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1
Food like corn can provide energy for
the body.
2
The sugar in it can also undergo
fermentation (發酵) to produce an alcohol.
3
The alcohol can be used as a fuel to
power vehicles.
4
1
How does our body
obtain energy from the
food we eat
5
2
How is alcohol
produced from corn
by fermentation
6
3
The sugar in corn is
made by photosynthesis.
What is the relationship
between respiration and
photosynthesis
7
22.1 Basic concepts of
respiration
What is respiration?
8
22.1 Basic concepts of respiration
What is respiration?
• when food is burnt, it reacts with oxygen
(oxidation 氧化):
heat
O2
light
CO2 + H2O
glucose
9
22.1 Basic concepts of respiration
What is respiration?
• when food is burnt, it reacts with oxygen
(oxidation 氧化):
- one step reaction
- takes place anywhere
- no enzyme involved
- fast and violent reaction
10
22.1 Basic concepts of respiration
What is respiration?
• the large amount of heat released in
burning kills living cells
 organisms undergo
respiration (呼吸作用)
the process by which organisms release
energy from food through the controlled
oxidative breakdown of food
11
Photosynthesis and respiration
provide energy for life
Sunlight energy
– Cellular respiration
makes ATP and
consumes O2
– During the oxidation of
glucose to CO2 and
H2O
ECOSYSTEM
Photosynthesis in
chloroplasts
CO2
Glucose
+
+
H2O
O2
Cellular respiration in
mitochondria
ATP
(for cellular work)
Heat energy
12
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
O2
Breathing
CO2
Lungs
CO2
Bloodstream
O2
Muscle cells carrying out
Cellular Respiration
Glucose + O2
Figure 6.2
CO2 + H2O + ATP
13
22.1 Basic concepts of respiration
What is respiration?
• glucose is the most common substrate
heat
ATP
O2
CO2 + H2O
glucose
(in the cell)
14
22.1 Basic concepts of respiration
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
15
22.1 Basic concepts of respiration
What is respiration?
• overall equation:
glucose
C6H12O6
Glucose
+
6
CO2
O2
enzymes
O2
Oxygen gas
6
CO2
Carbon
dioxide
H2O
+
6
H2O
Water
energy
+
ATPs
Energy
16
The human body uses energy from ATP for all
its activities
ATP powers
almost all
cellular and
body activities
Table 6.4
17
22.1 Basic concepts of respiration
What is the role of ATP?
• as energy carrier
energy
released
from
respiration
ATP
phosphorylation
(磷酸化)
P
ADP
18
22.1 Basic concepts of respiration
What is the role of ATP?
• as energy carrier
energy
released
from
respiration
releases
energy
to cells
ATP
breakdown
ADP
P
19
22.1 Basic concepts of respiration
What is the role of ATP?
• ATP releases energy for metabolic
activities:
- cell division
- muscle contraction
- transmission of
nerve impulse
20
22.1 Basic concepts of respiration
What is the role of ATP?
• ATP releases energy for metabolic
activities:
- synthesis of biomolecules
amino acids
protein
- absorption of food molecules or
minerals by active transport
21
22.1 Basic concepts of respiration
Types of respiration
1 Aerobic respiration (需氧呼吸)
• requires oxygen
• glucose is completely broken down
• a large amount of energy is released
22
22.1 Basic concepts of respiration
Types of respiration
2 Anaerobic respiration (缺氧呼吸)
• does not require oxygen
• glucose is only partly broken down
• much less energy is released
• products are different from aerobic
respiration
23
22.2 Site of respiration
• some reactions occur in the cytoplasm,
some in the mitochondria
24
22.2 Sites of respiration
Adaptive features of
a mitochondrion
3D model
• bound by a double membrane
• outer membrane controls the movement
of substances
outer membrane
25
22.2 Sites of respiration
Adaptive features of
a mitochondrion
• inner membrane is highly folded
 provides a large surface area to pack
more enzymes
inner membrane
26
22.2 Sites of respiration
Adaptive features of
a mitochondrion
• mitochondrial matrix (基質) provides
a fluid medium for reactions to take place
