Respiration
Respiration
• Breathing and Respiration
• Cellular Aerobic Respiration
• Efficiency of Respiration
• Cellular Anaerobic Respiration
• Respiration of Carbohydrate, Protein & Fat
Outline – Cellular Respiration
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
CO2
O2
Bloodstream
Muscle cells
Cellular Respiration
Breathing
Glucose O2 CO2 H2O ATP
Lungs
Fig 6.2 Breathing and Respiration
O2
CO2
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Glucose molecules broken down to CO2
Glucose loses electrons and hydrogen Oxidation
Oxygen gains electrons and hydrogen Reduction
Cells tap energy from electronsCells tap energy from electrons
Cells bank energy in ATPCells bank energy in ATP
C6H12O6 6 O2 6 CO2 6 H2O (Energy)ATP
Glucose
+ + +
Loss of hydrogen atoms (oxidation)
Gain of hydrogen atoms (reduction)
Cellular Aerobic Respiration
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Oxidation - Enzyme removes electrons from substrate
Reduction - Electrons in Hydrogen Transferred to NAD+
Figure 6.5B
OH H O 2H
Reduction
Dehydrogenase Enzyme
(carries2 electrons)
NAD 2H
2H 2e
NADH H
Oxidation
+
+
+
+
Transferring Energy in the cell
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
AEROBIC CELLULAR RESPIRATION
Stages
Glycolysis
Chemical Grooming of Pyruvate
Citric acid cycle
Oxidative phosphorylation
C6H12O6 6 O2 6 CO2 6 H2O ATP+ + +
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
2 NAD 2 NADH 2 H
1 Glucose 2 PyruvateATP22 P2 ADP +
+
Figure 6.7A
Cellular Respiration Stage 1: Glycolysis
• Occurs in the cytoplasm• Breaks down glucose into pyruvate• Reduces coenzyme NAD+
• Produces a small amount of ATP
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Major steps in glycolysis
1. Preparatory phase: 2 ATP energize glucose
ATPGlucose
PREPARATORY PHASE
ADP
Step
Glucose-6-phosphate
Fructose-6-phosphate
P
P
Fructose-1,6-bisphosphate
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
Cellular Respiration: Glycolysis
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
PyruvateATP
ADP
ATPADP
P
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+H P
P P P P
P
ENERGY PAYOFF PHASE
Glyceraldehyde-3-phosphate(G3P)
1,3 -Diphosphoglycerate
P
5
6 9
5 5
66
7 7
88
9 9
NAD NAD
2. Energy Payoff: NADH+H+ is formed
3. Energy Payoff: ATP is formed
4. Pyruvate is formed
Figure 6.7C
Cellular Respiration: Glycolysis
ATP
NADH+H
Cleavage of 6C sugar
Energy Payoff
Energy Payoff
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Glycolysis produces ATP by substrate-level phosphorylation
Enzyme
Adenosine
Organic molecule(substrate)
ADP ATP
P
PP P
P
Figure 6.7B
Cellular Respiration: Glycolysis
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
CO2
Pyruvate
NAD NADH H
CoA
Acetyl Coenzyme ACoenzyme A
Figure 6.8
Pyruvate is oxidized:
1. Releases CO2
2. Produces NADH and acetyl Coenzyme A
3. Acetyl CoA is transferred to the mitochondrion
Cellular Respiration Stage 2: Chemical Grooming of Pyruvate
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Oxaloacetate
CoA2 carbons enter cycle
Acetyl CoA
Citrate
NAD
CO2
Alpha-ketoglutarate
CO2
ADP + P
NAD
ATP
Succinate
FAD
FADH2
Malate
NAD
NADH H
Figure 6.9B 2
2
1
1
3
3
4
4
NADH H
Cellular Respiration Stage 3: Citric Acid Cycle
NADH H
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1. Completely oxidizes “glucose” to CO2
2. Produces a small amount of ATP
3. Supplies electrons to last stage of cellular respiration by reducing Coenzymes FAD & NAD
Stage 3: Citric Acid Cycle
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Mitochondrion Structure
OuterMembrane
InnerMembrane
Cristae
Matrix
Intermembrane Space
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1.Electron Flow occurs in mitochondrial membrane
2.Protons are transported across the inner mitochondrial membrane
3.ATP is synthesized by Chemiosmosis
Intermembrane space
Inner mitochondrial membrane
Mitochondrial matrix
NAD+
FAD
H2O
H+ H+ H+
H+
H+ H+
H+H+
H+
H+
Electron Transport Chain
.
