1 2 Food like corn can provide energy for the body.

2

Food like corn can provide energy for the body.

3

The sugar in it can also undergo fermentation (發酵 ) to produce an alcohol.

4

The alcohol can be used as a fuel to power vehicles.

5

How does our bodyobtain energy from the food we eat

1

6

How is alcoholproduced from corn by fermentation

2

7

The sugar in corn ismade by photosynthesis. 3What is the relationship between respiration and photosynthesis

8

22.1 Basic concepts of respiration

What is respiration?

9

What is respiration?• when food is burnt, it reacts with oxygen

(oxidation 氧化 ):


glucose

heat

light

O2 CO2 + H2O

10


- one step reaction


- takes place anywhere

- no enzyme involved

- fast and violent reaction

• when food is burnt, it reacts with oxygen (oxidation 氧化 ):

11

the process by which organisms release energy from food through the controlled oxidative breakdown of food


organisms undergo respiration (呼吸作用 )

• the large amount of heat released in burning kills living cells


12

CO2

H2O

Glucose

O2

ATP

ECOSYSTEM

Sunlight energy

Photosynthesis in chloroplasts

Cellular respiration in mitochondria

(for cellular work)

Heat energy

Photosynthesis and respiration provide energy for life

– Cellular respiration makes ATP and consumes O2

– During the oxidation of glucose to CO2 and H2O

– Cellular respiration makes ATP and consumes O2

– During the oxidation of glucose to CO2 and H2O

13

Respiration ‡ Breathing

breathing supplies oxygen to our cells and removes carbon dioxide

– Breathing provides for the exchange of O2 and CO2 between an organism and its environment

CO2

CO2

O2

O2Bloodstream

Muscle cells carrying out

Cellular Respiration

Breathing

Glucose O2

CO2 H2O ATP

Lungs

Figure 6.2

14

What is respiration?• glucose is the most common substrate


glucose (in the cell)

O2 CO2 + H2O

heat

ATP

15

What is respiration?• respiration:


- a series of reactions

- takes place in all living cells all the time

- controlled by many enzymes

- slow and gradual reactions

16

What is respiration?• overall equation:


enzymesglucose O2 CO2 energyH2O

C6H12O6 CO26 H2O ATPs

Glucose Oxygen gas Carbon dioxide

6

Water Energy

O2 6+ + +

17

The human body uses energy from ATP for all its activities

Table 6.4

ATP powers almost all cellular and body activities

18

What is the role of ATP?• as energy carrier


ADP P

ATP

phosphorylation (磷酸化 )

energy released from respiration

19

What is the role of ATP?22.1 Basic concepts of respiration

ADP P

ATP

breakdown

releases energy to cells

energy released from respiration

• as energy carrier

20

What is the role of ATP?• ATP releases energy for metabolic

activities:


- cell division

- muscle contraction

- transmission of nerve impulse

21

What is the role of ATP?• ATP releases energy for metabolic

activities:


- synthesis of biomolecules

- absorption of food molecules or minerals by active transport

amino acids protein

22

Types of respiration1 Aerobic respiration (需氧呼吸 )


• glucose is completely broken down• a large amount of energy is released

• requires oxygen

23

Types of respiration2 Anaerobic respiration (缺氧呼吸 )


• glucose is only partly broken down

• much less energy is released

• products are different from aerobic respiration

• does not require oxygen

24

22.2 Site of respiration

• some reactions occur in the cytoplasm,some in the mitochondria

25

Adaptive features of a mitochondrion

• outer membrane controls the movement of substances

• bound by a double membrane

22.2 Sites of respiration

outer membrane

3D model

26

Adaptive features of a mitochondrion

provides a large surface area to pack more enzymes

• inner membrane is highly folded


inner membrane

27

Adaptive features of a mitochondrion• mitochondrial matrix (基質 ) provides

a fluid medium for reactions to take place


mitochondrial matrix

• it also contains enzymes

28

Adaptive features of a mitochondrion• most energy in food is released inside

mitochondria


muscle cells

active cells contain many mitochondria

29

22.1


2 Identify various structures of the mitochondrion

30

22.3 Aerobic respiration

• takes place in the presence of oxygen• three stages:

