Cellular Respiration and Fermentation - Walsingham …spa.walsingham.org/classdocuments/30125/AP Bio 07_Lec_Pre.pdf · During cellular respiration, the fuel (such as glucose) is oxidized,

CAMPBELL BIOLOGY IN FOCUS

© 2014 Pearson Education, Inc.

Urry • Cain • Wasserman • Minorsky • Jackson • Reece

Lecture Presentations by

Kathleen Fitzpatrick and Nicole Tunbridge

7 Cellular

Respiration

and Fermentation

http://www.mediaresource.org/instruct.htm

Overview: Life Is Work

Living cells require energy from outside sources

Some animals, such as the giraffe, obtain energy by

eating plants, and some animals feed on other

organisms that eat plants



Figure 7.1

Energy flows into an ecosystem as sunlight and

leaves as heat

Photosynthesis generates O2 and organic molecules,

which are used as fuel for cellular respiration

Cells use chemical energy stored in organic

molecules to regenerate ATP, which powers work


Video: Carbon Cycle


Figure 7.2

Light energy

ECOSYSTEM

Photosynthesis in chloroplasts

CO2 H2O

Cellular respiration in mitochondria

Organic molecules

O2

ATP ATP powers most cellular work

Heat energy

Concept 7.1: Catabolic pathways yield energy by oxidizing organic fuels

Several processes are central to cellular respiration

and related pathways


Catabolic Pathways and Production of ATP

The breakdown of organic molecules is exergonic

Fermentation is a partial degradation of sugars that occurs without O2

Aerobic respiration consumes organic molecules and O2 and yields ATP

Anaerobic respiration is similar to aerobic respiration but consumes compounds other than O2


Cellular respiration includes both aerobic and

anaerobic respiration but is often used to refer to

aerobic respiration

Although carbohydrates, fats, and proteins are all

consumed as fuel, it is helpful to trace cellular

respiration with the sugar glucose

C6H12O6 6 O2 6 CO2 6 H2O Energy (ATP heat)


Redox Reactions: Oxidation and Reduction

The transfer of electrons during chemical reactions

releases energy stored in organic molecules

This released energy is ultimately used to synthesize

ATP


The Principle of Redox

Chemical reactions that transfer electrons between

reactants are called oxidation-reduction reactions, or

redox reactions

In oxidation, a substance loses electrons, or is oxidized

In reduction, a substance gains electrons, or is

reduced (the amount of positive charge is reduced)



Figure 7.UN01

becomes oxidized (loses electron)

becomes reduced (gains electron)


Figure 7.UN02

becomes oxidized

becomes reduced

The electron donor is called the reducing agent

The electron acceptor is called the oxidizing agent

Some redox reactions do not transfer electrons but change the electron sharing in covalent bonds

An example is the reaction between methane and O2



Figure 7.3

Reactants Products

Methane (reducing

agent)

Oxygen (oxidizing

agent)

Carbon dioxide Water

becomes reduced

becomes oxidized

Redox reactions that move electrons closer to

electronegative atoms, like oxygen, release chemical

energy that can be put to work


Oxidation of Organic Fuel Molecules During Cellular Respiration

During cellular respiration, the fuel (such as glucose)

is oxidized, and O2 is reduced

Organic molecules with an abundance of hydrogen,

like carbohydrates and fats, are excellent fuels

As hydrogen (with its electron) is transferred to

oxygen, energy is released that can be used in ATP

sythesis



Figure 7.UN03

becomes oxidized

becomes reduced

Stepwise Energy Harvest via NAD+ and the Electron Transport Chain

In cellular respiration, glucose and other organic

molecules are broken down in a series of steps

Electrons from organic compounds are usually first

transferred to NAD, a coenzyme

As an electron acceptor, NAD functions as an

oxidizing agent during cellular respiration

Each NADH (the reduced form of NAD) represents

stored energy that is tapped to synthesize ATP



Figure 7.4

NAD

Nicotinamide (oxidized form)

