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CHAPTER 7

LECTURE

SLIDES

Prepared by

Brenda Leady University of Toledo

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2

Cellular respiration

Process by which living cells obtain energy

from organic molecules

Primary aim to make ATP and NADH

Aerobic respiration uses oxygen

O2 consumed and CO2 released

Focus on glucose but other organic

molecules also used

3

Glucose metabolism

C6H12O6 + 6O2 → 6CO2 + 6H2O

4 metabolic pathways

1. Glycolysis

2. Breakdown of pyruvate to an acetyl group

3. Citric acid cycle

4. Oxidative phosphorylation

4

1

2 pyruvate

2 pyruvate

C C C C C C

C C C 2

2

2 acetyl

C C C 2

C C 2

2 pyruvate

2 CO2

2 CO2

2 CO2

3

4 CO2

C C 2

2 acetyl

Cytosol

2 NADH

2 NADH

+2 ATP

Via chemiosmosis

6 NADH 2 FADH2

Glycolysis:

Glucose

Outer mitochondrial

membrane

Breakdown of

pyruvate:

2CO2 + 2acetyl

Citric acid

cycle:

Via substrate-level

phosphorylation Via substrate-level

phosphorylation

Mitochondrial

matrix Inner mitochondrial

membrane

+2 ATP +30–34 ATP

4 Oxidative

phosphorylation:

The oxidation of NADH

and FADH2 via the

electron transport

chain provides energy

to make more ATP

via the ATP synthase.

O2 is consumed.


5

Stage 1: Glycolysis

Glycolysis can occur with or without oxygen

Steps in glycolysis nearly identical in all living species

10 steps in 3 phases

1. Energy investment

2. Cleavage

3. Energy liberation

6

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7

3 phases of glycolysis

1. Energy investment Steps 1-3

2 ATP hydrolyzed to create fructose-1,6 bisphosphate

2. Cleavage Steps 4-5

6 carbon molecule broken into two 3 carbon molecules of glyceraldehyde-3-phosphate

3. Energy liberation Steps 6-10

Two glyceraldehyde-3-phosphate molecules broken down into two pyruvate molecules producing 2 NADH and 4 ATP