Krebs cycle (克雷伯氏循環 )

glycolysis (糖酵解 )

oxidative phosphorylation (氧化磷酸化 )

31

Food are highly reducedCells tap energy from foods by oxidization

Energy are tapped when electrons “falling” from organic fuels to oxygen

– Electrons lose potential energy• During their transfer from organic compounds to

oxygen

An overview of cellular respiration

NADH

NADH FADH2

GLYCOLYSIS

Glucose Pyruvate CITRIC ACID CYCLE

OXIDATIVE PHOSPHORYLATION

(Electron Transport and Chemiosmosis)

Substrate-level phosphorylation

Oxidative phosphorylation

Mitochondrion

and

High-energy electrons

carried by NADH

ATPATPATP

CO2 CO2

Cytoplasm

Substrate-level phosphorylation

33

– When glucose is converted to carbon dioxide• It loses hydrogen atoms, which are added to

oxygen, producing water

C6H12O6 6 O26 CO2 6 H2O

Loss of hydrogen atoms (oxidation)

Gain of hydrogen atoms (reduction)

Energy

(ATP)Glucose

+ + +

Figure 6.5A

34

Dehydrogenase removes electrons (in hydrogen atoms) from fuel molecules (oxidation)

• And transfers them to NAD+ (reduction)

Figure 6.5B

OH H O 2H

Reduction

Dehydrogenase

(carries

2 electrons)

NAD 2H

2H 2e

NADH H

Oxidation

+

+

+

+

35

– NADH passes electrons to an electron transport chain

– As electrons “fall” from carrier to carrier and finally to O2

• Energy is released in small quantities / controlled

H2O

NAD

NADH

ATP

H

H

Controlled release of energy for

synthesis of ATP

Electron transport

chain

2 O2

2e

2e

1

2

36

Glycolysis22.3 Aerobic respiration

• occurs in the cytoplasm• does not require oxygen

37

– In glycolysis, ATP is used to energize a glucose molecule

– Which is split into two molecules of pyruvate

NAD NADH H

Glucose2 Pyruvate

ATP2P2 ADP

22

2

2

+

+

Figure 6.7A

Glycolysis harvests chemical energy by oxidizing glucose to pyruvate

38


- Breakdown of glucose to triose phosphate

glucose (6-C)

2 ATP

2 ADP + P

2 triose phosphate (3-C)

‘Energy investment’ phase of glycolysis

39

- ATP is used to energize a glucose molecule, which is then split in two Triose phosphate

ATP

Glucose PREPARATORY PHASE

(energy investment)

ADP

Step

Glucose-6-phosphate

Fructose-6-phosphate

P

P

Fructose-1,6-diphosphate

ATP

ADP

PP

Steps – A fuel molecule is energized, using ATP.

Step A six-carbon intermediate splits into two three-carbon intermediates.

1

2

3

44

1 3

Figure 6.7C

‘Energy investment’ phase of glycolysis

40


- Oxidation of triose phosphate to pyruvate


4 ADP + 4 P

4 ATP

2 pyruvate (3-C)

2 NAD+

2 NADH

‘Energy payoff’ phase of glycolysis

41



4 ATP

2 pyruvate (3-C)

2 NAD+

as hydrogen carrier2 NADH


42


- Production of ATP


4 ADP + 4 P

4 ATP

2 pyruvate (3-C)


43

Glycolysis produces ATP by substrate-level phosphorylation

high energy phosphate- carrying molecules are produced in the conversion of TP to pyruvate

a phosphate group is transferred from the high energy phosphate- carrying molecules to ADP

44

Substrate level phosphorylation

high energy molecule


45

Substrate level phosphorylation

The conversion of phosphoenolpyruvate to pyruvate is another example of substrate level phosphorylation.


lower energy molecule

lower energy molecule


46Pyruvate

ATP

ADP

ATP

ADP

P

ATP ATP

ADP ADP

P

2-Phosphoglycerate

P

H2O H2O

Phosphoenolpyruvate(PEP)

Steps – ATP and pyruvate are produced.