• it also contains enzymes
mitochondrial matrix
27
22.2 Sites of respiration
Adaptive features of
a mitochondrion
• most energy in food is released inside
mitochondria
 active cells
contain many
mitochondria
muscle cells
28
22.2 Sites of respiration
22.1
2 Identify various structures of the mitochondrion
29
22.3 Aerobic respiration
• takes place in the presence of oxygen
• three stages:
glycolysis (糖酵解)
Krebs cycle (克雷伯氏循環)
oxidative phosphorylation (氧化磷酸化)
30
Food are highly reduced
Cells 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
31
An overview of cellular respiration
NADH
High-energy
electrons
carried by NADH
NADH
FADH2
and
GLYCOLYSIS
Glucose
Pyruvate
CITRIC ACID
CYCLE
OXIDATIVE
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
Mitochondrion
Cytoplasm
ATP
Substrate-level
phosphorylation
CO2
ATP
CO2
Substrate-level
phosphorylation
ATP
Oxidative
phosphorylation
– When glucose is converted to carbon dioxide
•
It loses hydrogen atoms, which are added to
oxygen, producing water
Loss of hydrogen atoms
(oxidation)
C6H12O6
+ 6 O2
6 CO2
+
Glucose
6 H2O
+
Energy
(ATP)
Gain of hydrogen atoms
(reduction)
Figure 6.5A
33
Dehydrogenase removes electrons (in
hydrogen atoms) from fuel molecules (oxidation)
•
And transfers them to NAD+ (reduction)
Oxidation
H
NAD+
Dehydrogenase
Reduction
NADH
2H
+
+
2H
Figure 6.5B
O + 2H
H
O
+
2e

+
H+
(carries
2 electrons)
34
– 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
NADH
NAD
+
H
+
ATP

2e
+
Controlled
release of
energy for
synthesis of
ATP

2e
2
H
+
1
2
O2
H2O
35
22.3 Aerobic respiration
Glycolysis
• occurs in the cytoplasm
• does not require oxygen
36
Glycolysis harvests chemical energy
by oxidizing glucose to pyruvate
– In glycolysis, ATP is used to energize a glucose
molecule
– Which is split into two molecules of pyruvate
2
NAD+
2
NADH
+ 2
H+
Glucose
2 Pyruvate
2 ADP
Figure 6.7A
+2
P
2
ATP
37
A summary
of glycolysis
38
Bad news: glycolysis involves 10 complicated steps!
39
40
Good news: that’s all you need to know in DSE!
• overall equation:
glucose
(6-C)
2 pyruvate
(3-C)
41
Good news: that’s all you need to know in DSE!
• overall equation:
2 NAD+
glucose
(6-C)
2 NADH
2 pyruvate
(3-C)
42
Good news: that’s all you need to know in DSE!
• overall equation:
2 NAD+
glucose
(6-C)
2 ADP + 2 P
2 NADH
2 pyruvate
(3-C)
2 ATP
43
Good news: that’s all you need to know in DSE!
• overall equation:
2 NAD+
glucose
(6-C)
2 ADP + 2 P
2 NADH
2 pyruvate
(3-C)
2 ATP
transported to
mitochondrion
44
22.3 Aerobic respiration
‘Energy investment’ phase of glycolysis
- Breakdown of glucose to triose phosphate
glucose (6-C)
2 ATP
2 ADP + P
2 triose phosphate (3-C)
45
22.3 Aerobic respiration
‘Energy payoff’ phase of glycolysis
- Oxidation of triose phosphate to pyruvate
2 triose phosphate (3-C)
2 NAD+
2 NADH
4 ADP + 4 P
4 ATP
2 pyruvate (3-C)
46
22.3 Aerobic respiration
Glycolysis
- Oxidation of triose phosphate to pyruvate
2 triose phosphate (3-C)
2 NAD+
2 NADH as hydrogen
4 ATPcarrier
2 pyruvate (3-C)
47
22.3 Aerobic respiration
‘Energy payoff’ phase of glycolysis
- Production of ATP
2 triose phosphate (3-C)
4 ADP + 4 P
4 ATP
2 pyruvate (3-C)
48
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
49
Substrate level phosphorylation
high energy
molecule
high energy
molecule
50
Substrate level phosphorylation
high energy
molecule
lower energy
molecule
lower energy
molecule
high energy
molecule
The conversion of phosphoenolpyruvate to pyruvate is
another example of substrate level phosphorylation.
51
Glycolysis
Free energy level of intermediates and net energy
gain:
52
A summary
of glycolysis
53
22.3 Aerobic respiration
Glycolysis
• overall equation:
2 NAD+
glucose
(6-C)
2 ADP + 2 P
2 NADH
2 pyruvate
(3-C)
2 ATP
transported to
mitochondrion
54
The link reaction - before entering the Krebs cycle:
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 oxidationreduction 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.
