Chapter 6 · PDF filePowerPoint Lectures Campbell Biology: Concepts & Connections, Eighth Edition REECE •TAYLOR • SIMON •DICKEY • HOGAN Chapter 6 Lecture by Edward J. Zalisko

PowerPoint Lectures

Campbell Biology: Concepts & Connections, Eighth EditionREECE • TAYLOR • SIMON • DICKEY • HOGAN

Chapter 6

Lecture by Edward J. Zalisko

How Cells Harvest Chemical Energy

© 2015 Pearson Education, Inc.


Figure 6.0-2

Describe how chemical

energy transforms to

kinetic energy

Contrast the three

stages of cellular

respiration

Identify when fermentation occurs Connect

Metabolic Pathways

Chapter 6 Objectives


CELLULAR RESPIRATION:

AEROBIC HARVESTING OF ENERGY


Figure 6.1

Sunlight

energy

ECOSYSTEM

Photosynthesis in

chloroplasts Organic

moleculesCellularrespiration inmitochondria

ATP powers most

cellular work

Heat

energy

CO2 + H2O + O2

ATP


Figure 6.2-0

Lungs

Transported in

bloodstream

Muscle cells carrying out

Breathing

Glucose + O2 ➞ CO2 + H2O + ATP

Cellular Respiration

O2

O2

CO2

CO2


Figure 6.3

Glucose Oxygen Carbon

dioxide

Water

HeatATPH2O6CO26O26C6H12O6


Cellular Respiration

6.4 CONNECTION: The human body uses energy from ATP for all its activities

• Read page 91 and be prepared to discuss



Figure 6.4-1

Activity

Running (8–9 mph)

Dancing (fast)

Bicycling (10 mph)

Swimming (2 mph)

Walking (4 mph)

Walking (3 mph)

Dancing (slow)

Driving a car

Sitting (writing)

kcal consumed per hour

by a 67.5-kg (150-lb) person*

*Not including kcal needed for

body maintenance

979

510

490

408

341

245

204

61

28


Figure 6.4-2



Blood vessel Muscle cell

Mitochondria

Fuel

(glucose)

Oxygen

(O2)


Mitochondrion

Fuel (glucose)

Oxygen

Water

Carbon

dioxide

ATP


Figure 6.5a

Loss of hydrogen atoms

(becomes oxidized)

Gain of hydrogen atoms

(becomes reduced)

(Glucose)

C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATP + Heat


Figure 6.5b

Becomes oxidized+ 2 H

+ 2 HBecomes reduced

NAD+ NADH H+

(carries)

2 electrons)+2 H+ 2


Figure 6.5c

NAD+

H+

NADHEnergy released

and available

for making

2

2

O2

2

H2O

−2

1

ATP


You should now be able to

1. Compare the processes and locations of cellular

respiration and photosynthesis.

2. Explain how breathing and cellular respiration

are related.

© 2015 Pearson

Education, Inc.


STAGES OF CELLULAR

RESPIRATION

Figure 6.0-2



kinetic energy

Contrast the three

stages of cellular

respiration


Metabolic Pathways


6.6 Overview:

• Stage 1: Glycolysis

• Stage 2: Pyruvate oxidation and the citric acid cycle

• Stage 3: Oxidative phosphorylation



Figure 6.6-0

Electrons carried by NADH FADH2

ATP

ATPATP

Glycolysis

Glucose PyruvatePyruvate

OxidationCitric Acid

Cycle

Substrate-level

phosphorylation

Substrate-level

phosphorylation

Oxidative

phosphorylation

OxidativePhosphorylation

(Electron transportand chemiosmosis)

CYTOSOL MITOCHONDRION


Figure 6.7a

Glucose

2 ADP

2 Pyruvate

ATP2

NADH

NAD+

+2 H+

+2

2

2P


Figure 6.7b

Enzyme Enzyme

ADP

Substrate Product

P

P P

ATP

Substrate-level phosphorylation: transfer of a phosphate group

from a substrate to ADP, producing ATP


Figure 6.7c-1-1

Glucose

1

31

2

3

Glucose 6-phosphate

Fructose 6-phosphate

ENERGY

INVESTMENT

PHASEStep

P

ATP

ADP

Steps – Glucose

is energized, using ATP.