Net yield in ATP of 2

8

C C C C C C

Glucose

OH H

H OH H

OH

O H H

HO

CH2OH


9

ATP ATP

C C C C C C C C C C C C

Energy investment phase

Step 2 Step 3 Step 1

Glucose Fructose-1,6-

bisphosphate

OH H

H OH H

OH

O H H

HO

CH2OH

H HO

OH

OH

H

H

OCH2 P P O CH2O


10

C C C ATP


C C C

Cleavage phase Energy investment phase

Step 4 Step 5



bisphosphate

OH H

H OH H

OH

O H H

HO

CH2OH

ATP

H HO

OH

OH

H

H

OCH2 P P O CH2O

P

CHOH

C

H

O

CH2O

P

CHOH

H

O C

CH2O

Two molecules of

glyceraldehyde-

3-phosphate


11

C C C

Pi

ATP ATP

NADH ATP ATP

NADH ATP ATP


C C C C C C

C C C

C O

C O

O–

CH3

C O

C O

O–

CH3

Cleavage phase Energy investment phase

Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10

Energy liberation phase



bisphosphate

OH H

H OH H

OH

O H H

HO

CH2OH

H HO

OH

OH

H

H

OCH2 P P O CH2O

P

CHOH

C

H

O

CH2O

Pi

Two molecules

of pyruvate

P

CHOH

H

O C

CH2O

Two molecules of

glyceraldehyde-

3-phosphate


12

ATP

OH H

H OH H

OH

O H H

HO

Glucose

CH2OH


13

ATP ADP

OH H

H OH

H

OH

O H H

HO

OCH2 P

Hexokinase OH H

H OH

H

OH

O H H

HO

Glucose

CH2OH

Glucose-6-phosphate


14

ATP ADP ATP

Hexokinase

Glucose

OH H

H OH H

OH

O H H

HO

CH2OH

Glucose-6-phosphate

Phosphogluco–

isomerase

Fructose-6-phosphate

OH H

H OH H

OH

O H H

HO

OCH2 P

HO

OH

OH

H

H H

OCH2 P

CH2OH O


15

ATP ADP ATP

ADP

Hexokinase Aldolase

- -

OH H

H OH H

OH

O H H

HO

Glucose

CH2OH

Glucose-6-phosphate

Phosphogluco–

isomerase


Phosphofructo–

kinase

Fructose-1,6-bisphosphate

OH H

H OH H

OH

O H H

HO

OCH2 P

OH H

HO OH

H H

OCH2 P

CH2OH O

HO

OH

OH

H

H H

OCH2 P P CH2O O


16

ATP ADP ATP

ADP

OH H

H OH H

OH

O H H

HO

OCH2 P

Hexokinase Aldolase

- -

Isomerase

OH H

H OH H

OH

O H H

HO

Glucose

CH2OH

Glucose-6-phosphate

Phosphogluco–

isomerase


Phosphofructo–

kinase


P

CHOH

H

C O

CH2O

Glyceraldehyde-3-

phosphate (× 2)

Dihydroxyacetone

phosphate

C O

OCH 2 P

CH2OH

HO

OH

OH

H

H H

OCH2 P

CH2OH O

HO

OH

OH

H

H H

OCH2 P P CH2O O



2 NADH

2 NADH

6 NADH

Glucose

Glycolysis:

2

2

+2 ATP

2 pyruvate 2

2 FADH2

Break-

down of

pyruvate

+2 ATP

Citric acid

cycle

+30–34 ATP

Oxidative

phosphorylation

ATP ADP ATP

ADP

OH H

H OH H

OH

O H H

HO

OCH2 P

CO2

CO2

Hexokinase Aldolase

- -

Isomerase

OH H

H OH H

OH

O H H

HO

Glucose

CH2OH

Glucose-6-phosphate

Phosphogluco–

isomerase


Phosphofructo–

kinase


P

CHOH

H

C O

CH2O

Glyceraldehyde-3-

phosphate (× 2)

Dihydroxyacetone

phosphate

C O

OCH 2 P

CH2OH

CO2

HO

OH

OH

H

H H

OCH2 P

CH2OH O

HO

OH

OH

H

H H

OCH2 P P CH2O O

17

18

Isomerase

P CHOH

H C O CH2O

Glyceraldehyde-3-

phosphate (× 2)

Dihydroxyacetone

phosphate

C O OCH2 P

CH2OH


19

Isomerase

P

CHOH

H

C O

CH2O

Glyceraldehyde-3-

phosphate (× 2)

Dihydroxyacetone

phosphate

C O

OCH2 P

CH2OH

2 Pi

2 NAD+ +2 H+

2 NADH

Unstable phosphate bond

Glyceraldehyde-

3-phosphate

dehydrogenase

~

P

CHOH

O OC P

CH2O

1, 3 -bisphosphoglycerate

( × 2 )


20

2 ATP

Isomerase

P

CHOH

H

C O

CH2O

Glyceraldehyde-3-

phosphate (× 2)

Dihydroxyacetone

phosphate

C O

OCH2 P

CH2OH

2 ADP

2 Pi

2 NAD+ +2 H+

2 NADH


Glyceraldehyde-

3-phosphate

dehydrogenase

~

P

CHOH

O OC P

CH2O


( × 2 )

Phosphoglycero–

kinase

P

CHOH

O C

O

CH2O

3-phosphoglycerate

( × 2 )


21

2 ATP

Isomerase

P

CHOH

H

C O

CH2O

Glyceraldehyde-3-

phosphate (× 2)

Dihydroxyacetone

phosphate

C O

OCH2 P

CH2OH

2 ADP

2 Pi

2 NAD+ +2 H+

P HCO

O C

O–

CH 2 OH

2 NADH

Phosphoglycer o – mutase


Glyceraldehyde-

3-phosphate

dehydrogenase

~

P

CHOH

O OC P

CH2O


( × 2 )