55
The link reaction - before entering the Krebs cycle:
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
NAD+
NADH
+ H+
2
CoA
Pyruvate
1
3
CO2
Acetyl CoA
(acetyl coenzyme A)
Coenzyme A
56
Fate of pyruvate – with oxygen
57
22.3 Aerobic respiration
Krebs cycle
• occurs in the mitochondrial matrix
• two main steps:
1 Combination of acetyl-CoA
with 4-C compound
2 Regeneration of 4-C compound
58
Bad news: Krebs cycles is very complicated!
59
Good news:
Krebs cycle can be understood in a simple way!
1 Combination of acetyl-CoA with
4-C compound
acetyl-CoA (2-C)
4-C
compound
CoA
6-C compound
60
22.3 Aerobic respiration
Krebs cycle
2 Regeneration of 4-C compound
4-C
compound
6-C
compound
ATP
ADP + P
FADH
FAD
2 CO2
3 NAD+
3 NADH
61
Krebs cycle
CoA
For each turn of the cycle
Acetyl CoA
CoA
2 carbons enter cycle
4C intermediate
Two CO2
molecules are
released
6C Citric acid
NADH
+ H+
CO2
NAD+
The energy yield
is
one ATP,
CITRIC ACID CYCLE
leaves cycle
NAD+
1
4C intermediate
NADH
ADP
+
+ H+
P
5
FADH2
three NADH, and
one FADH2
ATP
2
5C intermediate / alpha-keto acid
FAD
CO2
leaves cycle
4C intermediate
4
NADH
+ H+
NAD+
3
1
2
3
4
5
62
22.3 Aerobic respiration
Krebs cycle
• each glucose molecule generates two
pyruvate molecules
 a total of six NADH,
 two FADH2 and
 two ATP are formed
63
22.3 Aerobic respiration
Oxidative phosphorylation
• occurs on the inner membrane of the
mitochondrion (cristae)
• two main steps:
1 Regeneration of NAD+ and FAD
2 Formation of ATP
64
22.3 Aerobic respiration
Oxidative phosphorylation
1 Regeneration of NAD+ and FAD
intermembrane space
inner
membrane
mitochondrial
matrix
65
22.3 Aerobic respiration
Oxidative phosphorylation
1 Regeneration of NAD+ and FAD
intermembrane space
inner membrane
e-
electron
carrier
mitochondrial matrix
NADH NAD+
66
22.3 Aerobic respiration
Oxidative phosphorylation
1 Regeneration of NAD+ and FAD
e-
e-
NADH NAD+
FADH2 FAD
H2O
H+
e+
O
67
22.3 Aerobic respiration
Oxidative phosphorylation
2 Formation of ATP
e-
e-
NADH NAD+
ADP+P ATP eFADH2 FAD
H+ +
O
H2O
68
22.3 Aerobic respiration
Oxidative phosphorylation
2 Formation of ATP
• one NADH can generate three ATPs
• one FADH2 can generate two ATPs
69
An ad of a pharmaceutical product
70
Vitamins & energy metabolism
Which vitamin group and How they are involved in cellular energy metabolism?71
Vitamins Involved in Energy Metabolism
Vitamins and minerals
Are required for proper metabolism
Do not directly provide energy
Often function as
coenzymes
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
72
Net Energy Production from Aerobic
Respiration
73
Chemiosmosis (reference)
– 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)
74
22.3 Aerobic respiration
Oxidative phosphorylation
Formation of ATP…… HOW?
e-
e-
NADH NAD+
ADP+P ATP eFADH2 FAD
H+ +
O
H2O
75
The ‘chemiosmosis’ theory
76
The ‘chemiosmosis’ theory
77
Mitochondrion Structure
• This drawing shows a mitochondrion cut
lengthwise to reveal its internal membrane.
Intermembrane Space
Cristae
78
Matrix
78
This drawing shows a close-up
of a section of a mitochondrion.
Chemiosmotic
Phosphorylation
H+
H+
Matrix
(inside)
H+
H+
Intermembrane Space
H+
H+
H+
H+
Outside
Matrix
H+
H+
H+
H+
79
H+
Pumps within the membrane moves hydrogen ions from the matrix to the
intermembrane space creating a concentration gradient.