ATP

ADP

P


Figure 6.7c-1-2

Glucose

1

31

2

3

4

4

Glucose 6-phosphate

Fructose 6-phosphate

Fructose 1,6-bisphosphate

Glyceraldehyde 3-phosphate

(G3P)

ENERGY

INVESTMENT

PHASEStep

P

ATP

ADP

Step A six-carbon

intermediate splits into

two three-carbon

intermediates.

ATP

ADP

P

PP

P P

Steps – Glucose

is energized, using ATP.


GlucoseATPMitochondrion

Only the carbon skeleton is shown to keep things simple. The first

step is called glycolysis, and it takes place outside the mitochondria.

To begin the process, some energy has to be invested.


Next, the molecule is split in half.


Figure 6.7c-2-1

55 5


(G3P)

P

NAD+ NAD+

NADH NADH

+ H+ + H+

P

PP

P P P P

ENERGY PAYOFF

PHASE

1,3-Bisphosphoglycerate

Step A redox

reaction generates

NADH.


Figure 6.7c-2-2

55 5

6 9

7

8 8

7

6 6

9 9


(G3P)

ATP

ADP

P

ATPATP

ATP

ADP

ADP ADP

H2O H2O

NAD+ NAD+

NADH NADH

+ H+ + H+

P

PP

P P P P

P

P

P

P

P

P

ENERGY PAYOFF

PHASE

1,3-Bisphosphoglycerate

3-Phosphoglycerate

2-Phosphoglycerate

Phosphoenolpyruvate

(PEP)

Pyruvate

Step A redox

reaction generates

NADH.

Steps – ATP

and pyruvate are

produced.


Electron carrier (NADH)

Now, the molecule NAD+, an electron carrier, picks up electrons and hydrogen

atoms from the carbon molecule, becoming NADH. Keep track of the electron

carriers—they play an important role by transporting electrons to reactions in

the mitochondria.


ATP Pyruvic acid

In the final steps of glycolysis, some ATP is produced, but not much—for every

glucose molecule, only two net ATPs are produced outside the mitochondrion.

However, glycolysis has produced pyruvic acid, which still has a lot of energy

available.


Figure 6.8

Pyruvate

NAD+ NADH + H+

1

2

3

Coenzyme ACO2

CoA

Acetyl coenzyme A

The link between glycolysis and the citric acid cycle


Pyruvic acid

Outer mitochondrial

membrane

Inner mitochondrial

membrane

Follow this pyruvic acid molecule into a

mitochondrion to see where most of the

energy is extracted.


Carbon dioxide

As the molecule enters the mitochondrion, one carbon is

removed, forming carbon dioxide as a by-product.



Electrons are stripped, forming NADH.


Acetyl CoACoenzyme A attaches to the 2-

carbon fragment, forming acetyl

CoA.


Figure 6.6-0

Electrons carried by NADH FADH2

ATP

ATPATP

Glycolysis

Glucose PyruvatePyruvate

OxidationCitric Acid

Cycle

Substrate-level

phosphorylation

Substrate-level

phosphorylation

Oxidative

phosphorylation


(Electron transportand chemiosmosis)

CYTOSOL MITOCHONDRION


Figure 6.9a

Citric Acid Cycle

NAD+

NADH

+ 3 H+

CO2

CoA

CoA

Acetyl CoA

2

3

3FADH2

FAD

ATP PADP +


Figure 6.9b-1CoA

CoA

Acetyl CoA

2 carbons enter cycle

Oxaloacetate

Step

Acetyl CoA stokes

the furnace.

1

1

Citric Acid Cycle


Figure 6.9b-2

Citric Acid Cycle

NAD+

NADH

+ H+

CO2

CoA

CoA

Acetyl CoA

ATP

PADP +

CO2

+ H+


Citrate

leaves cycle

Alpha-ketoglutarate

Succinate

Oxaloacetate

leaves cycle

Step

Acetyl CoA stokes

the furnace.

Steps –

NADH, ATP, and CO2

are generated during

redox reactions.

1

1

2

32

3NAD+

NADH


Figure 6.9b-3

Citric Acid Cycle

NAD+

NADH

+ H+

CO2

CoA

CoA

Acetyl CoA

FADH2

FAD

ATP

PADP +

CO2

+ H+

+ H+

NAD+

NADH

H2O


Citrate

leaves cycle

Alpha-ketoglutarate

Succinate

Fumarate

Malate

Oxaloacetate

leaves cycle

Step

Acetyl CoA stokes

the furnace.

Steps –

NADH, ATP, and CO2

are generated during

redox reactions.