P 3 -Phosphoglycerate

P

P

9 9

6 6

7 7

8 8

6 9 Step A redox reaction generates NADH.

P

NADH NADHP

P P P P

P

+H+H

ENERGY PAYOFF PHASE

Glyceraldehyde-3-phosphate(G3P)

1,3 -Diphosphoglycerate

P

5

6 9

5 5

66

7 7

88

9 9

NAD NAD


- ATP, NADH, and pyruvate are formed

Figure 6.7C


47

GlycolysisFree energy level of intermediates and net energy gain:

48

A summary of glycolysis

49


• overall equation:

glucose (6-C)

2 pyruvate (3-C)

2 NAD+ 2 NADH

2 ADP + 2 P 2 ATP

transported to mitochondrion

50

When pyruvate enters a mitochondrion it is converted to acetylCoA. Coenzyme A (CoA) is a large molecule (and a vitamin) that acts as a coenzyme.

The conversion of pyruvate to acetylCoA is an coupled oxidation-reduction reaction in which high energy electrons are removed from pyruvate and end up in NADH. The three carbon pyruvate is split into CO2 and the two carbon acetate.

The link reaction - before entering the Krebs cycle:

51

CO2

Pyruvate

NAD NADH H

CoA

Acetyl CoA(acetyl coenzyme

A)

Coenzyme A

The Link reaction (between glycolysis and Citric acid cycle)

– Prior to the citric acid cycle

– Enzymes process pyruvate, releasing CO2 and producing NADH and acetyl CoA

1

2

3

The link reaction - before entering the Krebs cycle:

52

Fate of pyruvate – with oxygen

53

Kerbs cycle22.3 Aerobic respiration

• occurs in the mitochondrial matrix• two main steps:

1 Combination of acetyl-CoA with 4-C compound

2 Regeneration of 4-C compound

54


1 Combination of acetyl-CoA with 4-C compound

acetyl-CoA (2-C)

4-C compound CoA

6-C compound

55


2 Regeneration of 4-C compound

4-C compound

6-C compound

2 CO2

3 NAD+3 NADHFAD

FADH

ADP + P

ATP

56

and Steps and

CITRIC ACID CYCLE

Oxaloacetate

CoA

CoA

2 carbons enter cycle

Acetyl CoA

Citrate

leaves cycle

H

NAD

NADH

CO2

Alpha-ketoglutarate

leaves cycleCO2

ADP P

NAD

NADH H

ATP

Succinate

FAD

FADH2

Malate

H

NAD

NADH

Step

Acetyl CoA stokes the furnace.

Steps

NADH, ATP, and CO2 are generated during redox reactions.

Redox reactions generate FADH2 and NADH.

For each turn of the cycle

2

2

1

1

3

3

4

4

5

5

Two CO2 molecules are released

The energy yield is

one ATP,

three NADH, and one FADH2

Kerbs cycle

Kerbs / Citric acid / TCA cycle

Guess why it is also called citric acid and TCA

cycle ?

58


• each glucose molecule generates two pyruvate molecules

a total of six NADH,

two FADH2 and

two ATP are formed

a total of six NADH,

two FADH2 and

two ATP are formed

59

Oxidative phosphorylation22.3 Aerobic respiration

• occurs on the inner membrane of the mitochondrion (cristae)

• two main steps:

1 Regeneration of NAD+ and FAD

2 Formation of ATP

60



intermembrane space

inner membrane


61



electron carrier

NADH NAD+

e-

62



+

e-e-

e-

OH2O

NADHFADH2

NAD+FAD H+

63


NADHFADH2

NAD+FAD

2 Formation of ATP

ADP+P

+H+OH2O

ATP

e- e-

e-

64

Oxidative phosphorylation

65


2 Formation of ATP

• one NADH can generate three ATPs

• one FADH2 can generate two ATPs

66

An ad of a pharmaceutical product

67

Vitamins & energy metabolism

Which vitamin group and How they are involved in cellular energy metabolism?