Phosphoglycero–

kinase

P

CHOH

O C

O

CH2O

3-phosphoglycerate

( × 2 )

2-phosphoglycerate

( × 2 )


22

2 ATP

Isomerase

P

CHOH

H

C O

CH2O

Glyceraldehyde-3-

phosphate (× 2)

Dihydroxyacetone

phosphate

C O

OCH2 P

CH2OH

2 ADP

2 Pi

2 NAD+ +2 H+

P HCO

O C

O–

CH 2 OH

~ P CO

O C

O–

CH2

2 NADH


Enolase

Unstable phosphate bond Unstable phosphate bond

Glyceraldehyde-

3-phosphate

dehydrogenase

~

P

CHOH

O OC P

CH2O


( × 2 )

Phosphoglycero–

kinase

P

CHOH

O C

O

CH2O

3-phosphoglycerate

( × 2 )

2-phosphoglycerate

( × 2 )

2 H2O

Phosphoenolpyruvate

( × 2 )


23

2 ATP 2 ATP

Isomerase

P

CHOH

H

C O

CH2O

Glyceraldehyde-3-

phosphate (× 2)

Dihydroxyacetone

phosphate

C O

OCH2 P

CH2OH

2 ADP 2 ADP

2 Pi

2 NAD+ +2 H+

P HCO

O C

O–

CH 2 OH

~ P CO

O C

O–

CH2

O C

O–

CH3

O C

2 NADH


Enolase Pyruvate kinase

Unstable phosphate bond Unstable phosphate bond

Glyceraldehyde-

3-phosphate

dehydrogenase

~

P

CHOH

O OC P

CH2O


( × 2 )

Phosphoglycero–

kinase

P

CHOH

O C

O

CH2O

3-phosphoglycerate

( × 2 )

2-phosphoglycerate

( × 2 )

2 H2O

Phosphoenolpyruvate

( × 2 )

Pyruvate

( × 2 )


24

Stage 2: Breakdown of pyruvate to

an acetyl group

In eukaryotes, pyruvate in transported to

the mitochondrial matrix

Broken down by pyruvate dehydrogenase

Molecule of CO2 removed from each

pyruvate

Remaining acetyl group attached to CoA

to make acetyl CoA

1 NADH is made for each pyruvate

25

H+

O C

O–

CH3

O C

NADH +

NAD+ + + CoA SH

CO2

Acetyl CoA

Outer

membrane

channel

H+/pyruvate

symporter

Pyruvate

dehydrogenase

O

CoA

C

S

CH3

+

O C

O–

CH3

O C


26

Stage 3: Citric acid cycle

Metabolic cycle Particular molecules enter while other leave,

involving a series of organic molecules regenerated with each cycle

Acetyl is removed from Acetyl CoA and attached to oxaloacetate to form citrate or citric acid

Series of steps releases 2CO2, 1ATP, 3NADH, and 1 FADH2

Oxaloacetate is regenerated to start the cycle again

27

Citric acid cycle

GTP

ATP

5

NADH

CO2

CO2

3

4

C C C C C

1

2

C C C C

NADH

8

C C C C 7

C C C C

FADH2

6

C C C C

+2 ATP

2 CO2

2 NADH

2 NADH

6 NADH 2 FADH2

2 CO2

2 CO2

+2 ATP

2 pyruvate

C C C C

+30–34 ATP


NADH

Acetyl CoA

Oxaloacetate

Citrate

Glycolysis:

