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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Chapter 9Chapter 9
Cellular Respiration: Harvesting Chemical Energy
高醫 生物醫學暨環境生物學系
助理教授 張學偉
http://genomed.dlearn.kmu.edu.tw
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Energy
– Flows into an ecosystem as sunlight and leaves as heat Light energy
ECOSYSTEM
CO2 + H2O
Photosynthesisin chloroplasts
Cellular respiration
in mitochondria
Organicmolecules
+ O2
ATP
powers most cellular work
Heatenergy
Figure 9.2
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• To keep working, cells must regenerate ATP
本圖補充
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• An overview of cellular respiration
Figure 9.6
Electronscarried
via NADH
GlycolysisGlucos
ePyruvate
ATP
Substrate-levelphosphorylation
Electrons carried via NADH and
FADH2
Citric acid cycle
Oxidativephosphorylation:
electron transport and
chemiosmosis
ATPATP
Substrate-levelphosphorylation
Oxidativephosphorylation
MitochondrionCytosol
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Concept
1: Catabolic pathways yield energy by oxidizing organic fuels
2: Glycolysis harvests energy by oxidizing glucose to pyruvate
3: The citric acid cycle completes the energy-yielding oxidation of organic molecules
4: During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis
5: Fermentation enables some cells to produce ATP without the use of oxygen
6: Glycolysis and the citric acid cycle connect to many other metabolic pathways
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Concept 9.1: Catabolic pathways yield energy by oxidizing organic fuels
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Catabolic pathways ( 異化 ) yield energy by oxidizing organic fuels
同化作用
exergonic (產能的 ) endergonic 耗能的
Catabolic Pathways and Production of ATP
本圖為補充
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• One catabolic process, fermentation (發酵 )
– Is a partial degradation of sugars that occurs without oxygen
Conecept 5: Fermentation enables some cells to produce ATP without the use of oxygen
稍後再講
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Cellular respiration
– Is the most prevalent and efficient catabolic pathway
– Consumes oxygen (with O2 as the ultimate electron acceptor) and organic molecules such as glucose
– Yields ATP
It is called cellular respiration to distinguish it from the respiration of breathing.
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Redox Reactions: Oxidation and Reduction
• Catabolic pathways yield energy
– Due to the transfer of electrons
The Principle of Redox
• Redox reactions
– Transfer electrons from one reactant to another by oxidation and reduction
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Definition of Oxidation & Reduction and its agent
• In oxidation
– A substance loses electrons, or is oxidized
• In reduction
– A substance gains electrons, or is reduced
Reducting Agent
Oxidating Agent
Na + Cl Na+ + Cl–
becomes oxidized(loses electron)
becomes reduced(gains electron)
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Some redox reactions
– Do not completely exchange electrons
– Change the degree of electron sharing in covalent bonds
CH4
H
H
HH
C O O O O OC
H H
Methane(reducingagent)
Oxygen(oxidizingagent)
Carbon dioxide Water
+ 2O2 CO2 + Energy + 2 H2O
becomes oxidized
becomes reduced
Reactants Products
Figure 9.3
注意 : blue ball 位置
注意 : blue ball 位置
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Oxidation of Organic Fuel Molecules During Cellular Respiration
• During cellular respiration:
- Glucose is oxidized in a series of steps and oxygen is reduced
C6H12O6 + 6O2 6CO2 + 6H2O + Energy
becomes oxidized
becomes reduced
△G = - 686 Kcal
△G < 0 1. spontaneous reaction (without an input of energy)2. Liberating energy
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
NAD+
H
O
O
O O–
O
O O–
O
O
O
P
P
CH2
CH2
HO OHH
HHO OH
HO
H
H
N+
C NH2
HN
H
NH2
N
N
Nicotinamide(oxidized form)
NH2+ 2[H]
(from food)
Dehydrogenase
Reduction of NAD+
Oxidation of NADH
2 e– + 2 H+
2 e– + H+
NADH
OH H
N
C +
Nicotinamide(reduced form)
N
Figure 9.4
H+
H+
NAD+ = Nicotinamide adenine dinucleotide
Stepwise Energy Harvest via NAD+ and the Electron Transport Chain
adenine
• Nucleotide = Base + Sugar + Phosphate
• Nucleosides = Sugar + Base (no phosphate)
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Electrons from organic compounds
– Are usually first transferred to NAD+, a coenzyme
NAD+
H
O
O
O O–
O
O O–
O
O
O
P
P
CH2
CH2
HO OHH
HHO OH
HO
H
H
N+
C NH2
HN
H
NH2
N
N
Nicotinamide(oxidized form)
NH2+ 2[H]
(from food)
Dehydrogenase
Reduction of NAD+
Oxidation of NADH
2 e– + 2 H+
2 e– + H+
NADH
OH H
N
C +
Nicotinamide(reduced form)
N
Figure 9.4
H+
H+
Hydrogen atom
protonelectron
2 H 2H+ +2e- (oxidation) NAD+ + H+ +2e- NADH (reduction)= NAD+ + 2H NADH + H+
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
A is the electron donor (so it is oxidized) FAD & NAD(P) is the electron acceptor (so it is reduced).
