUCOSE

Pentose phosphatepathway

Starts the oxidation of glucose

GlycolysisOxidizes glucose to pyruvate

Reducingpower

ATPby substrate-levelphosphorylation

FermentationReduces pyruvate

or a derivative

Biosynthesis

Transition step

Acetyl-CoA

Acetyl-CoA

RespirationUses the electron transportchain to convert reducing

power to proton motive force

ATPby oxidative

phosphorylation


Reducingpower

TCA cycleIncorporates an acetyl

group and releases CO2

(TCA cycles twice)

CO2 CO2

3a

X 2CO2

CO2

3b

Yields

Yields

Yields

Yields

Yields Reducingpower

Reducingpower

~ ~

Acids, alcohols, and gasesPyruvate Pyruvate



Ribose 5-phosphate

Erythrose 5-phosphate

Nucleotidesamino acids(histidine)

Amino acids(phenylalanine,tryptophan,tyrosine)

Lipids(glycerolcomponent)

Amino acids(cysteine,glycine, serine)

Amino acids(phenylalanine,tryptophan, tyrosine)

Amino acids(aspartate, asparagine,isoleucine, lysine,methionine, threonine)

TCA cycle

Amino acids(arginine, glutamate,glutamine, proline)

Lipids(fatty acids)

Amino acids(alanine,leucine, valine)

Peptidoglycan

Lipopolysaccharide(polysaccharide)

Glucose 6-phosphate

Fructose 6-phosphate

Dihydroxyacetonephosphate

3-phosphoglycerate

Phosphoenolpyruvate

Pyruvate

Acetyl-CoAAcetyl-CoA

Pyruvate

Oxaloacetate

- ketoglutarate

Glycolysis

X 2

The Central Metabolic Pathways

~ ~

~

~ ~

~

~

~ ~

~

~ ~

~

~ ~

~

~ ~

+

+

x2

PPP

PPP

PPP2 1

5

4

3b

~ ~

~ ~

~

GLUCOSE

Yields


or a derivative

PyruvatePyruvate

Reducingpower

Yields

Biosynthesis

Transition step3a

YieldsReducing

power

CO2

CO2

CO2CO2


group and releases CO2(TCA cycles twice)


Reducingpower

RespirationUses the electron transportChain to convert reducing


Yields

ATPby oxidative

phosphorylation

~

1

2

3

8

4

5

6

9

7

H2O

ATP is expended to add a phosphate group.

A chemical rearrangement occurs.

ATP is expended to add a phosphate group.

The 6-carbon molecule is split into two 3-carbonmolecules.

A chemical rearrangement of one of themolecules occurs.

The addition of a phosphategroup is coupled to a redoxreaction, generating NADH anda high-energy phosphate bond.

ATP is produced bysubstrate-levelphosphorylation.

A chemical rearrangement occurs.

Water is removed, causing thephosphate bond to becomehigh-energy.

ATP is produced bysubstrate-levelphosphorylation.

Pyruvate

ATP

ADP

Phospho-enolpyruvate

2-phospho-glycerate

3-phospho-glycerate

ATP

ADP

1,3-bisphospho-glycerate

Glyceraldehyde3-phosphate

Dihydroxyacetonephosphate

Fructose1,6-bisphosphate

ADP

ATP

Fructose6-phosphate

Glucose6-phosphate

10

H2O

NADH + H+

NAD+

Glucose

ATP

ADP

NADH + H+

NAD+




Reducingpower


Acids, alcohols, and gases

Yields

~ ~


• Glycolysis– Converts 1 glucose

to 2 pyruvates; yields net 2 ATP, 2 NADH

– Investment phase:• 2 phosphate groups

added• Glucose split to two 3-

carbon molecules

– Pay-off phase:• 3-carbon molecules

converted to pyruvate• Generates 4 ATP, • 2 NADH total

The Central Metabolic Pathways• Transition Step

– CO2 is removedfrom pyruvate

– Electrons reduce NAD+ toNADH + H+

– 2-carbon acetyl group joined to coenzyme A to form acetyl-CoA

– Takes place in mitochondria in eukaryotes


~~ ~ + Pi

H2O

1

2

8

7

6

5

3

4

A redox reactiongenerates NADH.

Water is added.