Glucose

Break-

down of

pyruvate

Oxidative

phosphorylation

O

C S CoA H2C

Citric

acid

cycle


28

Acetyl CoA

CoA—SH

C C

CoA

C

S

O

CH +

1

H2O

Citrate

synthetase


29

Acetyl CoA

CoA—SH

C C

C C C C C C

COO–

CH2

C

CH 2

COO–

COO– HO

CoA

C

S

O

CH +

Citrate

1

H2O

Citrate

synthetase

2A


30

Acetyl CoA

CoA—SH

C C

C C C C C C

C C C C C C

COO–

CH2

C

CH 2

COO–

COO– HO

COO–

CH2

HC

CH HO

COO–

COO–

CoA

C

S

O

CH +

Citrate

Isocitrate

Aconitase

1

2B

H2O

Citrate

synthetase

2A


31

Acetyl CoA

CoA—SH

NAD+

NADH

C C

C C C C C C

C C C C C C C C C C C

CO2

COO–

CH2

C

CH 2

COO–

COO– HO

COO–

CH2

HC

CH HO

COO–

COO–

COO–

CH2

CH2

C

COO–

O

+

CoA

C

S

O

CH +

Citrate

Isocitrate α-Ketoglutarate

Aconitase

1

2B

3

H2O

Citrate

synthetase

2A

Isocitrate

dehydro-

genase


32

Acetyl CoA

CoA—SH

NAD+

NAD+

NADH

NADH

CoA—SH

C C

C C C C C C

C C C C C C C C C C C CO2

CO2

C C C C

COO–

CH2

C

CH 2

COO–

COO– HO

COO–

CH2

HC

CH HO

COO–

COO–

COO–

CH2

CH2

C

COO–

O

+

COO–

CH2

CH2

C

S

O

CoA

+

CoA

C

S

O

CH +

Citrate


Succinyl-CoA

Aconitase

1

2B

3 4

H2O

Citrate

synthetase

2A

Isocitrate

dehydro-

genase

α-Ketoglutarate

dehydrogenase


33

C C C C

ATP Acetyl CoA

CoA—SH

GTP

ADP

GDP + Pi

CoA—SH

NAD+

NAD+

NADH

NADH

CoA—SH

C C

C C C C C C


CO2

C C C C

COO–

CH2

C

CH 2

COO–

COO– HO

COO–

CH2

HC

CH HO

COO–

COO–

COO–

CH2

CH2

C

COO–

O

+

COO–

CH2

CH2

C

S

O

CoA

+

CoA

C

S

O

CH +

Citrate


Succinyl-CoA

Aconitase

1

2B

3 4

H2O

Citrate

synthetase Succinyl-CoA

synthetase

2A

Isocitrate

dehydro-

genase

α-Ketoglutarate

dehydrogenase

COO–

COO–

CH2

CH2

Succinate

5


34

ATP Acetyl CoA

CoA—SH

GTP

ADP

GDP + Pi

CoA—SH

NAD+

NAD+

NADH

NADH

CoA—SH

C C

C C C C C C


CO2

C C C C

C C C C

COO–

CH2

C

CH 2

COO–

COO– HO

COO–

CH2

HC

CH HO

COO–

COO–

COO–

CH2

CH2

C

COO–

O

+

COO–

CH2

CH2

C

S

O

CoA

+

COO–

COO–

CH

HC

CoA

C

S

O

CH +

Citrate


Succinyl-CoA

Aconitase

Fumarase

Fumarate

1

2B

3 4

7

H2O

Citrate


synthetase

2A

Isocitrate

dehydro-

genase

α-Ketoglutarate

dehydrogenase

FAD FADH2

C C C C

COO–

COO–

CH2

CH2

Succinate

Succinate

dehydrogenase

6

5


35

C C C C

ATP Acetyl CoA

CoA—SH

GTP

ADP

GDP + Pi

CoA—SH

NAD+

NAD+

NADH

NADH

CoA—SH

C C

C C C C C C


CO2

C C C C

C C C C C C C C

COO–

CH2

C

CH 2

COO–

COO– HO

COO–

CH2

HC

CH HO

COO–

COO–

COO–

CH2

CH2

C

COO–

O

+

COO–

CH2

CH2

C

S

O

CoA

+

COO–

COO–

CH

HC

COO–

COO–

CH HO

CH2

CoA

C

S

O

CH +

Citrate


Succinyl-CoA

Aconitase

Fumarase

Fumarate Malate

1

2B

3 4

7 8

H2O

Citrate


synthetase

H2O

2A

Isocitrate

dehydro-

genase

α-Ketoglutarate

dehydrogenase

FAD FADH2

COO–

COO–

CH2

CH2

Succinate

Succinate

dehydrogenase

6

5


36

ATP Acetyl CoA

CoA—SH

GTP

ADP

GDP + Pi

CoA—SH

Citric acid cycle

NAD+

NADH

NAD+

NAD+

NADH

NADH

CoA—SH

C C

C C C C C C


CO2

C C C C

C C C C C C C C

C C C C

COO–

CH2

C

CH 2

COO–

COO– HO

COO–

CH2

HC

CH HO

COO–

COO–

COO–

CH2

CH2

C

COO–

O