68

Vitamins Involved in Energy MetabolismVitamins and mineralsVitamins and minerals Are required for proper metabolism

Do not directly provide energy

Often function as coenzymescoenzymes

The B-complex vitamins are especially important for energy metabolism.The B-complex vitamins are especially important for energy metabolism.B-complex Vitamins: Thiamin (Vitamin B1)

Coenzyme thiamin is required for carbohydrate metabolism

Beriberi: deficiency of thiamin resulting in muscle wasting and nerve damage, heart failure

B-complex Vitamins: Riboflavin (Vitamin B2)

Part of coenzymes involved in oxidation-reduction reactions

Milk is a good source of riboflavin

B-complex Vitamins: Niacin

Nicotinamide and nicotinic acid

Coenzyme assists with the metabolism of carbohydrates and fatty acids

Good sources: meat, fish, poultry, enriched bread products

Toxicity can result from supplements

69

– Electrons from NADH and FADH2 • Travel down the electron transport chain to

oxygen, which picks up H+ to form water

– Energy released by the redox reactions• Is used to pump H+ into the space between the

mitochondrial membranes (intermembrane space)

Chemiosmosis (reference)

70

70

Mitochondrion Structure

Cristae Matrix

Intermembrane Space

• This drawing shows a mitochondrion cut lengthwise to reveal its internal membrane.

71

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

Outside

Intermembrane Space

Matrix

This drawing shows a close-up of a section of a mitochondrion.

Matrix (inside)

ChemiosmoticPhosphorylation

72

00

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

Outside

Intermembrane Space

Matrix

Matrix (inside)

Menu

Pumps within the membrane moves hydrogen ions from the matrix to the intermembrane space creating a concentration gradient.

H+

H+

H+

73

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

Outside

Intermembrane Space

Matrix

Matrix (inside)

This process requires energy – from passing of e- along ETC

H+

74

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

Outside

Intermembrane Space

Matrix

Matrix (inside)


A high concentration of hydrogen ions in the intermembrane space creates a gradient for diffusion of H+ back to the matrix.

75

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

Outside

Intermembrane Space

Matrix

Matrix (inside)

the hydrogen ions pass through this protein (called ATP synthase) as they return to the matrix down the diffusion gradient.


76

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

H+

ATP

ADP + Pi

H+

Outside

Intermembrane Space

ATP synthase produces ATP by phosphorylating ADP. The energy needed to produce ATP comes from hydrogen ions forcing their way into the matrix as they pass through the

ATP synthase.

Matrix (inside)


77

ATP synthase produces ATP using energy from the proton gradient

78

78

Chemiosmotic Phosphorylation

• Chemiosmotic phosphorylation is used by the mitochondrion to produce ATP. The energy needed to initially pump H+ ions into the intermembrane space comes from glucose. The entire process is called cellular respiration.

• The chloroplast also produces ATP by chemiosmotic phosphorylation. The energy needed to produce ATP comes from sunlight.

79

79

Chloroplast Structure

• The chloroplast is surrounded by a double membrane.

• Molecules that absorb light energy (photosynthetic pigments) are located on disk-shaped structures called thylakoids.

• The interior portion is the stroma.

Thylakoids

Double membraneStroma

80

80

H+

H+

H+

H+H+H+

H+ H+

H+H+

H+H+

H+

H+

H+ H+

A Thylakoid

In order to synthesize ATP, hydrogen ions must first be pumped into the thylakoid. This process requires energy.

81

81

H+

H+

H+

H+H+H+

H+ H+

H+H+

H+H+

H+

H+

H+ H+

A Thylakoid

A concentration gradient of hydrogen ions is established. The chemical gradient can be used as an energy source for producing ATP.