Figure 6.10
Stage 4: Oxidative Phosphorylation
NADH
FADH2e-
e-
H+
H+
H+H+
H+
H+H+H+
H+H+
H+
H+
H+
O H+
H2O
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Stage 4: Oxidative Phosphorylation
ATP Synthesis by Chemiosmosis
ATP
H+
H+ H+
H+
H+
H+H+
H+
H+
H+
Chemiosmosis by ATP synthase
Electron Transport Chain ADPP
H+
H+ H+H+ H+
H+
H+H+H+H+ H+H+H+
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
1.Electron Flow occurs in mitochondrial membrane
2.Protons are transported across the inner mitochondrial membrane
3.ATP is synthesized by Chemiosmosis
Intermembrane space
Inner mitochondrial membrane
Mitochondrial matrix
Protein complex Electron
carrier
NAD+
FAD
H2O
ATP synthase
H+ H+ H+
H+
H+ H+
H+H+
H+
H+ ATPADP P
H+O2
Electron Transport Chain Chemiosmosis
.
OXIDATIVE PHOSPHORYLATIONFigure 6.10
Stage 4: Oxidative Phosphorylation
NADH
FADH2e-
e-
e-
H+
H+
H+H+
H+
H+H+H+
H+H+
H+ H+
H+
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
1. Occurs in the mitochondria
2. Uses the energy released by electrons to pump H+ across a membrane
3. Harnesses the energy of the H+ gradient through chemiosmosis, producing ATP
Stage 4: Oxidative Phosphorylation
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Oxidative Phosphorylation Connection
Certain poisons interrupt oxidative phosphorylation
Rotenone blocks the movement of electrons
Oligomycin blocks H+ flow through ATP synthase
DNP allows H+ to leak through the membrane
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
Genus: Derris
Young Man Dies after Using a Diet Pill containing Dinitrophenol (DNP)
oligomycin from the fungusStreptomyces
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
NADH+H+
Cytoplasm Mitochondrion
GLYCOLYSIS
Glucose Pyruvate
by substrate-level
phosphorylation
by substrate-level phosphorylation
by oxidative phosphorylation
OXIDATIVE
PHOSPHORYLATION
AcetylCoA
CITRIC ACID
CYCLE
About 38 ATP for each glucose
FADH2
Figure 6.12
Summary: Aerobic Cellular Respiration
NADH+H+
2 ATP 34 ATP2 ATP
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Fermentation = an anaerobic alternative to cellular respiration
Uses glycolysis alone to produce small amounts of ATP
Types of fermentation
1. Lactic acid fermentation
2. Alcoholic fermentation
Anaerobic Cellular Respiration
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• NADH is oxidized to NAD+
• Pyruvate is reduced to lactate
Lactate
NAD NADH NADH NAD
ATPADP Pyruvate
GLYCOLYSIS
P
Glucose
Figure 6.13A
Lactic Acid Fermentation
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• NADH is oxidized to NAD+
• Pyruvate is converted to CO2 and ethanol
NAD NADH NADH NAD
GLYCOLYSIS
ADP P ATP
Glucose
Pyruvate CO2
Ethanol
Figure 6.13B
Alcohol Fermentation
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• Carbohydrates, fats, and proteins converted to molecules entering
– Glycolysis or citric acid cycle
OXIDATIVE
PHOSPHORYLATION
Food, such as peanuts
Carbohydrates Fats Proteins
Sugars Glycerol Fatty acids Amino acids
Aminogroups
Glucose G3P Pyruvate AcetylCoA
CITRICACID
CYCLE
ATP
GLYCOLYSIS
Figure 6.14
Fuels for Respiration
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Fuel for respiration comes from photosynthesis
• All organisms
– Respire
• Plants, but not animals
– Respire and Photosynthesize
Figure 6.16
End Respiration