+

COO–

CH2

CH2

C

S

O

CoA

+

COO–

COO–

CH

HC

COO–

COO–

CH HO

CH2

COO–

COO–

C O

CH2

CoA

C

S

O

CH +

Citrate


Succinyl-CoA

Aconitase

Fumarase

Fumarate Malate

Oxaloacetate

1

2B

3 4

7 8

H2O

Citrate


synthetase

H2O

2A

Isocitrate

dehydro-

genase

α-Ketoglutarate

dehydrogenase

Malate

dehydro-

genase

FAD FADH2

C C C C

COO–

COO–

CH2

CH2

Succinate

Succinate

dehydrogenase

6

5


37

Stage 4: Oxidative phosphorylation

High energy electrons removed from

NADH and FADH2 to make ATP

Typically requires oxygen

Oxidative process involves electron

transport chain

Phosphorylation occurs by ATP synthase

38

Oxidation: ETC

Electron transport chains (ETC)

Group of protein complexes and small organic

molecules embedded in the inner mitochondrial

membrane

Can accept and donate electrons in a linear

manner in a series of redox reactions

Movement of electrons generates H+

electrochemical gradient/ proton-motive force

Excess of positive charges outside of matrix

39


NAD+

c

I

III

II

IV

H2O

Q

Matrix

+

NADH dehydrogenase

Ubiquinone

Cytochrome b-c1

Cytochrome c

Cytochrome oxidase

ATP synthase

Succinate

reductase

Inner mitochondrial

membrane

ATP

synthesis

Electron

transport

chain

Intermembrane

space

movement

e– movement

KE Y

H+

NADH

FAD + 2

H+

H+ H+

H+

H+

H+

H+

H+

H+

H+

H+ H+

H+

H+

H+

H+

H+

H- -

FADH2

ADP + Pi

H+

2 H+ + ½ O2

ATP

Matrix

Intermembrane

space

Phosphorylation: ATP synthase

Lipid bilayer of inner mitochondrial

membrane relatively impermeable to H+

Can only pass through ATP synthase

Harnesses free energy release to

synthesize ATP from ADP

Chemiosmosis- chemical synthesis of ATP

as a result of pushing H + across a

membrane

40

41

NADH oxidation and ATP

synthesis

Oxidation of NADH results in

electrochemical gradient used to

synthesize ATP

30-34 ATP molecules per glucose

molecule broken down into CO2 and H2O

Rarely achieve maximal amount

NADH used in anabolic pathways

H+ gradient used for other purposes

42

ATP synthase

Enzyme harnesses free energy as H+ flow

through membrane embedded region

Energy conversion- H+ electrochemical gradient

or proton motive force converted to chemical

bond energy in ATP

Racker and Stoeckenius confirmed ATP uses an

H+ electrochemical gradient

Rotary machine that makes ATP as it spins

43

ATP synthase

Vesicle

Bacteriorhodopsin

(light-driven H+ pump)

ADP

Pi

No H+ gradient

Light rays

H+ gradient

ATP


44

H+

a

b

c c

c

H+

Matrix

Intermembrane

space


ATP ADP + Pi

45

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Yoshida and Kinosita deomonstrate that the γ

subunit of the ATP synthase spins

Masasuke Yoshida, Kazuhiko Kinosita, and

colleagues set out to experimentally visualize the

rotary nature of the ATP synthase

Released membrane embedded portion and

adhered it to a slide

Visualize γ subunit using fluorescence

Added ATP to make reaction run backward

Rotated counterclockwise to hydrolyze ATP

Rotate clockwise to synthesize ATP


Experimental level Conceptual level

No ATP added

ATP Rotation

ATP added

No rotation observed.