Steps –

Further redox reactions

generate FADH2 and

more NADH.

1

1

2

3

5

6

4

6

2

3

4

NAD+

NADH


Coenzyme A

Coenzyme A is removed and the remaining 2-carbon skeleton is

attached to an existing 4-carbon molecule that serves as the starting

point for the citric acid cycle.


Carbon dioxide

The new 6-carbon chain is partially broken down, releasing

carbon dioxide.



Several electrons are captured by electron carriers …


Carbon dioxide

… and more carbon dioxide is released. The carbon dioxide that you

exhale comes from the reactions of cellular respiration.


ATP

Two ATPs are produced by the citric acid cycle for each molecule of

glucose. At this point, only a small number of ATPs have been

produced.


Electron carrier (FADH2)

However, more energy is available in the electrons that are

being transported by electron carriers.


Coenzyme AElectron carrier (NADH)

While the citric acid cycle starts another round, let’s follow an

electron carrier to the next step in the process.

Slide

49 of 37

9-2 The Krebs Cycle and

Electron Transport

Copyright Pearson Prentice Hall

Electron Transport

NADH and FADH2 donate electrons.

Resources/Movies/vaelect1.mov


Slide

50 of 37


Electron Transport


Electron Transport

Oxygen

Slide

51 of 37


Electron Transport


Electron Transport

Water

Slide

52 of 37


Electron Transport


Electron Transport

Energy moves hydrogen ions (H+) across the

membrane.

Slide

53 of 37


Electron Transport


Electron Transport

H+ ions fill intermembrane space



Slide

54 of 37


Electron Transport


Electron Transport

Matrix negatively charged.

Slide

55 of 37


Electron Transport


Electron Transport

ATP

synthase

ATP synthases.

Slide

56 of 37


Electron Transport


Electron Transport

H+ ions cause ATP synthase to spin

ATP

synthase

Channel

Slide

57 of 37


Electron Transport


Electron Transport

Form ATP.

ATP

ATP

synthase

Channel


Figure 6.10a

OUTER MITOCHONDRIAL MEMBRANE

Q

FADH2 FAD

ATPPADP +

H+

NAD+NADH

H2O

O2

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

Cyt c

−2

1+ 2

II

III

I

ATP

synthase

Protein

complex

of electron

carriers

Mobile

electron

carriersIntermem-

brane

space

Inner mito-

chondrial

membrane

Mito-

chondrial

matrix

Electron

flow

Electron Transport Chain

Oxidative Phosphorylation

Chemiosmosis

IV


Figure 6.10b

INTERMEMBRANE SPACE

MITOCHONDRIAL MATRIX

Rotor

Internal

rod

Catalytic

knob

ATP

ADP

P

H+

+

Inner

mitochondrial

membrane

Outer

mitochondrial

membrane

Electron transport chain

Electron carrier

(NADH)

Electrons

Oxygen Electrons

Hydrogen ions

As electrons move along each step of the chain, they give up a bit of energy. The

oxygen you breathe pulls electrons from the transport chain …

Water

and water is formed as a by-product.

Hydrogen ions

Inner

mitochondrial

membrane

Area of high

hydrogen ion

concentration

ATP synthaseATP

Inner

mitochondrial

membrane

Outer

mitochondrial

membrane

The process you’ve just observed, cellular respiration, generates

10 million ATPs per second in just one cell.


Figure 6.0-1

Brown fat generates only heat, not ATP.


Figure 6.11

Lean group Overweight/

obese group

Avera

ge a

cti

vit

y o

f b

row

n f

at

Activity level of brown fat of lean and overweight/obese

participants after cold exposure

6.11 SCIENTIFIC THINKING: Interrupting cellular respiration can have both harmful and beneficial effects

• Page 99


6.11 SCIENTIFIC THINKING: Interrupting cellular respiration can have both harmful and beneficial effects

• Page 99



Figure 6.12

NADH FADH2

CO2

Maximum

per glucose:

+ 2ATP

Glycolysis

Glucose2

Pyruvate

PyruvateOxidation2 Acetyl

CoA

Citric Acid

Cycle

by substrate-level

phosphorylation

by substrate-level

phosphorylation

by oxidative

phosphorylation


(electron transportand chemiosmosis)

CYTOSOLMITOCHONDRION

2NADH2 NADH6 + 2

+ 2ATP

+ about28 ATP

About

32 ATP

O2

H2O



1. Provide the overall chemical equation for

cellular respiration.

