Chap 7 Diagrams

1

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Product

Enzyme

NAD+

NAD+ NAD NAD

2e–

H+

+H+

Energy-rich

molecule

NAD+

1. Enzymes that use NAD+

as a cofactor for oxidation

reactions bind NAD+ and the

substrate.

2. In an oxidation–reduction

reaction, 2 electrons and

a proton are transferred

to NAD+, forming NADH.

A second proton is

donated to the solution.

3. NADH diffuses away

and can then donate

electrons to other

molecules.

Reduction

Oxidation

H H

H H

H

H

H H

2

2e–

Electrons from food

High energy

Low energy

2H+ 1 / 2 O2

Energy released

for ATP synthesis

H2O


3


H H

O

NH2 + 2H

CH2 O

O

O

H

H

NH2

H

H

N

N

N

CH2 O

O

O

H

H

NH2

O–

H

H

N N

N

H H O

N

N

H H

H

C C

O P

O P O– O P

O– O P

N N

OH

CH2

NADH: Reduced form of nicotinamide

O

O O

O

NAD+: Oxidized form of nicotinamide

Reduction

Oxidation

Adenine Adenine

OH OH

OH OH OH

OH OH

NH2 + H+

CH2

O–

4

PEP

– ADP

Enzyme Enzyme

– ATP P

P

P

Adenosine


5

Outer

mitochondrial

membrane

Intermembrane

space

Mitochondrial

matrix

FAD O2

Inner

mitochondrial

membrane

Electron

Transport Chain Chemiosmosis

ATP Synthase

NAD+

Glycolysis

Pyruvate

Glucose

Pyruvate

Oxidation

Acetyl-CoA

Krebs

Cycle

CO2

ATP H2O

ATP

e–

e–

NADH

NADH

CO2

ATP

NADH

FADH2


H+

e–

6


Glycolysis

NADH

Pyruvate Oxidation

ATP

Electron Transport Chain Chemiosmosis

Krebs Cycle

6-carbon sugar diphosphate

NAD+ NAD+

Pri

min

g R

ea

cti

on

s

Cle

ava

ge

O

xid

ati

on

an

d A

TP

Fo

rma

tio

n

NADH NADH

P P

P P

ATP ATP

ADP ADP

3-carbon sugar

phosphate

3-carbon sugar

phosphate

Pi Pi

ADP ADP

ATP ATP

ATP

ADP ADP

ATP

3-carbon

pyruvate

3-carbon

pyruvate

6-carbon glucose

(Starting material)

Glycolysis begins

with the addition of

energy. Two high-

energy phosphates

(P) from two

molecules of ATP

are added to the

6-carbon molecule

glucose, producing

a 6-carbon

molecule with two

phosphates.

Then, the 6-carbon

molecule with two

phosphates is split in

two, forming two

3-carbon sugar

phosphates.

An additional

Inorganic phosphate

( Pi ) is incorporated

into each 3-carbon

sugar phosphate. An

oxidation reaction

converts the two

sugar phosphates

into intermediates

that can transfer a

phosphate to ADP to

form ATP. The

oxidation reactions

also yield NADH

giving a net energy

yield of 2 ATP and 2

NADH.

7


NADH

NAD+

NADH

Pi NAD+

Glucose

Hexokinase

Phosphofructokinase

Glucose 6-phosphate

Fructose 6-phosphate

Fructose 1,6-bisphosphate

Isomerase Aldolase

Pyruvate Pyruvate

Enolase

Pyruvate kinase

AD P

10

Glu

cose

Gly

cera

ldeh

yde

3-

ph

osp

hat

e

Pyr

uva

te

Glycolysis: The Reactions Glycolysis

NADH

Pyruvate Oxidation

H2O

ATP

ADP


Krebs Cycle

ATP

ATP

Phosphoglucose isomerase

Glyceraldehyde 3- phosphate (G3P)

Dihydroxyacetone phosphate

1. Phosphorylation of glucose by ATP.

2–3. Rearrangement, followed by a second ATP phosphorylation.

4–5. The 6-carbon molecule is split into two 3-carbon molecules—one G3P, another that is converted into G3P in another reaction.

6. Oxidation followed by phosphorylation produces two NADH molecules and two molecules of BPG, each with one high-energy phosphate bond.

7. Removal of high-energy phosphate by two ADP molecules produces two ATP molecules and leaves two 3PG molecules.

8–9. Removal of water yields two PEP molecules, each with a high-energy phosphate bond.