82

82

H+

H+

H+

H+H+H+

H+ H+

H+H+

H+H+

H+

H+

H+ H+

H+

ADP + Pi

ATP

Chemiosmotic Phosphorylation

ATP synthase produces ATP by phosphorylating ADP. The energy comes from hydrogen ions forcing their way into the stroma as they pass through the ATP synthase

hydrogen ions force through this protein (ATP synthase) as they return to the stroma.

83

83

Phosphorylation

• We have just discussed two different forms of phosphorylation:– Substrate-level phosphorylation– Chemiosmotic phosphorylation

• We saw that chemiosmotic phosphorylation occurred in both the mitochondria (during cellular respiration) and in the chloroplast (during photosynthesis). These two processes are sometimes given separate names:

– Oxidative phosphorylation (in mitochondria)– Photophosphorylation (in chloroplast)

84

SimilaritiesSimilarities: In both organelles

–Redox reactions of electron transport chains generate a H+ gradient across a membrane

–Involves ATP synthase which uses this proton-motive force to make ATP

DifferenceDifference:–use different sources of energy to accomplish this (proton gradient). Chloroplasts use light energy (photophosphorylation) and mitochondria use the chemical energy in organic molecules (oxidative phosphorylation).

Chemiosmosis: Chloroplasts vs. Mitochondria

85

– In chemiosmosis, the H+ diffuses back through the inner membrane through ATP synthase complexes --Driving the synthesis of ATP

Intermembrane space

Inner mitochondrial membrane

Mitochondrial matrix

Protein complex

Electron flow

Electron carrier

NADH NAD+

FADH2 FAD

H2OATPADP

ATP synthase

H+ H+ H+

H+

H+H+

H+

H+

H+

H+

H+

H+

H+

H+

P

O2

Electron Transport Chain Chemiosmosis

.

OXIDATIVE PHOSPHORYLATION

+ 212

Chemiosmosis

86

Evidences supporting ChemiosmosisCertain poisons interrupt critical events in cellular respiration

H+

H+

H+

H+

H+

H+ H+ H+ H+

H+

H+

H+

H+

O2

H2OP ATP

NADH NAD+

FADH2 FAD

Rotenone Cyanide, carbon monoxide

Oligomycin

DNP

ATPSynthase

2

ADP

Electron Transport Chain Chemiosmosis

1

2

Figure 6.11

Block the movement of electrons

Block the flow of H+ through ATP synthase

Allow H+ to leak through the membrane

87


2 Formation of ATP (through oxidative phosphorylation)

Pyruvate to acetyl-CoA: 2 NADH

Glycolysis: 2 NADH

Krebs cycle: 6 NADH 2 FADH= 6 ATP = 6 ATP = 22 ATP

Total: 34 ATP

88


Let’s summarize the overall process of aerobic respiration.

Sure!

89


90


enzymes

C6H12O6 6 O2

6 CO2 38 ATP6 H2O

Overall equation:

91

• is split into two molecules of using energy from ATP

Different stages of aerobic respiration:

1 Glycolysis occurs in .Glucose

triose phosphate


cytoplasm

92

; and are formed

• Triose phosphate is oxidized to


1 Glycolysis occurs in .

NADHpyruvate


ATP

cytoplasm

93

• Net amount of ATP formed:


1 Glycolysis occurs in .2


cytoplasm

94

.• Pyruvate is converted to

acetyl-CoA; and NADH are formed


2 Conversion of pyruvate to acetyl-CoA occurs in

carbon dioxide



95



0


.mitochondrial matrix

2 Conversion of pyruvate to acetyl-CoA occurs in

96

• Acetyl-CoA combines with a 4-C compound to form a compound


3 Krebs cycle occurs in mitochondrial matrix.

6-C


97

and ATP are formed

• The 6-C compound is oxidized step by step to regenerate 4-C compound; carbon dioxide, NADH,



FADH


98




2


99

• NADH and FADH lose . They are oxidized to regenerate NAD and FAD


4 Oxidative phosphorylation occurs ininner


membrane of mitochondrion.

hydrogen

100

• The oxidation of NADH and FADH releases energy to form by phosphorylation





ATP

101

• Hydrogen is finally accepted by oxygen to form





water

102






36

103

22.4 Anaerobic respiration

• does not require oxygen

• all reactions occur in the cytoplasm only

• starts with glycolysis but will not proceed to the Kerbs cycle and oxidative phosphorylation

104


How does anaerobic respiration occur?