H+
H+
Outside
Matrix
(inside)
H+
H+
H+
00
H+
H+
H+
H+
H+
Intermembrane Space
Matrix
H+
H+
H+
H+
H+
80
H+
Menu
This process requires energy – from passing of e- along ETC
H+
H+
Outside
Matrix
(inside)
H+
H+
H+
H+
H+
H+
H+
H+
Intermembrane Space
Matrix
H+
H+
H+
81
H+
A high concentration of hydrogen ions in the
intermembrane space creates a gradient for diffusion
of H+ back to the matrix.
H+
Chemiosmotic
Phosphorylation
Outside
Matrix
(inside)
H+
H+
H+
H+
H+
H+
H+
Intermembrane Space
Matrix
H+
H+
H+
82
H+
the hydrogen ions pass through this protein (called ATP
Chemiosmotic
synthase) as they return to the matrix down the
Phosphorylation
diffusion gradient.
+
H
H+
Outside
Matrix
(inside)
H+
H+
H+
H+
H+
H+
H+
Intermembrane Space
Matrix
H+
H+
H+
H+
83
H+
H+
H+
Matrix
(inside)
Chemiosmotic
Phosphorylation
H+
H+ H+
ATP
H+
Intermembrane Space
H+
H+
ADP + Pi
Outside
H+
H+
H+
H+
ATP synthase produces ATP by phosphorylating ADP. The
+
energy needed to produce ATP comesHfrom
hydrogen ions
forcing their way into the matrix
as they pass through the
+
H
ATP synthase.
84
ATP synthase produces ATP
using energy from the proton gradient
https://www.youtub
e.com/watch?v=lRl
TBRPv6xM
85
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.
86
86
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.
Stroma
Double membrane
Thylakoids
87
87
A Thylakoid
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+ H+
H+
In order to synthesize ATP, hydrogen ions
must first be pumped into the thylakoid. This
process requires energy.
88
88
A Thylakoid
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
H + H+
H+
A concentration gradient of hydrogen ions is
established. The chemical gradient can be
used as an energy source for producing ATP.
89
89
Chemiosmotic Phosphorylation
H+
hydrogen ions force through this protein (ATP
synthase) as they return to the stroma.
H+
H+
H+
H+
H+
ADP + Pi
H+
H+
H+
H+
H+
H+
H+ H+
H+
ATP
H+
90
ATP synthase produces ATP by
phosphorylating+ADP. The energy
H
comes from hydrogen ions forcing
their way into the stroma as they pass
90
through the ATP synthase
Phosphorylation
• We have just discussed two different forms of
phosphorylation:
– Substrate-level phosphorylation
– Chemiosmotic phosphorylation (involves the ETC)
• 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)
91
91
Chemiosmosis:
Chloroplasts vs. Mitochondria
Similarities: 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
Difference:
–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).
92
Chemiosmosis
– In chemiosmosis, the H+ diffuses back through the
inner membrane through ATP synthase complexes
--Driving the synthesis of ATP
H+
H+
H+
H+
+
.
H
H+
Protein
complex
H+
Electron
carrier
Intermembrane
space
H+
H+
ATP
synthase
Inner
mitochondrial
membrane
FADH2
Electron
flow
FAD
NAD+
NADH
+
H
1
O + 2 H+
2 2
+
Mitochondrial
matrix
H
H+
Electron Transport Chain
H2O
ADP
+
P
ATP
H+
Chemiosmosis
93
OXIDATIVE PHOSPHORYLATION
Evidences supporting Chemiosmosis
Certain poisons interrupt critical events in cellular
respiration
Cyanide,
Rotenone
Oligomycin
carbon monoxide
Block the movement of
electrons
H+
H+
H+
H+
Block the flow of
through ATP synthase
H+
H+
H
H+ H+ H+
Allow H+ to leak
through the membrane
+
ATP
Synthase
DNP
FADH2
FAD
1 O 2 + 2 H+
2
NAD+
NADH
H+
H+
H2O
ADP + P
ATP
H+
Electron Transport Chain
Figure 6.11
Chemiosmosis
94
22.3 Aerobic respiration
Oxidative phosphorylation
2 Formation of ATP (through oxidative phosphorylation)
Glycolysis:
2 NADH
Pyruvate to
acetyl-CoA:
2 NADH
Krebs cycle:
6 NADH
2 FADH
= 6 ATP
= 6 ATP
= 22 ATP
Total: 34 ATP
95
22.3 Aerobic respiration
Let’s summarize the
overall process of
aerobic respiration.
96
22.3 Aerobic respiration
97
22.3 Aerobic respiration
Overall equation:
C6H12O6
6 O2
enzymes
6 CO2
6 H2O
38 ATP
98
Want to
watch a video?