10. Removal of high-energy phosphate by two ADP molecules produces two ATP molecules and two pyruvate molecules.

1,3-Bisphosphoglycerate (BPG)

1,3-Bisphosphoglycerate (BPG)

Glyceraldehyde 3-phosphate

dehydrogenase

Pi

ADP

Phosphoglycerate kinase

ADP

ATP

3-Phosphoglycerate (3PG)




H2O

ATP

Phosphoenolpyruvate (PEP)

Phosphoenolpyruvate (PEP)

ADP ADP

ATP ATP

Ph

osp

ho

en

ol-

p

yru

vate

3-

Ph

osp

ho

- gl

yce

rate

1,

3-B

isp

ho

sph

o-

glyc

era

te

Glu

cose

6-

ph

osp

hat

e

Fru

cto

se

6-p

ho

sph

ate

Fr

uct

ose

1,

6-b

isp

ho

sph

ate

D

ihyd

roxy

ace

ton

e

Ph

osp

hat

e

2-P

ho

sph

o-

glyc

era

te

CH2OH

O

CH2 O

O

P

CH2 O

O

P

CH2OH

O CH2 CH2 O

O

P P

CHOH

H

C O

CH2 O P

C O

O CH2 P

CH2OH

CHOH

O C O

CH2 O

P

P

CHOH

O–

C O

CH2 O P

H C O

O–

C O

CH2OH

P

C O

O–

C O

CH2

P

C O

O–

C O

CH3

8

9

10

7

4 5

3

2

1

6

Phosphoglyceromutase

8


Without oxygen

NAD+

O2 NADH

ETC in mitochondria

Acetyl-CoA

Ethanol

NAD+

CO2

NAD+

H2O

Lactate

Pyruvate

Acetaldehyde NADH

NADH

With oxygen

Krebs Cycle

9


Glycolysis

Pyruvate Oxidation

NADH

Krebs Cycle


Pyruvate Oxidation: The Reaction

NAD+

CO2

CoA

Acetyl Coenzyme A

Pyruvate

Pyru

vate

A

cety

l C

oen

zym

e A

O

CH 3

C

O–

C O

S CoA

CH3

O C

NADH

10


CoA-

(Acetyl-CoA) CoA

4-carbon

molecule

(oxaloacetate) 6-carbon molecule

(citrate)

NAD +

NADH

CO2

5-carbon

molecule

NAD+

NADH

CO2

4-carbon

molecule

ADP + P

Krebs Cycle

FAD

FADH2

4-carbon

molecule

NAD+

NADH

ATP

Glycolysis

Pyruvate Oxidation


ATP

4-carbon

molecule

Pyruvate from glycolysis is

oxidized Krebs Cycle into an

acetyl group that feeds into the

Krebs cycle. The 2-C acetyl group

combines with 4-C oxaloacetate to

produce the 6-C compound citrate

(thus this is also called the citric

acid cycle). Oxidation reactions

are combined with two

decarboxylations to produce

NADH, CO2, and a new 4-carbon

molecule. Two additional

oxidations generate another

NADH and an FADH2 and

regenerate the original 4-C

oxaloacetate.

NADH

FADH2

Krebs

Cycle

11


Glycolysis

NADH

F ADH2

Pyruvate Oxidation

ATP

Krebs Cycle: The Reactions

Citrate synthetase

NAD+

NADH

H2O

NAD+

NADH

CO2

Isocitrate dehydrogenase

Fumarase

CoA-SH 1

2

Aconitase 3

4

8

9

7

CoA-SH

NAD+

CO2

5

6

NADH

CoA-SH

GDP + Pi

Acetyl-CoA

═

CH3 — C — S

O CoA —

Krebs

Cycle

Malate

dehydrogenase

-Ketoglutarate

dehydrogenase

Succinyl-CoA

synthetase

GTP

ATP

ADP

Succinate

dehydrogenase

FADH2

8–9. Reactions 8 and 9: Regeneration of

oxaloacetate and the fourth oxidation

7. Reaction 7: The third oxidation

6. Reaction 6: Substrate-level phosphorylation

5. Reaction 5: The second oxidation

4. Reaction 4: The first oxidation

2–3. Reactions 2 and 3: Isomerization

1. Reaction 1: Condensation

Electron T ransport Chain Chemiosmosis

Oxaloacetate (4C)