Nicotinamide (reduced form)

Oxidation of NADH

Reduction of NAD

Dehydrogenase NADH

2[H] (from food)

2 e− 2 H

2 e− H

H

H


Figure 7.4a

NAD

Nicotinamide (oxidized form)


Figure 7.4b

Nicotinamide (reduced form)

Oxidation of NADH

Reduction of NAD

Dehydrogenase NADH

2 e− 2 H

2 e− H

H

H 2[H] (from food)


Figure 7.UN04

NADH passes the electrons to the electron

transport chain

Unlike an uncontrolled reaction, the electron

transport chain passes electrons in a series of steps

instead of one explosive reaction

O2 pulls electrons down the chain in an energy-

yielding tumble

The energy yielded is used to regenerate ATP



Figure 7.5

Explosive

release

(a) Uncontrolled reaction (b) Cellular respiration

H2O

Fre

e e

nerg

y,

G

Fre

e e

nerg

y,

G

Controlled release of

energy

H2O

2 H

2 e−

2 H 2 e−

ATP

ATP

ATP

½

½

½ H2 O2

O2

O2

2 H

The Stages of Cellular Respiration: A Preview

Harvesting of energy from glucose has three stages

Glycolysis (breaks down glucose into two molecules

of pyruvate)

Pyruvate oxidation and the citric acid cycle

(completes the breakdown of glucose)

Oxidative phosphorylation (accounts for most of

the ATP synthesis)


Animation: Cellular Respiration

Right click slide / Select play


Figure 7.UN05

Glycolysis (color-coded teal throughout the chapter)

Pyruvate oxidation and the citric acid cycle

(color-coded salmon)

1.

Oxidative phosphorylation: electron transport and

chemiosmosis (color-coded violet)

2.

3.


Figure 7.6-1

Electrons via NADH

Glycolysis

Glucose Pyruvate

CYTOSOL

ATP

Substrate-level

MITOCHONDRION


Figure 7.6-2

Electrons via NADH

Glycolysis

Glucose Pyruvate

Pyruvate oxidation

Acetyl CoA

Citric acid cycle

Electrons via NADH and

FADH2

CYTOSOL

ATP

Substrate-level

ATP

Substrate-level

MITOCHONDRION


Figure 7.6-3

Electrons via NADH

Glycolysis

Glucose Pyruvate

Pyruvate oxidation

Acetyl CoA

Citric acid cycle

Electrons via NADH and

FADH2

Oxidative phosphorylation: electron transport

and chemiosmosis

CYTOSOL

ATP

Substrate-level

ATP

Substrate-level

MITOCHONDRION

ATP

Oxidative

The process that generates most of the ATP is

called oxidative phosphorylation because it is

powered by redox reactions


Oxidative phosphorylation accounts for almost 90%

of the ATP generated by cellular respiration

A smaller amount of ATP is formed in glycolysis and

the citric acid cycle by substrate-level

phosphorylation

For each molecule of glucose degraded to CO2 and

water by respiration, the cell makes up to 32

molecules of ATP



Figure 7.7

Substrate

P

ADP

Product

ATP

Enzyme Enzyme

Concept 7.2: Glycolysis harvests chemical energy by oxidizing glucose to pyruvate