99
22.3 Aerobic respiration
Different stages of aerobic
respiration:
1 Glycolysis occurs in cytoplasm .
• Glucose is split into two
molecules of triose phosphate
using energy from ATP
100
22.3 Aerobic respiration
Different stages of aerobic
respiration:
1 Glycolysis occurs in cytoplasm .
• Triose phosphate is oxidized to
pyruvate ; NADH and ATP
are formed
101
22.3 Aerobic respiration
Different stages of aerobic
respiration:
1 Glycolysis occurs in cytoplasm .
• Net amount of ATP formed: 2
102
22.3 Aerobic respiration
Different stages of aerobic
respiration:
2 Conversion of pyruvate to
acetyl-CoA occurs in
mitochondrial matrix .
• Pyruvate is converted to
acetyl-CoA; carbon dioxide and
NADH are formed
103
22.3 Aerobic respiration
Different stages of aerobic
respiration:
2 Conversion of pyruvate to
acetyl-CoA occurs in
mitochondrial matrix .
• Net amount of ATP formed: 0
104
22.3 Aerobic respiration
Different stages of aerobic
respiration:
3 Krebs cycle occurs in mitochondrial
matrix.
• Acetyl-CoA combines with a 4-C
compound to form a 6-C
compound
105
22.3 Aerobic respiration
Different stages of aerobic
respiration:
3 Krebs cycle occurs in mitochondrial
matrix.
• The 6-C compound is oxidized
step by step to regenerate 4-C
compound; carbon dioxide, NADH,
FADH and ATP are formed
106
22.3 Aerobic respiration
Different stages of aerobic
respiration:
3 Krebs cycle occurs in mitochondrial
matrix.
• Net amount of ATP formed: 2
107
22.3 Aerobic respiration
Different stages of aerobic
respiration:
4 Oxidative phosphorylation occurs in
inner membrane of mitochondrion.
• NADH and FADH lose hydrogen .
They are oxidized to regenerate
NAD and FAD
108
22.3 Aerobic respiration
Different stages of aerobic
respiration:
4 Oxidative phosphorylation occurs in
inner membrane of mitochondrion.
• The oxidation of NADH and FADH
releases energy to form ATP by
phosphorylation
109
22.3 Aerobic respiration
Different stages of aerobic
respiration:
4 Oxidative phosphorylation occurs in
inner membrane of mitochondrion.
• Hydrogen is finally accepted by
oxygen to form water
110
22.3 Aerobic respiration
Different stages of aerobic
respiration:
4 Oxidative phosphorylation occurs in
inner membrane of mitochondrion.
• Net amount of ATP formed: 36
111
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
112
22.4 Anaerobic respiration
How does anaerobic
respiration occur?
113
Fate of pyruvate depends on the
availability of oxygen
114
Fermentation is an anaerobic
alternative to aerobic respiration
– Without O2 as the final electron acceptor,
oxidative phosphorylation stops, Krebs
cycle cannot proceed….
why?
– Under anaerobic conditions, many kinds
of cells
• Can use glycolysis alone to
produce small amounts of ATP
115
Glycolysis harvests chemical energy
by oxidizing glucose to pyruvate
– In glycolysis, ATP is used to energize a glucose
molecule
– Which is split into two molecules of pyruvate
2
NAD+
2
NADH
+ 2
H+
Glucose
2 Pyruvate
2 ADP
Figure 6.7A
+2
P
2
ATP
116
Fermentation can generate ATP
from glucose by substrate-level
phosphorylation as long as there is a
supply of NAD+ to accept electrons.
•
In aerobic respiration, NAD+ is
regenerated in ETC
•
Without O2, ETC stops working!!!!!!
•If the NAD+ pool is exhausted,
glycolysis shuts down also!
117
In aerobic respiration, NAD+ is regenerated thro
ETC, with O2 as the final e acceptor.
