Chapter 15 Cellular Respiration 6

7/30/2019 Chapter 15 Cellular Respiration 6

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15.1: Types of respiration: aerobic and

anaerobic

15.2 : Aerobic respiration

15.3 : Anaerobic respiration :

fermentation and application

Electrons

carried

via NADH

Electrons carried

via NADH and

FADH2

Citric

acid

cycle

Pyruvate

oxidation

Acetyl CoA

Glycolysis

Glucose Pyruvate

Oxidative

phosphorylation:

electron transport

and

chemiosmosis

CYTOSOL MITOCHONDRION

ATP ATP ATP

Substrate-level

phosphorylation

Substrate-level

phosphorylation

Oxidative

phosphorylation

A membrane-bound enzyme in chloroplast and

mitochondria that uses the energy of protons

flowing through it to synthesize ATP.

What is ATP Synthase?

a) Explain complete oxidation of one molecule of

glucose in active cells.

b) Explain what is meant by fermentation.

c) State the importance of fermentation in industry

i) Bakery

ii) Wine, beverage and alcohol production

Iii) Dairy industry cheese and yoghurt

iv) Local examples could be introduced
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An Accounting of ATP Production

by Cellular Respiration

During cellular respiration, most energy flows

in this sequence:

GlucoseNADHelectron transport

chain proton-motive force ATP

About 34% of the energy in a glucose molecule

is transferred to ATP during cellular respiration

Making about 32 ATP.

2011 Pearson Education, Inc.

Cellular Respiration Produces

ATP

MITOCHONDRION2 NADH

2 NADH 2 NADH 6 NADH

2 FADH2

2 FADH2

or

2 ATP2 ATP about 26 or 28 ATP

Glycolysis

Glucose 2 Pyruvate

Pyruvate oxidation

2 Acetyl CoACitricacidcycle

Oxidativephosphorylation:electron transport

andchemiosmosis

CYTOSOL

Maximum per glucose:About

30 or 32 ATP

ATP Production

by Cellular RespirationMalate shuttle

Glycerol shuttle

Glucose

PyruvatePyruvate

2 ATP/glycolysis

(Substrate Level)

2 NADH

Acetyl - CoA

1 NADH

1 ATP/cycle

(Substrate level)

3 NADH

1 FADH2

x 3 ATP/NADH =

x 3 ATP/NADH = 3 ATP

x 3/NADH = 9 ATP/cycle

x 2/FADH = 2 ATP/cycle

Malate shuttle

Oxidation of glucose in

active cells.

Substrate Level Phosphorylation : 3 ATP

Oxidative Phosphorylation : 20 ATP

23 ATP

Glucose

PyruvatePyruvate

2 ATP/glycolysis

(Substrate Level)

2 NADH

Acetyl - CoA

2 NADH

2 ATP

(Substrate level)

6 NADH

2 FADH2

x 3 ATP/NADH =

x 3 ATP/NADH = 6ATP

x 3/NADH = 18 ATP

x 2/FADH = 4 ATP

Malate shuttle

Complete oxidation of glucose

in active cells.

Substrate Level Phosphorylation : 4 ATP

Oxidative Phosphorylation : 34 ATP

38 ATPEnergy Yield per Glucose Molecule


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ATP yield from completeoxidation of glucose

Glycolysis: Glucose into pyruvate 2 ATPGlycolysis: 2 NADH

(Glycerol shuttle = 4 ATP)

(Malate shuttle = 6 ATP) In Active Cells

4 ATPor

6 ATPPyruvate (2) to acetyl CoA yield 2 NADH 6 ATP

Acetyl CoA (2) via Kreb cycle

(2 GTP = 2 ATP)

(6 NADH = 18 ATP)

(2 FADH2 = 4 ATP)

24 ATP

TOTAL 36 or 38 ATP

Where did the glucose come from? Where did the O2 come from?

Where did the CO2 come from?