Glycolysis (“sugar splitting”) breaks down glucose

into two molecules of pyruvate

Glycolysis occurs in the cytoplasm and has two

major phases

Energy investment phase

Energy payoff phase

Glycolysis occurs whether or not O2 is present



Figure 7.UN06

Glycolysis Pyruvate

oxidation

Citric acid cycle

Oxidative

phosphorylation

ATP ATP ATP


Figure 7.8

Energy Investment Phase

Energy Payoff Phase

Net

Glucose

Glucose

2 ADP 2 P

4 ADP 4 P

2 NAD 4 e− 4 H

2 NAD 4 e− 4 H

4 ATP formed − 2 ATP used

2 ATP

4 ATP

used

formed

2 NADH 2 H

2 Pyruvate 2 H2O

2 Pyruvate 2 H2O

2 NADH 2 H

2 ATP


Figure 7.9a

Glycolysis: Energy Investment Phase

Glucose ATP

ADP

Glucose 6-phosphate

Phosphogluco-

isomerase

Hexokinase

1 2 3

4

ATP

ADP

Fructose 6-phosphate

Phospho-

fructokinase

Fructose 1,6-bisphosphate

Aldolase

Isomerase

5

Glyceraldehyde 3-phosphate (G3P)

Dihydroxyacetone phosphate (DHAP)


Figure 7.9aa-1


Glucose


Figure 7.9aa-2


Glucose Glucose

6-phosphate

ADP

ATP

Hexokinase

1


Figure 7.9aa-3


Glucose Glucose

6-phosphate

ADP

ATP

Hexokinase

1


Phosphogluco-

isomerase

2


Figure 7.9ab-1




Figure 7.9ab-2



Phospho-

fructokinase

3


ATP

ADP


Figure 7.9ab-3



Phospho-

fructokinase

3

Aldolase

Isomerase

4

5



ATP

ADP



Figure 7.9b

Glycolysis: Energy Payoff Phase

2 NAD Glyceraldehyde

3-phosphate (G3P)

Triose

phosphate

dehydrogenase

6

2 H

2 NADH

2

2 P i

1,3-Bisphospho- glycerate

3-Phospho- glycerate


Phosphoenol-

pyruvate (PEP)

Pyruvate

Phospho-

glycerokinase

Phospho-

glyceromutase

Enolase Pyruvate

kinase

2 ADP 2 2 2 2 2 ADP

2 ATP 2 H2O

2 ATP

9 10 8 7


Figure 7.9ba-1

Isomerase

4




Aldolase 5


Figure 7.9ba-2

Isomerase




2 NAD

Triose phosphate

dehydrogenase

2 H

2 NADH

2


2

Aldolase

P i

5 6

4


Figure 7.9ba-3

Isomerase




2 NAD

Triose phosphate

dehydrogenase

2 H

2 NADH

2



Phospho- glycerokinase

2 ADP

2 ATP

2

Aldolase

P i

2

5 7 6

4


Figure 7.9bb-1



2


Figure 7.9bb-2

8 3-Phospho- glycerate


Phospho- glyceromutase

2 2 2

2 H2O


Phosphoenol- pyruvate (PEP)

Enolase

9


Figure 7.9bb-3



2 ATP

Phospho- glyceromutase

2 2 2 2 2 ADP

2 H2O


Phosphoenol- pyruvate (PEP)

Pyruvate

Enolase Pyruvate kinase

9 10 8

Concept 7.3: After pyruvate is oxidized, the citric acid cycle completes the energy-yielding oxidation of organic molecules

In the presence of O2, pyruvate enters the

mitochondrion (in eukaryotic cells), where the

oxidation of glucose is completed

Before the citric acid cycle can begin, pyruvate must

be converted to acetyl coenzyme A (acetyl CoA),

which links glycolysis to the citric acid cycle



Figure 7.UN07

Glycolysis Pyruvate

oxidation

Citric acid cycle

Oxidative

phosphorylation

ATP ATP ATP


Figure 7.10

CYTOSOL Pyruvate (from glycolysis, 2 molecules per glucose)

CO2

CoA NAD

NADH

MITOCHONDRION CoA

CoA

Acetyl CoA H

Citric acid cycle

FADH2

FAD

ADP P i

ATP

NADH

3 NAD

3

3 H

2 CO2


Figure 7.10a

CYTOSOL Pyruvate (from glycolysis, 2 molecules per glucose)