The products of the reaction are B (oxidized state) FADH2 or NAD(P)H (reduced state) .
Ex. A B + 2H+ +2e- (oxidation)
(+) FAD + 2H+ +2e- FADH2 (reduction)
= A+ FAD <=> B+ FADH2
A+ FAD <=> B+ FADH2A+ NAD(P) <=> B+ NAD(P)H
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
圖形為補充
• NADH passes the electrons to the electron transport chain
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• If electron transfer is not stepwise
– A large release of energy occurs
– As in the reaction of hydrogen and oxygen to form water
(a) Uncontrolled reaction
Fre
e en
ergy
, G
H2O
Explosiverelease of
heat and lightenergy
Figure 9.5 A
H2 + 1/2 O2
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
比較 The electron transport chain
• Passes electrons in a series of steps instead of in one explosive reaction
• Uses the energy from the electron transfer to form ATP
2 H 1/2 O2
(from food via NADH)
2 H+ + 2 e–
2 H+
2 e–
H2O
1/2 O2
Controlled release of energy for synthesis of
ATP ATP
ATP
ATPE
lectron
transp
ort ch
ain
Fre
e en
ergy
, G
(b) Cellular respiration
+
Figure 9.5 B
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• An overview of cellular respiration
Figure 9.6
Electronscarried
via NADH
GlycolsisGlucos
ePyruvate
ATP
Substrate-levelphosphorylation
Electrons carried via NADH and
FADH2
Citric acid cycle
Oxidativephosphorylation:
electron transport and
chemiosmosis
ATPATP
Substrate-levelphosphorylation
Oxidativephosphorylation
MitochondrionCytosol
1 23
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Glycolysis
– Breaks down glucose into two molecules of pyruvate
• The citric acid cycle
– Completes the breakdown of glucose
• Oxidative phosphorylation
– Is driven by the electron transport chain
– Generates ATP
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
substrate-level phosphorylation
• generate ATP from glycolysis and TCA cycle
Figure 9.7
Enzyme Enzyme
ATP
ADP
Product
SubstrateP
+
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Concept 9.2: Glycolysis harvests energy by oxidizing glucose to pyruvate
• Glycolysis
– Means “splitting of sugar”
– Breaks down glucose into pyruvate
– Occurs in the cytoplasm of the cell
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Glycolysis consists of two major phases
– Energy investment phase
– Energy payoff phase
Glycolysis Citricacidcycle
Oxidativephosphorylation
ATP ATP ATP
2 ATP
4 ATP
used
formed
Glucose
2 ATP + 2 P
4 ADP + 4 P
2 NAD+ + 4 e- + 4 H + 2 NADH + 2 H+
2 Pyruvate + 2 H2O
Energy investment phase
Energy payoff phase
Glucose 2 Pyruvate + 2 H2O
4 ATP formed – 2 ATP used 2 ATP
2 NAD+ + 4 e– + 4 H + 2 NADH
+ 2 H+
Net Rx
Net Rx: Glucose + 2ADP+ 2Pi + NAD+ 2 Pyruvate + 2ATP + 2NADH + 2 H+
Figure 9.8
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 9.9 A
investment phase
H H
H
HH
OHOH
HOOH
CH2O
H H
H
HO H
OH
HOOH
P
CH2O P
H
OH
HO
HO
HOH
CH2OH
P O CH2 O CH2 O P
HOH
HO
HOH
OP CH2
C O
CH2OH
H
C
CHOH
CH2
O
O P
ATP
ADP
Hexokinase
Glucose
Glucose-6-phosphate
Fructose-6-phosphate
ATP
ADP
Phosphoglucoisomerase
Phosphofructokinase
Fructose-1, 6-bisphosphate
Aldolase
Isomerase
1
2
3
4
5
O
H
OH
Dihydroxyacetonephosphate
Glyceraldehyde-3-phosphate
CH2OH
GlycolysisCitricacid
cycle
Oxidativephosphorylation
2 NAD+
NADH2+ 2 H+
Triose phosphatedehydrogenase
2 P i
2P C
CHOH
O
P
O
CH2 O
2 O–
1, 3-Bisphosphoglycerate2 ADP
2 ATP
Phosphoglycerokinase
CH2 O P
2
C
CHOH
3-Phosphoglycerate
Phosphoglyceromutase
O–
C
C
CH2OH
H O P
2-Phosphoglycerate
2 H2O
2 O–
Enolase
C
C
O
PO
CH2
Phosphoenolpyruvate2 ADP
2 ATP
Pyruvate kinase
O–
C
C
O
O
CH3
2
6
8
7
9
10
Pyruvate
O
Figure 9.8
payoff phase
KinaseisomeraseMutaseAldolaseenolaseDehydrogenase