2. Explain how the human body uses its daily

supply of ATP.

© 2015 Pearson

Education, Inc.



5. Explain how the energy in a glucose molecule

is released during cellular respiration.

6. Explain how redox reactions are used in


7. Describe the general roles of dehydrogenase,

NADH, and the electron transport chain in


8. Compare the reactants, products, and energy

yield of the three stages of cellular respiration.

© 2015 Pearson

Education, Inc.


FERMENTATION: ANAEROBIC

HARVESTING OF ENERGY

Figure 6.0-2



kinetic energy

Contrast the three

stages of cellular

respiration


Metabolic Pathways


Animation: Fermentation Overview



Figure 6.13aGlucose

2 ADP

2 NADH

2 NAD+

2 ATP2 NADH

2 NAD+

+ 2 P

Gly

co

lys

is

2 Pyruvate

2 Lactate


Figure 6.13bGlucose

2 ADP

2 NADH

2 NAD+

2 ATP 2 NADH

2 NAD+

+ 2 P

Gly

co

lys

is

2 Pyruvate

2 Ethanol

2 CO2



Figure 6.13c-1


Figure 6.13c-2

6.14 EVOLUTION CONNECTION: Glycolysis evolved early in the history of life on Earth

• Read page 102


6.14 EVOLUTION CONNECTION: Glycolysis evolved early in the history of life on Earth

• Read page 102

• Glycolysis occurs in the cytosol and suggests that this process

had an early evolutionary origin. Since atmospheric oxygen was

not available in significant amounts during the early stages of

Earth’s history, and glycolysis does not require oxygen, it is likely

that this chemical pathway was used by the prokaryotes in

existence at that time. We are often focused on the evolution of

large, readily apparent structures such as wings and teeth may

have never considered the evolution of cellular chemistry.



9. Describe the special function of brown fat.

10. Compare the reactants, products, and energy

yield of alcohol and lactic acid fermentation.

11. Distinguish between strict anaerobes and

facultative anaerobes.



CONNECTIONS BETWEEN

METABOLIC PATHWAYS

Figure 6.0-2



kinetic energy

Contrast the three

stages of cellular

respiration


Metabolic Pathways



Figure 6.15-1

Food

Carbohydrates Fats Proteins

Oxidative

Phosphorylation

Sugars Glycerol Fatty acids Amino acids

Amino

groups

Glucose G3P Pyruvate

GlycolysisAcetyl

CoA

Citric

Acid

Cycle

ATP


Figure 6.16-1

Cells, tissues,

organisms

ATP needed

to drive

biosynthesis

CarbohydratesFatsProteins

SugarsGlycerolFatty

acidsAmino acids

Amino

groups

Pyruvate G3P Glucose

Glucose SynthesisAcetyl

CoA

Citric

Acid

Cycle

ATP


Figure 6.16-2


• http://www.hhmi.org/biointeractive/how-body-

uses-fat


ACT question


Figure 6.UN01

Glucose Oxygen Carbon

dioxideWater

HeatATPH2O6CO26O26C6H12O6 +



9. Explain how carbohydrates, fats, and proteins

are used as fuel for cellular respiration.

© 2015 Pearson

Education, Inc.


Figure 6.UN03

Cellular

respiration

glucose and

organic fuels

cellular work

chemiosmosis

H+ gradient

ATP (a)

(b)

(c)

(d)

(e)

(f)

(g)

generates has three stages oxidizes

uses

produce

some

produces

manyenergy for

by a process called

uses

H+ diffuse

through

ATP synthase

pumps H+ to create

uses

to pull

electrons downto

C6H12O6


Figure 6.UN04

Co

lor

inte

nsit

y

a. Time b. Time c. Time

0.30.2

0.1 0.1

0.1

0.20.2

0.3

0.3

Testing your knowledge, question 15

Clicker Questions for

Campbell Biology: Concepts & Connections, Eighth EditionREECE • TAYLOR • SIMON • DICKEY • HOGAN

Chapter 6

Updated by Shannon Datwyler

How Cells Harvest Chemical Energy


Concept Check

Some prokaryotic and all eukaryotic cells use oxygen to harvest

energy from food molecules. In what form is that energy available

to power cell work?

a) heat and light

b) glucose molecules

c) fat molecules

d) ATP molecules


Answer

Some prokaryotic and all eukaryotic cells use oxygen to harvest

energy from food molecules. In what form is that energy available

to power cell work?