105

Fate of pyruvate depends on the availability of oxygen

106

Fermentation is an anaerobic alternative to aerobic respiration

– Without O2 as the final electron acceptor, oxidative phosphorylation stops– Under anaerobic conditions, many kinds of cells

• Can use glycolysis alone to produce small amounts of ATP

107

– In glycolysis, ATP is used to energize a glucose molecule

– Which is split into two molecules of pyruvate

NAD NADH H

Glucose2 Pyruvate

ATP2P2 ADP

22

2

2

+

+

Figure 6.7A

Glycolysis harvests chemical energy by oxidizing glucose to pyruvate

108

Fermentation can generate ATP from glucose by substrate-level phosphorylation as long as there is a supply of NAD+ to accept electrons.

•If the NAD+ pool is exhausted, glycolysis shuts down also!

• In aerobic respiration, NAD+ is regenerated in ETC

• Without O2, ETC stops working!!!!!!

• In aerobic respiration, NAD+ is regenerated in ETC

• Without O2, ETC stops working!!!!!!

109

Fermentation is an anaerobic alternative to aerobic respiration to regenerate NAD+

110

In lactic acid fermentation• NADH is oxidized to NAD+ as pyruvate is

reduced to lactate

2 Lactate

NAD NADH NADH NAD2 2 22

2 ATP2 ADP 22 Pyruvate

GLYCOLYSIS

P

Glucose

Figure 6.13A

111

1 Formation of lactic acid (乳酸 ) in muscles


glucose (6-C)2 ADP + 2 P

2 ATP

2 pyruvate (3-C)

2 NAD

2 NADH

glycolysis

112

1 Formation of lactic acid (乳酸 )

in muscles


2 pyruvate (3-C)

2 lactic acid (3-C)

2 NADH

2 NAD+

113


in muscles


• produces only two ATP through glycolysis

• simple and can supply energy quickly

114


in muscles


• the formation of lactic acid by anaerobic respiration is called lactic acid fermentation (乳酸發酵 )


2 lactic acidglucose energy (2 ATP)

115


in muscles


• anaerobic respiration provides additional energy in a very short time allows muscles to

contract more powerfully and at a higher rate

116


in muscles


• lactic acid formed builds up in muscles and causes pain muscle fatigue (肌肉疲勞 )

117


in muscles


• after doing strenuous exercise, our breathing remains deep for some time

amou

nt o

f O2

brea

thed

in

timerest exercise recovery rest

118


in muscles


• extra oxygen is used to break down lactic acid

oxygen debt (氧債 )

amou

nt o

f O2

brea

thed

in


119


in muscles


• lactic acid is broken down to CO2 and water or converted to glycogen

amou

nt o

f O2

brea

thed

in


oxygen debt (氧債 )

120

In alcohol fermentation• NADH is oxidized to NAD+ while converting

pyruvate to CO2 and ethanol

NAD NADH NADH NAD2 2 2 2

GLYCOLYSIS

2 ADP 2 P ATP

Glucose 2 Pyruvate

releasedCO2

2 Ethanol

22

Figure 6.13B

Figure 6.13C

121

2 Formation of ethanol and carbon dioxide in yeast


glucose (6-C)2 ADP + 2 P

2 ATP

2 pyruvate (3-C)

2 NAD

2 NADH

glycolysis

122



2 pyruvate (3-C)

2 ethanol (2-C)

2 NADH

2 NAD2 CO2

123



• the formation of ethanol by anaerobic respiration is called alcoholic fermentation (酒精發酵 )


2 ethanolglucose energy (2 ATP)

2 CO2

124

Brewing of wine involves alcoholic fermnetation

125

How to Measure the rate of respiration of a small animal ?

126

A respirometer

How about plants?