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Concept 9.3: The citric acid cycle completes the energy-yielding oxidation of organic molecules
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• The citric acid cycle
– Takes place in the matrix of the mitochondrion
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Before citric acid cycle can begin
– Pyruvate must first be converted to acetyl CoA, which links the cycle to glycolysis
CYTOSOL MITOCHONDRION
NADH + H+NAD+
2
31
CO2 Coenzyme APyruvate
Acetyle CoA
S CoA
C
CH3
O
Transport protein
O–
O
O
C
C
CH3
Figure 9.10
From Vit B
Pyruvate Oxidation
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• An overview of the citric acid cycle
ATP
2 CO2
3 NAD+
3 NADH
+ 3 H+
ADP + P i
FAD
FADH2
Citricacidcycle
CoA
CoA
Acetyle CoA
NADH+ 3 H+
CoA
CO2
Pyruvate(from glycolysis,2 molecules per glucose)
ATP ATP ATP
Glycolysis Citricacidcycle
Oxidativephosphorylation
Figure 9.11
= TCA (Tricarboxyl acid)
= Krebs Cycle
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Acetyl CoA
NADH
Oxaloacetate
CitrateMalate
Fumarate
SuccinateSuccinyl
CoA
-Ketoglutarate
Isocitrate
Citricacidcycle
S CoA
CoA SH
NADH
NADH
FADH2
FAD
GTP GDP
NAD+
ADP
P i
NAD+
CO2
CO2
CoA SH
CoA SH
CoAS
H2O
+ H+
+ H+ H2O
C
CH3
O
O C COO–
CH2
COO–
COO–
CH2
HO C COO–
CH2
COO–
COO–
COO–
CH2
HC COO–
HO CHCOO–
CH
CH2
COO–
HO
COO–
CH
HC
COO–
COO–
CH2
CH2
COO–
COO–
CH2
CH2
C O
COO–
CH2
CH2
C O
COO–
1
2
3
4
5
6
7
8
Glycolysis Oxidativephosphorylation
NAD+
+ H+
ATP
Citricacidcycle
A closer look at the citric acid cycle
Figure 9.12
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Figure 9.12
Acetyl CoA
NADH
Oxaloacetate
CitrateMalate
Fumarate
SuccinateSuccinyl
CoA
-Ketoglutarate
Isocitrate
Citricacidcycle
S CoA
CoA SH
NADH
NADH
FADH2
FAD
GTP GDP
NAD+
ADP
P i
NAD+
CO2
CO2
CoA SH
CoA SH
CoAS
H2O
+ H+
+ H+ H2O
C
CH3
O
O C COO–
CH2
COO–
COO–
CH2
HO C COO–
CH2
COO–
COO–
COO–
CH2
HC COO–
HO CHCOO–
CH
CH2
COO–
HO
COO–
CH
HC
COO–
COO–
CH2
CH2
COO–
COO–
CH2
CH2
C O
COO–
CH2
CH2
C O
COO–
1
2
3
4
5
6
7
8
Glycolysis Oxidativephosphorylation
NAD+
+ H+
ATP
Citricacidcycle
Figure 9.12
A closer look at the citric acid cycle
pyruvate
NAD + CoA NADH + CO2
3C 2C
6C
6C
5C
4C4C
4C
4C
4C
½ Glucose
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Energetics
DHase
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Concept 9.4: During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
An overview of cellular respiration
Figure 9.6
Electronscarried
via NADH
GlycolsisGlucose Pyruvate
ATP
Substrate-levelphosphorylation
Electrons carried via NADH and
FADH2
Citric acid cycle
Oxidativephosphorylation:electron transport
andchemiosmosis
ATPATP
Substrate-levelphosphorylation
Oxidativephosphorylation
MitochondrionCytosol
• NADH and FADH2: Donate electrons to the electron transport chain (ETC), which powers ATP synthesis via oxidative phosphorylation
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
The Pathway of Electron Transport
• In the ETC
– Electrons from NADH and FADH2
lose energy in several steps
H2O
O2
NADH
FADH2
FMN
Fe•S Fe•S
Fe•S
O
FAD
Cyt b
Cyt c1
Cyt c
Cyt a
Cyt a3
2 H + + 12
I
II
III
IV
Multiproteincomplexes
0
10
20
30
40
50
Fre
e e
ner
gy
(G)
rela
tive
to O
2 (k
cl/m
ol)
Figure 9.13
• At the end of the chain
– Electrons are passed to oxygen, forming water
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Chemiosmosis: The Energy-Coupling Mechanism
• ATP synthase is the enzyme that actually makes ATP
INTERMEMBRANE SPACE
H+
H+
H+
H+
H+
H+ H+
H+
P i
+ADP
ATP
A rotor within the membrane spins clockwise whenH+ flows past it down the H+
gradient.