A redox reactiongenerates FADH2-

The energy releasedduring CoA removal isharvested to produce ATP.

ADPATP

CoA

A redox reactiongenerates NADH,CO2 is removed,and coenzyme Ais added.

A redox reactiongenerates NADHand CO2 isremoved.

A chemicalrearrangement occurs.

The acetyl group is transferredto oxaloacetate to start a newround of the cycle.

Transition step:CO2 is removed, a redox reaction generatesNADH, and coenzyme A is added.

NADH + H+

Acetyl-CoA

CoA

CoA

NADH + H+ Oxaloacetate

NAD+

Malate

Fumarate

FADH2

FAD Succinate Succinyl-CoACoA

CoA

CO2

NAD+

-ketoglutarate

Isocitrate

Citrate

CoA

NAD+

CO2

Pyruvate

NAD+

CO2

NADH + H+

NADH + H+

+

+

x 2

21

5

4

~ ~

~ ~

~ ~

GLUCOSE



ATPby oxidative

phosphorylation

Yields


Reducingpower

Yields

CO2

CO2

Pyruvate Pyruvate

3a Transition step


Acetyl-CoA

Acetyl-CoA

Biosynthesis

YieldsReducing

power




YieldsReducing

power


Acids, alcohols, and gases

CO2CO2


or a derivative



(TCA cycles twice)

3b

The Electron Transport Chain of MitochondriaCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 1

5

4



GLUCOSE





or a derivative

Acids, alcohols, and gasesPyruvatePyruvate

Reducingpower

Yields

Biosynthesis

Transition step3a


CO2CO2

Acetyl-CoA

Acetyl-CoA

CO2

CO2



(TCA cycles twice)

Yields


Reducingpower



Yields

ATPby oxidative

phosphorylation

x 2

3b

+PPP ~ ~

PPP

+

4 4 2 H+ 10 H+

+ 3 Pi

H2O

O22

e–

Eukaryotic cell

Innermitochondrialmembrane

Electron Transport Chain

Complex I

Ubiquinone

Complex III

NADHComplex II

3 ADP

3 ATP

Mitochondrialmatrix

Intermembranespace

Use of Proton Motive Force

ATP synthase(ATP synthesis)Complex IV

Proton motive forceis used to drive:

Terminalelectron acceptor

Cytochrome c

NAD+

H+H+

H+

H+ 1/2

Path ofelectrons

2

The Electron Transport Chain—Generating Proton Motive ForceCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

ve forcerive:

+

H+ H+

Terminal electron acceptor

–

O2

Prokaryotic cell

Cytoplasmicmembrane

Electron Transport Chain

NADH dehydrogenase

H+ (0 or 4)

Uses of Proton Motive Force

Rotation of a flagella

Outside ofcytoplasmicmembrane

Transportedmolecule

NADH

Cytoplasm

3 ADP

3 ATP

+ 3 Pi

NAD+

H+

Succinatedehydrogenase

Path ofelectrons

Ubiquinone

Active transport(one mechanism)

ATP synthase(ATP synthesis)Ubiquinol oxidase

H+ (2 or 4) 10 H+

H2O

2 H+

Proton motive forceis used to drive:

2 e–

1/2

Fig. 6.22

H

H

O

H3C C

O

HH3C C

HPyruvate Acetaldehyde Ethanol

H3C C C

O

O–

OH

NAD+

Lactate

CO2

NADH + NAD+H+

(a) Lactic acid fermentation

Pyruvate

H3C C

O O

C O–

OOH

O–H3C C C

NADH H+

+

+

x 2

PPP

PPP

PPP2 1

5

4

3b

~ ~

~ ~

~ ~Pentose phosphate

pathwayStarts the oxidation of glucose





or a derivative

Acids, alcohols, and gasesPyruvatePyruvate

Reducingpower

Yields

Biosynthesis

Transition step3a

YieldsReducing

power

CO2CO2

Acetyl-CoA

Acetyl-CoA

CO2

CO2



(TCA cycles twice)

Yields


Reducingpower



Yields

ATPby oxidative

phosphorylation

(b) Ethanol fermentation


+

GLUCOSE

Documents

~~ ~~ Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. + + 2 1 5 4 GLUCOSE Pentose phosphate pathway Starts

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. + + 2 1 5 4 GLUCOSE Pentose phosphate pathway Starts