a) heat and light

b) glucose molecules

c) fat molecules

d) ATP molecules


Concept Check

Fat molecules store 9 kcal/g. There are about 454 g in a pound of

fat so that means that one pound of fat stores about 4,000 kcal of

energy. Based on the chart of energy consumption, which of the

following would “burn off” around a pound of fat, assuming your

normal activities consumed calories equal to the rate of your

calorie intake?

a) running 7 miles

b) swimming 2 miles

c) walking 27 miles

(3 miles per hour)

d) running 40 miles


Answer

Fat molecules store 9 kcal/g. There are about 454 g in a pound of

fat so that means that one pound of fat stores about 4,000 kcal of

energy. Based on the chart of energy consumption, which of the

following would “burn off” around a pound of fat, assuming your

normal activities consumed calories equal to the rate of your

calorie intake?

a) running 7 miles

b) swimming 2 miles

c) walking 27 miles

(3 miles per hour)

d) running 40 miles


Concept Check

The figure below represents an overview of the different processes

of cellular respiration. Which of the following correctly identifies the

different processes in the correct order?

a) 1. Glycolysis, 2. electron transport chain, 3. citric acid cycle

b) 1. Glycolysis, 2. citric acid cycle, 3. electron transport chain

c) 1. Citric acid cycle, 2. electron transport chain, 3. glycolysis

d) 1. Electron transport chain, 2. glycolysis, 3. citric acid cycle


Answer

The figure to the right represents an overview of the different

processes of cellular respiration. Which of the following correctly

identifies the different processes in the correct order?

a) 1. Glycolysis, 2. electron transport chain, 3. citric acid cycle

b) 1. Glycolysis, 2. citric acid cycle, 3. electron transport chain

c) 1. Citric acid cycle, 2. electron transport chain, 3. glycolysis

d) 1. Electron transport chain, 2. glycolysis, 3. citric acid cycle


Concept Check

The figure represents an overview of the different entry pathways to cellular

respiration when different macromolecules are digested for energy production.

Why are none of the digestive products entering the electron transport chain

directly?

a) The electron transport chain is

too deeply embedded in

the mitochondria.

b) The electron transport chain

only receives electrons carried

by reduced electron carrier

molecules such as NADH.

c) The electron transport chain


by oxidized electron carrier

molecules such as NAD+.

d) The electron transport chain

does not produce ATP.


Answer

The figure represents an overview of the different entry pathways to cellular

respiration when different macromolecules are digested for energy production.

Why are none of the digestive products entering the electron transport chain

directly?

a) The electron transport chain is

too deeply embedded in

the mitochondria.

b) The electron transport chain


by reduced electron carrier

molecules such as NADH.

c) The electron transport chain


by oxidized electron carrier

molecules such as NAD+.

d) The electron transport chain

does not produce ATP.


Biology and Society

Obesity is a serious problem in the United States. This problem is growing the fastest in the under 30 age group. Some link this obesity to fast foods that are high in fat and others link it to the increased consumption of fructose sweetened soft drinks. Do you think that today’s students consume more soft drinks than they should?


Average number soft drinks consumed daily

Age 1971-74 1976-80 1988-94 1999-2000

6-11 4 7 11 15

12-19 6 5 11 15

Disagree Agree

Strongly A B C D E Strongly

Biology and Society

Do you think that your diet is primarily a healthy diet?


Disagree Agree


Biology and Society

There is some preliminary evidence that appears to indicate that a

diet that barely provides enough calories for maintenance could

extend your lifespan. This is called a calorie restricted diet. Would

you consider this type of diet to increase your potential life

span?


Disagree Agree


Biology and Society

One quick indicator of possible obesity is the Body Mass Index.

Here is the formula for the body mass index:

BMI = [Weight in Pounds/(Height in Inches)2] x 703

Calculate your BMI and enter where you fit in the following

table—remember it is anonymous.


BMI Below 18.5 18.5-24.9 25.0-29.9 30.0 and

above

Weight Status A.

Underweight

B.

Normal

C.

OverweightD.

Obese

Documents

Chapter 6 · PDF filePowerPoint Lectures Campbell Biology: Concepts & Connections, Eighth Edition REECE •TAYLOR • SIMON •DICKEY • HOGAN Chapter 6 Lecture by Edward J. Zalisko