A stator anchoredin the membraneholds the knobstationary.
A rod (for “stalk”)extending into the knob alsospins, activatingcatalytic sites inthe knob.
Three catalytic sites in the
stationary knobjoin inorganic Phosphate to ADPto make ATP.
MITOCHONDRIAL MATRIXFigure 9.14
注意 : H+& ATP的方向
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• At certain steps along the electron transport chain
– Electron transfer causes protein complexes to pump H+ from the mitochondrial matrix to the intermembrane space. [逆反應 ; 與產生 ATP時的 H+運送方向相反 ]
目的 : resulting H+ gradient
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• The resulting H+ gradient
– Stores energy
– Is referred to as a proton-motive force
– Drives chemiosmosis in ATP synthase
• Chemiosmosis
– Is an energy-coupling mechanism that uses energy in the form of a H+ gradient across a membrane to drive cellular work
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Chemiosmosis & electron transport chain
Oxidativephosphorylation.electron transportand chemiosmosis
Glycolysis
ATP ATP ATP
InnerMitochondrialmembrane
H+
H+H+
H+
H+
ATPP i
Protein complexof electron carners
Cyt c
I
II
III
IV
(Carrying electronsfrom, food)
NADH+
FADH2
NAD+
FAD+ 2 H+ + 1/2 O2
H2O
ADP +
Electron transport chainElectron transport and pumping of protons (H+),
which create an H+ gradient across the membrane
ChemiosmosisATP synthesis powered by the flowOf H+ back across the membrane
ATPsynthase
Q
Oxidative phosphorylation
Intermembranespace
Innermitochondrialmembrane
Mitochondrialmatrix
Figure 9.15
NADH 3 ATP; FADH2 2 ATP
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An Accounting of ATP Production by Cellular Respiration
Electron shuttlesspan membrane
CYTOSOL 2 NADH
2 FADH2
2 NADH 6 NADH 2 FADH22 NADH
Glycolysis
Glucose2
Pyruvate
2AcetylCoA
Citricacidcycle
Oxidativephosphorylation:electron transport
andchemiosmosis
MITOCHONDRION
by substrate-levelphosphorylation
by substrate-levelphosphorylation
by oxidative phosphorylation, dependingon which shuttle transports electronsfrom NADH in cytosol
Maximum per glucose:About
36 or 38 ATP
+ 2 ATP + 2 ATP + about 32 or 34 ATP
or
Figure 9.16
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DHAP/GA3P shuttle
Malate/Asp shuttle
Shuttles for transfer of reducing equivalents from cytosol into mitochondria
補充 不考
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1 Pyruvate + NAD+ + CoASH 1 Acetyl-CoA + 1 NADH + CO2
TCA
Pyruvate Oxidation
Glycolysis Pyruvate Oxidation TCA 2 ATP2 NADH (2H)
2 (2x1) NADH
2 (2x1) GTP/ATP6 (2x3) NADH2 (2x1) FADH2
Glucose +2ADP + 2Pi+ 2NAD+ 2 pyruvate +2ATP+2NADH+2H++2H2O
2 Pyruvate + 2 NAD+ + 2 CoASH 2 Acetyl-CoA + 2 NADH + 2 CO2
Glycolysis (aerobic)
2 Acetyl-CoA + 4 H2O + 6 NAD+ + 2FAD + 2GDP + 2 Pi 2 CO2 + 6 NADH + 2 FADH2 + 2 CoA-SH + 2 GTP
aerobic
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Glycolysis Pyruvate Oxidation TCA 2 ATP2 NADH (2H)
2 (2x1) NADH
2 (2x1) GTP/ATP6 (2x3) NADH2 (2x1) FADH2
EST & chemiosmosisNADH 3 ATP; FADH2 2 ATP
ATP 8 6 2 + 18 + 4 = 38 or (6) shuttle = 36
Glycolysis (aerobic)
• About 40% of the energy in a glucose molecule
– Is transferred to ATP during cellular respiration, making approximately 38 ATP
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• Concept 9.5: Fermentation enables some cells to produce ATP without the use of oxygen
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Cellular respiration
– Relies on oxygen to produce ATP
• In the absence of oxygen [no cellular respiration]
– Cells can still produce ATP through fermentation
• fermentation is a partial degradation of sugars that occurs without oxygen
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• Glycolysis
– Can produce ATP with or without oxygen, in aerobic or anaerobic conditions