CO2

CoA NAD

NADH

MITOCHONDRION CoA

Acetyl CoA H


Figure 7.10b

CoA

Citric

acid

cycle FADH2

FAD

ADP P i

ATP

NADH

3 NAD

3

3 H

2 CO2

CoA

Acetyl CoA

The citric acid cycle, also called the Krebs cycle,

completes the breakdown of pyruvate to CO2

The cycle oxidizes organic fuel derived from

pyruvate, generating 1 ATP, 3 NADH, and 1 FADH2

per turn



Figure 7.UN08

Glycolysis Pyruvate

oxidation

Oxidative

phosphorylation

ATP ATP ATP

Citric acid cycle


Figure 7.11-1

Acetyl CoA

Oxaloacetate

CoA-SH

Citrate

H2O

Isocitrate

Citric acid cycle

2

1


Figure 7.11-2

Acetyl CoA

Oxaloacetate

Citrate

H2O

Isocitrate

NADH

NAD

H

CO2

-Ketoglutarate

Citric acid cycle

3

1

CoA-SH

2


Figure 7.11-3

Acetyl CoA

Oxaloacetate

Citrate

H2O

Isocitrate

NADH

NAD

H

CO2

-Ketoglutarate

Citric acid cycle

CoA-SH

CO2 NAD

NADH

H Succinyl CoA

4

1

3

CoA-SH

2


Figure 7.11-4

Acetyl CoA

Oxaloacetate

Citrate

H2O

Isocitrate

NADH

NAD

H

CO2

-Ketoglutarate

Citric acid cycle

CoA-SH

CO2 NAD

NADH

H

ATP formation

Succinyl CoA

ADP

GDP GTP

P i

ATP

Succinate

5

4

1

CoA-SH

3

CoA-SH

2


Figure 7.11-5

Malate

Succinate

FAD

FADH2

Fumarate

H2O 7

6

Acetyl CoA

Oxaloacetate

Citrate

H2O

Isocitrate

NADH

NAD

H

CO2

-Ketoglutarate

Citric acid cycle

CoA-SH

CO2 NAD

NADH

H

ATP formation

Succinyl CoA

ADP

GDP GTP

P i

ATP

5

4

1

CoA-SH

3

CoA-SH

2


Figure 7.11-6

NADH

NAD

H

8

Malate

Succinate

FAD

FADH2

Fumarate

H2O 7

6

Acetyl CoA

Oxaloacetate

Citrate

H2O

Isocitrate

NADH

NAD

H

CO2

-Ketoglutarate

Citric acid cycle

CoA-SH

CO2 NAD

NADH

H

ATP formation

Succinyl CoA

ADP

GDP GTP

P i

ATP

5

4

1

CoA-SH

3

CoA-SH

2


Figure 7.11a

CoA-SH

Acetyl CoA

Start: Acetyl CoA adds its two-carbon group to oxaloacetate, producing citrate; this is a highly exergonic reaction.

Oxaloacetate

Citrate

Isocitrate

H2O 1

2


Figure 7.11b

Isocitrate Redox reaction: Isocitrate is oxidized; NAD is reduced.

Redox reaction: After CO2 release, the resulting four-carbon molecule is oxidized (reducing NAD), then made reactive by addition of CoA.

CO2 release

CO2 release

-Ketoglutarate

Succinyl CoA

NAD

NADH

H

CO2

CO2

CoA-SH

NAD

NADH

H

3

4


Figure 7.11c

CoA-SH

Redox reaction: Succinate is oxidized; FAD is reduced.

Fumarate

Succinate

Succinyl CoA

ATP formation

ATP

ADP

GDP GTP

FAD

FADH2

P i

5

6


Figure 7.11d

Redox reaction: Malate is oxidized; NAD is reduced.