CH2

O ═ C

COO—

COO—

—

—

—

Citrate (6C)

HO — C — COO—

COO—

COO—

CH2

CH2

—

—

—

—

Isocitrate (6C)

HC — COO—

COO—

COO—

CH2

HO — CH

—

—

—

—

-Ketoglutarate (5C)

CH2

COO—

COO—

CH2

C — O —

—

—

—

Succinyl-CoA (4C)

CH2

COO—

S — CoA

CH2

C ═ O

— —

—

—

Succinate (4C)

COO—

CH2

COO—

CH2

— —

—

Fumarate (4C)

HC

CH

═

COO—

COO—

—

—

Malate (4C)

HO — CH

COO—

CH2

COO—

— —

—

FAD

12


Mitochondrial matrix

NADH + H+

ADP + Pi H2O

H+ H+

2H+ + 1 / 2 O2

Glycolysi s

Pyruvate Oxidatio n

2

Krebs Cycle ATP


NADH dehydrogenase bc1 complex Cytochrome

oxidase complex

Inner mitochondrial membrane

Intermembrane space

a. The electron transport chain

ATP synthase

b. Chemiosmosis

NAD+

Q

C

e–

FADH2

H+ H+

H+ H+

e– 2 2 e– 2 2

ATP

FAD

13

ADP + Pi

Catalytic head

Stalk

Rotor

H+

H+

Mitochondrial matrix

Intermembrane space

H+ H+

H+

H+ H+

ATP


14


H2O

CO2

CO2

H+

H+

2H+

+ 1 / 2 O2

H+

e–

H+

32 ATP

Krebs Cycle

2 ATP

NADH

NADH

FADH2

NADH

Pyruvate Oxidation

Acetyl-CoA

e–

Q

C

e–

Glycolysis

Glucose

Pyruvate

15

Chemiosmosis

Chemiosmosis

2 5

2 3

6 15

2

2

2 5 NADH

NADH

NADH

Total net ATP yield = 32 (30 in eukaryotes)

ATP

ATP

ATP

ATP

ATP

ATP

Krebs Cycle

Pyruvate oxidation

FADH2

Glycolysis 2

Glucose

Pyruvate

ATP


16

Glucose

Acetyl-CoA

Fructose 6-phosphate

Fructose 1,6-bisphosphate

Pyruvate

Pyruvate Oxidation

Krebs Cycle

Electron Transport Chain and

Chemiosmosis

Citrate

ATP

NADH

Inhibits

Inhibits Inhibits

Phosphofructokinase

Pyruvate dehydrogenase

Glycolysis


ADP

Activates

17

CO2

2 Acetaldehyde

2 AD P

2 Lactate

Alcohol Fermentation in Yeast

2 ADP

Lactic Acid Fermentation in Muscle Cells

2 NAD+

2 NAD+

2 NADH

2 NADH

2 ATP

2 ATP

C O

C O

O–

CH3

C O

H

CH3

C O

C O

CH3

O–

CH3

H C OH

C O

O–

H

2 Ethanol

H C OH

CH3

2 Pyruvate

2 Pyruvate

Glucose

Glucose

G

L

Y

C

O

L

Y

S

I

S

G

L

Y

C

O

L

Y

S

I

S


18

C

HO O

HO O

C

C

HO O

O

C

C O

C H H

C H H C H H

C H H

C H2N H

NH3

HO

Urea

Glutamate α-Ketoglutarate


19


CoA

Fatty acid

O O

— C — C — C —

═

H

H

—

═

—

ATP

NADH

H2O

Krebs

Cycle

PPi AMP +

FADH2

Fatty acid

2C shorter

CoA

CoA

Fatty acid

O H

H

— C — C — C —

— —

H

H

—

═

—

Fatty acid

OH

O H

H

— C — C — C

— —

H

H

— —

CoA

FAD

Fatty acid

O H

— C ═ C — C —

—

H —

═

CoA

Fatty acid

O HO

H

— C — C — C —

— —

H

H

—

═

—

CoA

NAD+

Acetyl-CoA

20

Cell building blocks

Deamination -oxidation Glycolysis

Oxidative respiration

Ultimate metabolic products

Acetyl-CoA

Pyruvate

Macromolecule

degradation

Krebs

Cycle

Nucleic acids Polysaccharides

Nucleotides Amino acids Fatty acids Sugars

Proteins Lipids and fats

NH3 H2O CO2


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Chap 7 Diagrams