• Fermentation consists of
– Glycolysis + reactions that regenerate NAD+, which can be reused by glyocolysis
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2 ADP + 2 P1 2 ATP
GlycolysisGlucose
2 NAD+ 2 NADH
2 Pyruvate
2 Acetaldehyde 2 Ethanol
(a) Alcohol fermentation
2 ADP + 2 P1 2 ATP
GlycolysisGlucose
2 NAD+ 2 NADH
2 Lactate
(b) Lactic acid fermentation
H
H OH
CH3
C
O –
OC
C O
CH3
H
C O
CH3
O–
C O
C O
CH3O
C O
C OHH
CH3
CO22
Figure 9.17
3C
2C
3C
3C
• alcohol fermentation
– Pyruvate is converted to ethanol in two steps, one of which releases CO2
• lactic acid fermentation
– Pyruvate is reduced directly to NADH to form lactate as a waste product
Types of Fermentation
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• Anaerobic metabolism
Figure 9.6
Electronscarried
via NADH
GlycolsisGlucos
ePyruvate
ATP
Substrate-levelphosphorylation
Electrons carried via NADH and
FADH2
Citric acid cycle
Oxidativephosphorylation:
electron transport and
chemiosmosis
ATPATP
Substrate-levelphosphorylation
Oxidativephosphorylation
MitochondrionCytosol lactate
Orethanol
2 1x2 32-34
23x22x2
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• Pyruvate is a key juncture in catabolism
Glucose
CYTOSOL
Pyruvate
No O2 presentFermentation
O2 present Cellular respiration
Ethanolor
lactate
Acetyl CoA
MITOCHONDRION
Citricacidcycle
Figure 9.18
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Summaries of Glycolysis
1. anaerobicGlucose -> 2 Lactate + 2 ATP (lactic acid fermentation)Glucose -> 2 Ethanol + 2 ATP (alcoholic fermentation)
2. aerobicGlucose -> 2 Pyruvate + 2ATP + 2NADH (aerobic subtotal)
註 : 2 NADH -> 6 ATP (aerobic conversion: 氧化磷酸化 )
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Fermentation and Cellular Respiration Compared
• 相同點
Use glycolysis to oxidize glucose and other organic fuels to pyruvate
• 相異點1.Differ in their final electron acceptor
Fermentation by acetylaldehyde (ethanol ferment.); by pyruvate (lactate ferment.)
Cellular Respiration by O2
2.Cellular respiration produces more ATP
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The Evolutionary Significance of Glycolysis
• Glycolysis
– Occurs in nearly all organisms
– Probably evolved in ancient prokaryotes before there was oxygen in the atmosphere
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• Concept 9.6: Glycolysis and the citric acid cycle connect to many other metabolic pathways
The Versatility of Catabolism
• Catabolic pathways
– Funnel electrons from many kinds of organic molecules into cellular respiration
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• The catabolism of various molecules from food
Amino acids
Sugars Glycerol Fattyacids
Glycolysis
Glucose
Glyceraldehyde-3- P
Pyruvate
Acetyl CoA
NH3
Citricacidcycle
Oxidativephosphorylation
FatsProteins Carbohydrates
Figure 9.19
-oxidation
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Biosynthesis (Anabolic Pathways)
• The body
– Uses small molecules to build other substances
• These small molecules
– May come directly from food or through glycolysis or the citric acid cycle
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Regulation of Cellular Respiration via Feedback Mechanisms
• Cellular respiration is controlled by allosteric enzymes (e.g., Phosphofructokinase) at key points in glycolysis and the citric acid cycle
Allosteric regulation (see glossary)The binding of a molecule to a protein that affects the function of the protein at a different site.
補充圖
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• The control of cellular respirationGlucose
Glycolysis
Fructose-6-phosphate
Phosphofructokinase
Fructose-1,6-bisphosphateInhibits Inhibits
Pyruvate
ATPAcetyl CoA
Citricacidcycle
Citrate
Oxidativephosphorylation
Stimulates
AMP
+
– –
Figure 9.20
• ATP AMP + ppi