Fumarate

Malate

Oxaloacetate

H2O

NAD

H

NADH

7

8

The citric acid cycle has eight steps, each catalyzed

by a specific enzyme

The acetyl group of acetyl CoA joins the cycle by

combining with oxaloacetate, forming citrate

The next seven steps decompose the citrate back to

oxaloacetate, making the process a cycle

The NADH and FADH2 produced by the cycle relay

electrons extracted from food to the electron

transport chain


Concept 7.4: During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis

Following glycolysis and the citric acid cycle, NADH

and FADH2 account for most of the energy extracted

from food

These two electron carriers donate electrons to the

electron transport chain, which powers ATP synthesis

via oxidative phosphorylation


The Pathway of Electron Transport

The electron transport chain is in the inner

membrane (cristae) of the mitochondrion

Most of the chain’s components are proteins, which

exist in multiprotein complexes

The carriers alternate reduced and oxidized states as

they accept and donate electrons

Electrons drop in free energy as they go down the

chain and are finally passed to O2, forming H2O



Figure 7.UN09

Glycolysis Pyruvate

oxidation

Citric acid cycle

Oxidative

phosphorylation:

electron transport

and chemiosmosis

ATP ATP ATP


Figure 7.12

Multiprotein complexes

(originally from NADH or FADH2)

Fre

e e

nerg

y (

G)

rela

tive t

o O

2 (

kcal/m

ol)

50

40

30

20

10

0

NADH

NAD

FADH2

FAD

2

2

e−

e−

FMN

Fe•S Fe•S

Q

I II

III Cyt b

Cyt c1

Fe•S

Cyt c IV

Cyt a

Cyt a3

2 e−

O2 2 H ½

H2O


Figure 7.12a

Multiprotein complexes

Fre

e e

nerg

y (

G)

rela

tive t

o O

2 (

kcal/m

ol)

50

40

30

20

10

NADH

NAD

FADH2

FAD

2

2

e−

e−

FMN

Fe•S Fe•S

Q

I

II

III Cyt b

Cyt c1

Fe•S

Cyt c IV

Cyt a

Cyt a3

2 e−


Figure 7.12b

30

20

10

0

Cyt c1

Cyt c IV

Cyt a

Cyt a3

2 e−

Fre

e e

ne

rgy (

G)

rela

tive t

o O

2 (

kcal/

mo

l)

(originally from NADH or FADH2)

2 H ½ O2

H2O

Electrons are transferred from NADH or FADH2 to

the electron transport chain

Electrons are passed through a number of proteins

including cytochromes (each with an iron atom)

to O2

The electron transport chain generates no ATP

directly

It breaks the large free-energy drop from food to O2

into smaller steps that release energy in manageable

amounts


Chemiosmosis: The Energy-Coupling Mechanism

Electron transfer in the electron transport chain

causes proteins to pump H from the mitochondrial

matrix to the intermembrane space

H then moves back across the membrane, passing

through the protein complex, ATP synthase

ATP synthase uses the exergonic flow of H to drive

phosphorylation of ATP

This is an example of chemiosmosis, the use of

energy in a H gradient to drive cellular work


Video: ATP Synthase 3-D Side View

Video: ATP Synthase 3-D Top View


Figure 7.13

INTERMEMBRANE SPACE

MITOCHONDRIAL MATRIX

Rotor

Internal rod

Catalytic knob

Stator H

ATP

ADP

P i

The energy stored in a H gradient across a

membrane couples the redox reactions of the electron

transport chain to ATP synthesis

The H gradient is referred to as a proton-motive

force, emphasizing its capacity to do work



Figure 7.UN09

Glycolysis Pyruvate

oxidation

Citric acid cycle

Oxidative

phosphorylation:

electron transport

and chemiosmosis

ATP ATP ATP


Figure 7.14

Protein complex of electron carriers

H

H H

H

Q

I

II

III

FADH2 FAD

NAD NADH

(carrying electrons

from food)

Electron transport chain

Oxidative phosphorylation

Chemiosmosis

ATP

synthase

H

ADP ATP P i

H2O 2 H ½ O2

IV

Cyt c

1 2


Figure 7.14a


H

Q

I

II

III

FADH2 FAD

NAD NADH

(carrying electrons

from food)