127

Applications of anaerobic respiration


• the brewing of beer makes use of the alcohol formed when yeast ferments the sugar in barley (大麥 )

128

Applications of anaerobic respiration• the brewing of wine

makes use of the alcohol formed when yeast ferments the sugar in grape juice


129

Applications of anaerobic respiration• CO2 formed by alcoholic

fermentation in yeast helps raise dough in bread-making


130

Applications of anaerobic respiration• yoghurt contains lactic

acid formed by anaerobic respiration in bacteria


131

Applications of anaerobic respiration• lactic acid formed by

anaerobic respiration in bacteria helps coagulate milk to form cheese


132

Applications of anaerobic respiration• ethanol formed by the

fermentation of sugar in crops can be used as a fuel to power vehicles


133

1 Anaerobic respiration in skeletal muscles:

Pyruvate is reduced to by .

Glucose undergoes and is oxidized to . NADH and ATP are formed in the process.

glycolysispyruvate


lactic acidNADH

134

2 Anaerobic respiration in provides additional energy in a very short time for .

muscles

muscle contraction


135

3 During strenuous exercise, the

lactic acid


formed by anaerobic respiration accumulates in muscles and causes .muscle fatigue

136

We keep breathing deeply after exercise to take in extra . It is used to remove all lactic acid by breaking it down to and water or converting it to

3oxygen


carbon dioxide

.glycogen

137

4 Anaerobic respiration in yeast:

Pyruvate is reduced to by NADH. is released in the process.

Glucose undergoes glycolysis and is oxidized to pyruvate. NADH and ATP are formed in the process.

ethanolCarbon dioxide


138

5a

Both release energy from the oxidative breakdown of organicsubstances


Similarities of aerobic and anaerobic respiration:

.

139


Both transfer energy to the energy carrier , and some energy is lost as

ATPheat


5a

.

140


Both consist of a number of reactions controlled by .

enzymes


5a

141

5b

Aerobic respiration occurs in cytoplasm and while anaerobic respiration occurs only in

mitochondria

cytoplasm


Differences between aerobic and anaerobic respiration:

.

142

but anaerobic respiration does not.


Aerobic respiration requiresoxygen


5b

143


In aerobic respiration, organic substances are completely broken down into andcarbon dioxide


5b

water .

144


But in anaerobic respiration, organic substances are partly broken down to form or and carbon dioxide.

lactic acid


5b

ethanol

145


In aerobic respiration, ATP per glucose molecule is formed (a larger amount of energy is released).

38


5b

146


In anaerobic respiration, ATP per glucose molecule is formed (a much smaller amount of energy is released).

2


5b

147

6 in yeast is used in brewing beer and , raising dough in bread-making and producing as a biofuel.

Alcoholic fermentationwine


ethanol

148

in bacteria is used in making yoghurt and cheese.


6 Lactic acid fermentation

149

Connection between molecular breakdown and synthesis

• Cells use many kinds of organic molecules as fuel for cellular respiration

150

– Carbohydrates, fats, and proteins can all fuel cellular respiration

• When they are converted to molecules that enter glycolysis or the citric acid cycle

OXIDATIVEPHOSPHORYLATION(Electron Transportand Chemiosmosis)

Food, such aspeanuts

Carbohydrates Fats Proteins

Sugars Glycerol Fatty acids Amino acids

Aminogroups

Glucose G3P Pyruvate AcetylCoA

CITRICACID

CYCLE

ATP

GLYCOLYSIS

Figure 6.14

151

Energy metabolism of carbohydrates, fats, and proteins

152

• Proteins must first be digested to individual a____ acids.

• Amino acids that will be catabolized must have their amino groups removed via deamination.

• The carbon skeletons are modified by enzymes and enter as intermediaries into glycolysis or the citric acid cycle, depending on their structure.