Fermentation is an anaerobic alternative to aerobic
respiration to regenerate NAD+
118
In lactic acid fermentation
•
2
NADH is oxidized to NAD+ as pyruvate is
reduced to lactate
NAD+
2
2
NADH
NADH
2
NAD+
GLYCOLYSIS
2 ADP + 2
P
2
ATP
2 Pyruvate
2 Lactate
Glucose
Figure 6.13A
119
22.4 Anaerobic respiration
1 Formation of lactic acid (乳酸)
in muscles
glucose (6-C)
2 ADP + 2 P
2 NAD
2 ATP
2 NADH
2 pyruvate (3-C)
glycolysis
120
22.4 Anaerobic respiration
1 Formation of lactic acid (乳酸)
in muscles
Reduced 2 pyruvate (3-C)
2 NADH
2 NAD+
oxidized 2 lactic acid (3-C)
121
22.4 Anaerobic respiration
1 Formation of lactic acid (乳酸)
in muscles
Reduced 2 pyruvate (3-C)
2 NADH
oxidized
2 NAD+
oxidized 2 lactic acid (3-C) Reduced
122
22.4 Anaerobic respiration
1 Formation of lactic acid (乳酸)
in muscles
• produces only two ATP through
glycolysis
• simple and can supply energy quickly
123
22.4 Anaerobic respiration
1 Formation of lactic acid (乳酸)
in muscles
• the formation of lactic acid by anaerobic
respiration is called lactic acid
fermentation (乳酸發酵)
• overall equation:
glucose
energy (2 ATP)
2 lactic acid
124
22.4 Anaerobic respiration
1 Formation of lactic acid (乳酸)
in muscles
• anaerobic respiration provides
additional energy in a very short time
 allows muscles to
contract more powerfully
and at a higher rate
125
22.4 Anaerobic respiration
1 Formation of lactic acid (乳酸)
in muscles
• lactic acid formed builds up in muscles
and causes pain
 muscle fatigue (肌肉疲勞)
126
22.4 Anaerobic respiration
amount of O2
breathed in
1 Formation of lactic acid (乳酸)
in muscles
rest exercise recovery
rest
time
• after doing strenuous exercise, our
breathing remains deep for some time
127
22.4 Anaerobic respiration
amount of O2
breathed in
1 Formation of lactic acid (乳酸)
in muscles
oxygen debt (氧債)
rest exercise recovery
rest
time
• extra oxygen is used to break down
lactic acid
128
22.4 Anaerobic respiration
amount of O2
breathed in
1 Formation of lactic acid (乳酸)
in muscles
oxygen debt (氧債)
rest exercise recovery
rest
time
• lactic acid is broken down to CO2 and
water or converted to glycogen
129
In alcohol fermentation
•
NADH is oxidized to NAD+ while converting
pyruvate to CO2 and ethanol
NAD+
2
2
2
NADH
NADH
2
NAD+
GLYCOLYSIS
2 ADP + 2
Glucose
P
2
2
ATP
2 Pyruvate
CO2
released
2 Ethanol
Figure 6.13B
Figure 6.13C
130
22.4 Anaerobic respiration
2 Formation of ethanol and
carbon dioxide in yeast
glucose (6-C)
2 ADP + 2 P
2 NAD
2 ATP
2 NADH
2 pyruvate (3-C)
glycolysis
131
22.4 Anaerobic respiration
2 Formation of ethanol and
carbon dioxide in yeast
2 pyruvate (3-C)
2 NADH
2 CO2
2 NAD
2 ethanol (2-C)
132
22.4 Anaerobic respiration
2 Formation of ethanol and
carbon dioxide in yeast
• the formation of ethanol by anaerobic
respiration is called alcoholic
fermentation (酒精發酵)
• overall equation:
glucose
energy
(2 ATP)
2 ethanol
2 CO2
133
Brewing of wine involves
alcoholic fermnetation
134
How to Measure the rate of
respiration of a small animal ?
135
A respirometer
How about plants?
136
22.4 Anaerobic respiration
Applications of anaerobic
respiration
• the brewing of beer makes
use of the alcohol formed
when yeast ferments the
sugar in barley (大麥)
137
22.4 Anaerobic respiration
Applications of anaerobic
respiration
• the brewing of wine
makes use of the
alcohol formed when
yeast ferments the
sugar in grape juice
138
22.4 Anaerobic respiration
Applications of anaerobic
respiration
• CO2 formed by alcoholic
fermentation in yeast helps
raise dough in breadmaking
139
22.4 Anaerobic respiration
Applications of anaerobic
respiration
• yoghurt contains lactic
acid formed by anaerobic
respiration in bacteria
140
22.4 Anaerobic respiration
Applications of anaerobic
respiration
• lactic acid formed by
anaerobic respiration
in bacteria helps
coagulate milk to
form cheese
141
22.4 Anaerobic respiration
Applications of anaerobic
respiration
• ethanol formed by the
fermentation of sugar
in crops can be used
as a fuel to power
vehicles
142
22.4 Anaerobic respiration
1 Anaerobic respiration in
skeletal muscles:
Glucose undergoes glycolysis
and is oxidized to pyruvate . NADH
and ATP are formed in the process.