Rotation was observed as shown below. This is a time-lapse view of the rotation in action.

Control:

Linker proteins

33 complex

Slide

+ ATP: counterclockwise

rotation Fluorescence

microscope

Fluorescent

actin

filament

ATP ATP

Add linker proteins

and fluorescent

actin filaments.

Add purified

complex.

Cancer cells usually favor

glycolysis

Many disease associated with alterations in

carbohydrate metabolism

Warburg effect- cancer cells preferentially use

glycolysis while decreasing oxidative

phosphorylation

Used to diagnose cancers in PET scans

Glycolytic enzymes overexpressed in 80% of all

types of cancers

Caused by genetic and environmental factors-

mutations and low oxygen

50

Other organic molecules

Focus on glucose but other carbohydrates,

proteins and fats also used for energy

Enter into glycolysis or citric acid cycle at

different points

Utilizing the same pathways for breakdown

increases efficiency

Metabolism can also be used to make other

molecules (anabolism)

51


Proteins Carbohydrates Fats

Sugars

Pyruvate

Acetyl CoA

Amino

acids

Glycolysis:

Glucose

Glyceraldehyde-

3-phosphate

Citric

acid

cycle

Oxidative

phosphorylation

Glycerol Fatty

acids

© The McGraw-Hill Companies, Inc./Ernie Friedlander/Cole Group/Getty Images

52

Anaerobic metabolism

For environments that lack oxygen or

during oxygen deficits

2 strategies

Use substance other than O2 as final electron

acceptor in electron transport chain

Produce ATP only via substrate-level

phosphorylation

Other acceptors

E. coli uses nitrate

(NO3-) under

anaerobic conditions

Makes ATP via

chemiosmosis even

under aerobic

conditions

53


NADH

NAD+ +

Ubiquinone

Cytochrome b

Nitrate reductase

ATP

ATP synthase

Cytoplasm

NADH dehydrogenase

H+

Extracellular

fluid

+ Pi ADP

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

NO2– + H2O

NO3– + 2 H+

H+ movement

KE Y

e– movement

Fermentation

Many organisms can only use O2 as final

electron acceptor

Make ATP via glycolysis only

Need to regenerate NAD+ to keep

glycolysis running

Muscle cells produce lactate

Yeast make ethanol

Produces far less ATP 54

55


(a) Production of lactic acid (b) Production of ethanol

2 lactate (secreted from the cell)

2 H1

2 NAD+ + 2 H+ 2 NADH

2 ATP

2 ethanol (secreted from the cell) 2 acetaldehyde

2 H+

2 pyruvate

2 NAD+ + 2 H+ 2 NADH

Glycolysis Glucose

2 pyruvate

2 ATP

Glycolysis Glucose

O

O C

O—

C

CH3

O

H OH C

C

O—

CH3

+ 2 Pi 2 ADP

O

O C

O—

C

CH3

2 CO2

H OH C

H

CH3

O C

H

CH3

(weights): © Bill Aron/Photo Edit; (wine barrels): © Jeff Greenberg/The Image Works

+ 2 Pi 2 ADP

56

Secondary Metabolism

Primary metabolism- essential for cell structure and function

Secondary metabolism- synthesis of secondary metabolites that are not necessary for cell structure and growth

Secondary metabolites unique to a species or group

Roles in defense, attraction, protection, competition

57

4 categories

Phenolics

Antioxidants with intense flavors and smells

Alkaloids

Bitter-tasting molecules for defense

Terpenoids

Intense smells and colors

Polyketides

Chemical weapons

chapter 7 lecture slides - pbworksacademygenbioii.pbworks.com/f/chapter7brooker.pdf · 2 cellular...

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