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Intermediates from glycolysis and the citric acid cycle are used as raw materials for making complex organic

Substances

-The biosynthesis of

organic substances

ATP needed to drive biosynthesis

ATP

CITRIC

ACID

CYCLE

GLUCOSE SYNTHESISAcetyl

CoAPyruvate G3P Glucose

Amino

groups

Amino acidsFatty

acidsGlycerol Sugars

CarbohydratesFatsProteins

Cells, tissues, organisms

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The fuel for respiration ultimately comes from photosynthesis

– All organisms

• Can harvest energy from organic molecules

– Plants

• make these molecules from inorganic sources by the process of photosynthesis

Figure 6.16

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22.5 Relationship between respiration and photosynthesis

• exchange of molecules between respiration and photosynthesis

bridges the flow of energy from the environment to organisms

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Exchange of molecules22.5 Relationship between respiration and photosynthesis

photochemical reactions

oxidative phosphorylation

H2O H2O

O2O2

chloroplast mitochondrion

light

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Exchange of molecules22.5 Relationship between respiration and photosynthesis

Calvin cycle

Krebs cycle

CO2 CO2

glucose

glycolysis

pyruvate

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Flow of energy22.5 Relationship between respiration and photosynthesis

photosynthesis

respirationwaterCO2

oxygen

glucose

energy

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In energy transformation22.5 Relationship between respiration and photosynthesis

• ATP acts as the energy carrier

light energy

ADP + P

ATP energy stored in organic

compounds

ADP + P

ATP

energy for cellular

metabolism

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In energy transformation22.5 Relationship between respiration and photosynthesis

• ATP acts as the energy carrier

ADP + P

ATP energy stored in organic

compounds

ADP + P

ATP

energy for cellular

metabolism

light energy

photosynthesis

respiration

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Respiration occurs in all cells while photosynthesis occurs in cells

1 Site of occurrence:

Differences between respiration and photosynthesis:

living

chloroplast-containing


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In respiration, occurs. Organic food is broken down by

to release energy

2 Type of metabolism:


catabolism

oxidation


164

In photosynthesis, occurs. Organic food is built up by

to store energy

Type of metabolism:


anabolism

reduction


2

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In respiration, chemical energy in food is converted to and

3 Energy change:


ATP heat


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In photosynthesis, light energy from the sun is converted toenergy in food

Energy change:


chemical


3

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is removed from the substrate and , and FADH are formed

In Krebs cycle of respiration, 4 Cyclic reactions:


carbon dioxideNADH


ATP

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carbon dioxide is fixed into the cycle by a and NADPHand are used

In Calvin cycle of photosynthesis, 4 Cyclic reactions:


5-C compoundATP


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In respiration, ATP is formed in glycolysis, Krebs cycle and

5 Formation of ATP:




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In photosynthesis, ATP is formed in5 Formation of ATP:


photophosphorylation


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In respiration, and are the hydrogen donors while in photosynthesis, is the hydrogen donor

6 Hydrogen donor:


NADH


FADH

water

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In respiration, is the final hydrogen acceptor while in photosynthesis, a in Calvin cycle is the final hydrogen acceptor

7 Final hydrogen acceptor:


oxygen


3-C compound

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How does our body obtain energy1from the food we eat?Our body releases energy stored in food by respiration. The energy is used to form ATP which drives all cellular activities.

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How is alcohol produced from corn2by fermentation?Sugar in corn is converted to ethanol by alcoholic fermentation in yeast.

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The sugar in corn is made by3photosynthesis. What is the relationship between respiration and photosynthesis?Respiration and photosynthesis together allow the flow of energy in the ecosystem.

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Respiration

is

requires oxygen

does not require oxygen

oxidative breakdown of food

aerobic respiration

anaerobic respiration

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releases

chemical energy

oxidative breakdown of food

mostly as

heat ATP

some stored in

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aerobic respiration

anaerobic respiration

glycolysis

cytoplasm

both involve

occurs in

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glycolysis

if aerobic, then followed by

Kerbs cycle


mitochondriaoccur in

180

glycolysis

if anaerobic, then followed by

formation of lactic acid

formation of ethanol and carbon dioxide

cytoplasmoccur in

1 2 Food like corn can provide energy for the body.

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Transcript of 1 2 Food like corn can provide energy for the body.