Pyruvate is reduced to lactic acid
by NADH .
143
22.4 Anaerobic respiration
2 Anaerobic respiration in
muscles
provides additional energy in a very
short time for muscle contraction .
144
22.4 Anaerobic respiration
3 During strenuous exercise, the
lactic acid formed by anaerobic
respiration accumulates in muscles
and causes muscle fatigue .
145
22.4 Anaerobic respiration
3 We keep breathing deeply after
exercise to take in extra oxygen .
It is used to remove all lactic acid by
breaking it down to carbon dioxide
and water or converting it to
glycogen .
146
22.4 Anaerobic respiration
4 Anaerobic respiration in yeast:
Glucose undergoes glycolysis and
is oxidized to pyruvate. NADH and
ATP are formed in the process.
Pyruvate is reduced to ethanol
by NADH. Carbon dioxide is
released in the process.
147
22.4 Anaerobic respiration
5a
Similarities of aerobic and
anaerobic respiration:
Both release energy from the
oxidative breakdown of organic
substances .
148
22.4 Anaerobic respiration
5a
Similarities of aerobic and
anaerobic respiration:
Both transfer energy to the energy
carrier ATP , and some energy is
lost as heat .
149
22.4 Anaerobic respiration
5a
Similarities of aerobic and
anaerobic respiration:
Both consist of a number of
reactions controlled by enzymes .
150
22.4 Anaerobic respiration
5b Differences between aerobic
and anaerobic respiration:
Aerobic respiration occurs in
cytoplasm and mitochondria
while anaerobic respiration occurs
only in cytoplasm .
151
22.4 Anaerobic respiration
5b Differences between aerobic
and anaerobic respiration:
Aerobic respiration requires
oxygen but anaerobic
respiration does not.
152
22.4 Anaerobic respiration
5b Differences between aerobic
and anaerobic respiration:
In aerobic respiration, organic
substances are completely broken
down into carbon dioxide and
water .
153
22.4 Anaerobic respiration
5b Differences between aerobic
and anaerobic respiration:
But in anaerobic respiration,
organic substances are partly
broken down to form lactic acid
or ethanol and carbon dioxide.
154
22.4 Anaerobic respiration
5b Differences between aerobic
and anaerobic respiration:
In aerobic respiration, 38 ATP per
glucose molecule is formed (a
larger amount of energy is
released).
155
22.4 Anaerobic respiration
5b Differences between aerobic
and anaerobic respiration:
In anaerobic respiration, 2 ATP
per glucose molecule is formed
(a much smaller amount of energy
is released).
156
22.4 Anaerobic respiration
6
Alcoholic fermentation in yeast is
used in brewing beer and wine ,
raising dough in bread-making and
producing ethanol as a biofuel.
157
22.4 Anaerobic respiration
6 Lactic acid fermentation
in
bacteria is used in making yoghurt
and cheese.
158
Connection between
molecular breakdown and
synthesis
• Cells use many kinds of organic molecules
as fuel for cellular respiration
159
– Carbohydrates, fats, and proteins can all fuel
cellular respiration
•
When they are converted to molecules that enter glycolysis or the citric
acid cycle
Food, such as
peanuts
Carbohydrates
Fats
Sugars
Glycerol
Proteins
Fatty acids
Amino acids
Amino
groups
Glucose
G3P
Pyruvate
Acetyl
CoA
CITRIC
ACID
CYCLE
OXIDATIVE
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
GLYCOLYSIS
Figure 6.14
ATP
160
Energy
metabolism of
carbohydrates,
fats, and
proteins
161
• Fats are first digested into gly_____ and f____ acids.
glycerol and fatty acids
A fat molecule
162
glycerol can be converted into to
triose phosphate / PGAL
Which enters glycolytic pathway
163
• Fatty acids are broken down into 2 carbon residues
which combine with Coenzyme A and becomes acetyl COA and
enters the K____ cycle
164
• Proteins must first be digested to individual a____ acids.
•
Amino acids that will be catabolized must have their amino groups
removed via deamination or transamination.
165
166
•
The carbon skeletons are
modified by enzymes and enter as
intermediaries into glycolysis or
the citric acid cycle, depending on
their structure.
167
•
The carbon skeletons are modified by enzymes and enter as
intermediaries into glycolysis or the citric acid cycle, depending on
their structure.