Electron transport chain

H2O 2 H ½ O2

Cyt c

1

IV

H H


Figure 7.14b

ATP

synthase

Chemiosmosis 2

H

H

ADP P i

ATP

An Accounting of ATP Production by Cellular Respiration

During cellular respiration, most energy flows in the

following sequence:

glucose NADH electron 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

There are several reasons why the number of ATP

molecules is not known exactly



Figure 7.15

Electron shuttles span membrane

CYTOSOL 2 NADH

2 NADH

2 FADH2

or

2 NADH

Glycolysis

Glucose 2 Pyruvate

Pyruvate oxidation

2 Acetyl CoA

Citric acid cycle

6 NADH 2 FADH2


and chemiosmosis

about 26 or 28 ATP 2 ATP 2 ATP

About 30 or 32 ATP

Maximum per glucose:

MITOCHONDRION


Figure 7.15a

Electron shuttles span membrane

2 NADH

2 FADH2

or

2 NADH

Glycolysis

Glucose 2 Pyruvate

2 ATP


Figure 7.15b

2 NADH 6 NADH 2 FADH2

Citric acid cycle

Pyruvate oxidation

2 Acetyl CoA

2 ATP


Figure 7.15c

2 NADH

2 NADH 6 NADH 2 FADH2

2 FADH2

or


and chemiosmosis

about 26 or 28 ATP


Figure 7.15d

Maximum per glucose: About

30 or 32 ATP

Concept 7.5: Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen

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


Anaerobic respiration uses an electron transport

chain with a final electron acceptor other than O2, for

example, sulfate

Fermentation uses substrate-level phosphorylation

instead of an electron transport chain to generate

ATP


Types of Fermentation

Fermentation consists of glycolysis plus reactions

that regenerate NAD, which can be reused by

glycolysis

Two common types are alcohol fermentation and

lactic acid fermentation


In alcohol fermentation, pyruvate is converted to

ethanol in two steps

The first step releases CO2 from pyruvate, and the

second step reduces acetaldehyde to ethanol

Alcohol fermentation by yeast is used in brewing,

winemaking, and baking


Animation: Fermentation Overview

Right click slide / Select play


Figure 7.16

2 ADP 2 2 ATP P i

Glucose Glycolysis

2 Pyruvate

2 CO2 2 NADH

2 H

2 NAD

2 Ethanol

(a) Alcohol fermentation

2 Acetaldehyde

(b) Lactic acid fermentation

2 Lactate

2 NADH

2 H

2 NAD

2 Pyruvate

Glycolysis

2 ATP 2 ADP 2 P i

Glucose


Figure 7.16a

2 ADP 2 2 ATP P i

Glucose Glycolysis

2 Pyruvate

2 CO2 2 NADH

2 H

2 NAD

2 Ethanol

(a) Alcohol fermentation

2 Acetaldehyde


Figure 7.16b

2 ADP 2 2 ATP P i

Glucose Glycolysis

2 Pyruvate

2 NADH

2 H

2 NAD

(b) Lactic acid fermentation

2 Lactate

In lactic acid fermentation, pyruvate is reduced by

NADH, forming lactate as an end product, with no

release of CO2

Lactic acid fermentation 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


Comparing Fermentation with Anaerobic and Aerobic Respiration

All use glycolysis (net ATP 2) to oxidize glucose and harvest chemical energy of food

In all three, NAD is the oxidizing agent that accepts electrons during glycolysis

The processes have different final electron acceptors: an organic molecule (such as pyruvate or acetaldehyde) in fermentation and O2 in cellular respiration

Cellular respiration produces 32 ATP per glucose molecule; fermentation produces 2 ATP per glucose molecule