Where did the H2O come from?

Where did the ATP come from?

What else is produced that is not listed in thisequation?

Why do we breathe?

C6H12O6 6O2 6CO2 6H2O ~36 ATP+ + +

Any Questions??

What is the final electron acceptor in electron

transport chain?

O2

So what happens if O2 unavailable?

ETC backs up

ATP production ceases

cells run out of energy and you die!

Fermentation

and

Anaerobic Respiration

Most cellular respiration requires O2 to produce

ATP.

Without O2, the electron transport chain will cease

to operate.

In that case, glycolysis couples with fermentation

or anaerobic respiration to produce ATP.

Less efficient than aerobic respiration.

Only produce 2 ATP per glucosemolecule.


Glucose

CYTOSOLGlycolysis

Pyruvate

No O2 present:Fermentation

O2

present:

Aerobic cellular

respiration

Ethanol,

lactate, or

other products

Acetyl CoA

MITOCHONDRION

Citric

acid

cycle

A catabolic pathway in which inorganic molecules(Sulfate) other than oxygen accept electrons at the

'down hill' end of electron transport chains.

(Campbell, 9th edition)

other than O2, for example sulfate


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A catabolic process that makes a limited

amount of ATP from glucose (or otherorganic molecules) without an electron

transport chain and that produces a

characteristic end product, such as ethyl

alcohol or lactic acid.

(Campbell, 9th edition)

Lactate/Lactic acid

FermentationAlcoholic

Fermentation


Animation: Fermentation OverviewRight-click slide / select Play

CO2 is released from

the pyruvate,

converting pyruvate

into acetaldehyde.

acetaldehyde reduced

by NADH to Ethanol.

2 ADP 2 P i 2 ATP

GlucoseGlycolysis

2 Pyruvate

2 CO22 NAD

2 NADH

2 Ethanol2 Acetaldehyde

(a) Alcohol fermentation

2 H

Fermentation by yeast

(a fungus) is used in

brewing, wine making

and bakery.


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Pyruvate is reduced to

NADH, forming lactate

as an end product, with

no release of CO2.

By some fungi and

bacteria is used to make

cheese and yogurt

Human muscle cells use

lactic acid fermentation

to generate ATP when

O2 is scarce.

(b) Lactic acid fermentation

2 Lactate

2 Pyruvate

2 NADH

Glucose Glycolysis

2 ADP 2 P i 2 ATP

2 NAD

2 H

2 ADP 2 ATP

Glucose Glycolysis

2 Pyruvate

2 CO222 NADH

2 Ethanol 2 Acetaldehyde

(a) Alcohol fermentation (b) Lactic acid fermentation

2 Lactate

2 Pyruvate

2 NADH

Glucose Glycolysis

2 ATP2 ADP2 Pi

NAD2 H

2 Pi

2NAD2 H

Wine Bakery


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Aerobic Fermentation

Need the O2 as a last electronaccepter

No need O2

Complete glucose oxidation not complete

Produce energy, CO2,and H2O Produce energy, lactic acid

(animal), ethanol + CO2 in

yeast.


More energy per glucose released. Less Energy released

Phosphorylation oxidative occurs,

produce many ATP (38 @36 ATP)

No Phosphorylation oxidative.

Only 2 ATP produce

Involve glycolysis and Krebs cycle Only glycolysis, no Krebs cycle

Reduced products formed :

Water

Reduced products formed:

Reduced organic compounds

(alcohol and lactate)


Mechanism of ATP Synthesis:

Substrate level phosphorylation

Oxidative /Chemiosmosis

Mechanism of ATP Synthesis:

Substrate level phosphorylation

Immediate fate of electron

in NADH :

Transferred to electron transport

chain

Immediate fate of electron

in NADH :

Transferred to organic molecules

Terminal electron acceptor of

electron transport chain is oxygen.

No electron transport chain

Photosynthesis

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Chapter 15 Cellular Respiration 6