168
•
Catabolism of energy-giving foods:
169
Intermediates from glycolysis and the citric
acid cycle are used as raw materials for making
complex organic substances - The biosynthesis of
organic substances
170
Intermediates from glycolysis and the citric
acid cycle are used as raw materials for making
complex organic
ATP needed to drive biosynthesis
Substances
ATP
-The biosynthesis of
CITRIC
organic substances
ACID
GLUCOSE SYNTHESIS
Acetyl
Pyruvate
CoA
G3P
Glucose
CYCLE
Amino
groups
Amino acids
Fatty
Glycerol
Sugars
acids
Proteins
Fats
Carbohydrates
Cells, tissues, organisms
171
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
172
22.5 Relationship between
respiration and photosynthesis
• exchange of molecules between
respiration and photosynthesis
 bridges the flow of energy from the
environment to organisms
173
22.5 Relationship between respiration and photosynthesis
Exchange of molecules
light
H2O
H2O
photochemical
reactions
oxidative
phosphorylation
chloroplast mitochondrion
O2
O2
174
22.5 Relationship between respiration and photosynthesis
Exchange of molecules
CO2
CO2
Calvin
cycle
Krebs
cycle
glycolysis
glucose
pyruvate
175
22.5 Relationship between respiration and photosynthesis
Flow of energy
oxygen
glucose
photosynthesis
CO2
water
respiration
176
22.5 Relationship between respiration and photosynthesis
In energy transformation
• ATP acts as the energy carrier
energy
stored in
organic
compounds
ATP
light
energy
energy for
cellular
metabolism
ADP
+P
ADP
+P
ATP
177
22.5 Relationship between respiration and photosynthesis
In energy transformation
• ATP acts as the energy carrier
energy
stored in
photosynthesis organic
ADP
compounds
+P
ATP
light
energy
energy for
cellular
metabolism
ADP
+P
respiration
ATP
178
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
1 Site of occurrence:
Respiration occurs in all living
cells while photosynthesis occurs in
chloroplast-containing cells
179
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
2 Type of metabolism:
In respiration, catabolism occurs.
Organic food is broken down by
oxidation to release energy
180
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
2 Type of metabolism:
In photosynthesis, anabolism
occurs. Organic food is built up by
reduction to store energy
181
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
3 Energy change:
In respiration, chemical energy in
food is converted to ATP and heat
182
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
3 Energy change:
In photosynthesis, light energy from
the sun is converted to chemical
energy in food
183
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
4 Cyclic reactions:
In Krebs cycle of respiration,
carbon dioxide is removed from
the substrate and ATP , NADH
and FADH are formed
184
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
4 Cyclic reactions:
In Calvin cycle of photosynthesis,
carbon dioxide is fixed into the cycle
by a 5-C compound and NADPH
and ATP are used
185
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
5 Formation of ATP:
In respiration, ATP is formed in
glycolysis, Krebs cycle and
oxidative phosphorylation
186
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
5 Formation of ATP:
In photosynthesis, ATP is formed in
photophosphorylation
187
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
6 Hydrogen donor:
In respiration, NADH and FADH
are the hydrogen donors while in
photosynthesis, water is the
hydrogen donor
188
22.5 Relationship between respiration and photosynthesis
Differences between respiration
and photosynthesis:
7 Final hydrogen acceptor:
In respiration, oxygen is the final
hydrogen acceptor while in
photosynthesis, a 3-C compound
in Calvin cycle is the final hydrogen
acceptor
189
1
How does our body obtain energy
from 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.
190
2
How is alcohol produced from corn
by fermentation?
Sugar in corn is converted to ethanol by
alcoholic fermentation in yeast.
191
3
The sugar in corn is made by
photosynthesis. What is the relationship
between respiration and photosynthesis?
Respiration and photosynthesis together
allow the flow of energy in the ecosystem.
192
Respiration
is
requires
oxygen
does not
require
oxygen
anaerobic
aerobic
respiration respiration
oxidative
breakdown of food
193
oxidative
breakdown of food
releases
chemical energy
mostly as
heat
some
stored in
ATP
194
aerobic
respiration
anaerobic
respiration
both involve
glycolysis
occurs in
cytoplasm
195
glycolysis
if aerobic, then
followed by
Kerbs
cycle
occur in
oxidative
phosphorylation
mitochondria
196
glycolysis
if anaerobic,
then followed by
formation of
lactic acid
occur in
formation of ethanol
and carbon dioxide
cytoplasm
197