Obligate anaerobes carry out only fermentation or

anaerobic respiration and cannot survive in the

presence of O2

Yeast and many bacteria are facultative anaerobes,

meaning that they can survive using either

fermentation or cellular respiration

In a facultative anaerobe, pyruvate is a fork in the

metabolic road that leads to two alternative catabolic

routes



Figure 7.17 Glucose

CYTOSOL Glycolysis

Pyruvate

O2 present:

Aerobic cellular

respiration

No O2 present:

Fermentation

Ethanol, lactate, or

other products

Acetyl CoA

Citric acid cycle

MITOCHONDRION

The Evolutionary Significance of Glycolysis

Ancient prokaryotes are thought to have used

glycolysis long before there was oxygen in the

atmosphere

Very little O2 was available in the atmosphere until

about 2.7 billion years ago, so early prokaryotes

likely used only glycolysis to generate ATP

Glycolysis is a very ancient process


Concept 7.6: Glycolysis and the citric acid cycle connect to many other metabolic pathways

Gycolysis and the citric acid cycle are major

intersections to various catabolic and anabolic

pathways


The Versatility of Catabolism

Catabolic pathways funnel electrons from many kinds

of organic molecules into cellular respiration

Glycolysis accepts a wide range of carbohydrates

Proteins must be digested to amino acids and amino

groups must be removed before amino acids can

feed glycolysis or the citric acid cycle


Fats are digested to glycerol (used in glycolysis) and

fatty acids

Fatty acids are broken down by beta oxidation and

yield acetyl CoA

An oxidized gram of fat produces more than twice as

much ATP as an oxidized gram of carbohydrate



Figure 7.18-1

Proteins

Amino acids

Carbohydrates

Sugars

Fats

Glycerol Fatty acids


Figure 7.18-2

Proteins

Amino acids

Carbohydrates

Sugars

Glucose

Glycolysis

Glyceraldehyde 3-

Pyruvate

P

NH3

Fats



Figure 7.18-3

Proteins

Amino acids

Carbohydrates

Sugars

Glucose

Glycolysis

Glyceraldehyde 3-

Pyruvate

P

Acetyl CoA

NH3

Fats



Figure 7.18-4

Proteins

Amino acids

Carbohydrates

Sugars

Glucose

Glycolysis

Glyceraldehyde 3-

Pyruvate

P

Acetyl CoA

Citric acid cycle

NH3

Fats



Figure 7.18-5

Proteins

Amino acids

Carbohydrates

Sugars

Glucose

Glycolysis

Glyceraldehyde 3-

Pyruvate

P

Acetyl CoA

Citric acid cycle

NH3

Fats


Oxidative phosphorylation

Biosynthesis (Anabolic Pathways)

The body uses small molecules to build other

substances

Some of these small molecules come directly from

food; others can be produced during glycolysis or

the citric acid cycle



Figure 7.UN10a


Figure 7.UN10b


Figure 7.UN11

Inputs

Glucose

Glycolysis

2 Pyruvate 2

Outputs

ATP NADH 2


Figure 7.UN12

Inputs

2 Pyruvate 2 Acetyl CoA

2 Oxaloacetate Citric

acid

cycle

Outputs

ATP

CO2

2

6 2

8 NADH

FADH2


Figure 7.UN13a


INTERMEMBRANE SPACE

MITOCHONDRIAL MATRIX (carrying electrons from food)

NADH NAD

FADH2 FAD

Cyt c

Q

I

II

III

IV

2 H ½O2 H2O

H

H H


Figure 7.UN13b

INTER- MEMBRANE SPACE

MITO- CHONDRIAL MATRIX

ATP synthase

ATP ADP H

H

P i


Figure 7.UN14

Time

pH

dif

fere

nc

e

acro

ss m

em

bra

ne

Documents

Cellular Respiration and Fermentation - Walsingham …spa.walsingham.org/classdocuments/30125/AP Bio 07_Lec_Pre.pdf · During cellular respiration, the fuel (such as glucose) is oxidized,