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Respiration
Outline – Cellular Respiration
•
Breathing and Respiration
•
Cellular Aerobic Respiration
•
Efficiency of Respiration
•
Cellular Anaerobic Respiration
•
Respiration of Carbohydrate, Protein & Fat
Fig 6.2
Breathing and Respiration
CO2
O2
Breathing
Lungs
O2
CO2
Bloodstream
Muscle cells
Cellular Respiration
Glucose + O2 CO2 + H2O + ATP
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Cellular Aerobic Respiration
Glucose molecules broken down to CO2
Glucose loses electrons and hydrogen  Oxidation
Oxygen gains electrons and hydrogen  Reduction
Cells tap energy from electrons
Cells bank energy in ATP
Loss of hydrogen
atoms (oxidation)
C6H12O6
+
6 CO2 + 6 H2O
6 O2
Glucose
Gain of hydrogen
atoms (reduction)
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+
ATP (Energy)
Transferring Energy in the cell
Figure 6.5B
Oxidation - Enzyme removes electrons from substrate
Reduction - Electrons in Hydrogen Transferred to NAD+
H
Oxidation
H
O
Dehydrogenase
O + 2H
Enzyme
+
NAD
+ 2H
+
2H
Reduction
+ 2e
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NADH +
(carries
2 electrons)
H+
AEROBIC CELLULAR RESPIRATION
C6H12O6 + 6 O2
6 CO2 + 6 H2O +
Stages
Glycolysis
Chemical Grooming of Pyruvate
Citric acid cycle
Oxidative phosphorylation
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ATP
Cellular Respiration Stage 1: Glycolysis
•
•
•
•
Occurs in the cytoplasm
Breaks down glucose into pyruvate
Reduces coenzyme NAD+
Produces a small amount of ATP
2 NAD+
2 NADH +
2 H+
1 Glucose
2 ADP +
Figure 6.7A
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
2P
2
2 Pyruvate
ATP
Cellular Respiration: Glycolysis
Major steps in glycolysis
1. Preparatory phase: 2 ATP energize glucose
Steps 1 – 3 A fuel molecule is energized,
using ATP.
ATP
ADP
Glucose
PREPARATORY
PHASE
Step
1
P
Glucose-6-phosphate
P
Fructose-6-phosphate
2
ATP
3
ADP
P
P
Step 4 A six-carbon intermediate splits
into two three-carbon intermediates.
Figure 6.7C
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
4
Fructose-1,6bisphosphate
Cellular Respiration: Glycolysis
2. Energy Payoff: NADH+H+ is formed
3. Energy Payoff: ATP is formed
4. Pyruvate is formed
P
Step 5 A redox reaction generates
6
9
NADH.
NAD
+
5
NADH+H+
Steps 6 – 9 ATP and pyruvate
are produced.
P
NAD
P
Glyceraldehyde-3-phosphate
(G3P)
+
P
6
P
P
P
ADP
6
7
ATP
ATP
P
7
P
8
8
H2O
8
2-Phosphoglycerate
8
H2O
P
P
9
ADP
9
7
P 3-Phosphoglycerate
7
ATP
6
P 1,3-Diphosphoglycerate
P
Energy Payoff
ENERGY PAYOFF PHASE
5
NADH+H+
ADP
6
Energy Payoff
Cleavage of 6C sugar
Phosphoenolpyruvate
(PEP) 9
ADP
ATP
9
Pyruvate
Figure 6.7C
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Cellular Respiration: Glycolysis
Glycolysis produces ATP by substrate-level phosphorylation
Enzyme
P
P P Adenosine
ADP
ATP
P
Organic molecule
(substrate)
Figure 6.7B
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P
Cellular Respiration Stage 2: Chemical Grooming of Pyruvate
Pyruvate is oxidized:
1. Releases CO2
2. Produces NADH and acetyl Coenzyme A
3. Acetyl CoA is transferred to the mitochondrion
NAD+
NADH + H+
CoA
Pyruvate
CO2
Figure 6.8
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Coenzyme A
Acetyl
Coenzyme A
Cellular Respiration Stage 3: Citric Acid Cycle
Acetyl CoA
CoA
2 carbons enter cycle
Oxaloacetate
Citrate
NADH
+ H+
CO2
NAD+
NAD+
Malate
NADH
1
+ H+
ADP + P
FADH2
ATP
2 Alpha-ketoglutarate
FAD
Succinate
CO2
4
NAD+
6.9B
NADH
1
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+ H+
2
3
3
4
Stage 3: Citric Acid Cycle
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
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Mitochondrion Structure
Outer
Membrane
Intermembrane
Space
Matrix
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Cristae
Inner
Membrane
Stage 4: Oxidative Phosphorylation
1.Electron Flow occurs in mitochondrial membrane
2.Protons are transported across the inner mitochondrial membrane
H2O
3.ATP is synthesized by Chemiosmosis
H+ H+
+
H
H+ H+
H+
+
H
H+
H+
+
.
H
Intermembrane
space
Inner
mitochondrial
membrane
e-
FADH2
NAD+
H+
H+
H+
Electron Transport Chain
Figure 6.10
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
H+
H+
H+
H
FAD
H+
H+
+
eNADH
Mitochondrial
matrix
H+ H+
H+ +
O H
H2O
H+
Stage 4: Oxidative Phosphorylation
ATP Synthesis by Chemiosmosis
H+
H++
H
H++
H+
H+
H+
+
H
H+
H+
H+
H+
+
H+
H+
H+
H+
H+
H
H+
Electron Transport Chain
ADP
P
ATP
H+
H+
Chemiosmosis by
ATP synthase
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Stage 4: Oxidative Phosphorylation
1.Electron Flow occurs in mitochondrial membrane
2.Protons are transported across the inner mitochondrial membrane
3.ATP is synthesized by Chemiosmosis
H+ H+
.
+
H
H+
Protein
complex
Intermembrane
space
Inner
mitochondrial
membrane
eFigure 6.10
H+
+
H
H+ H+
H+
Electron
carrier
+
H
H
H+
+
H+
+
H
H+
ATP
H+ synthase
ee-
FADH2
NADH
Mitochondrial
matrix
H+ H+
NAD+
+
H
FAD
H+
H+
+
H
O2
H2O
Electron Transport Chain
H+
ADP
P
ATP
Chemiosmosis
OXIDATIVE PHOSPHORYLATION
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H+
Stage 4: Oxidative Phosphorylation
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
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
oligomycin
from the
fungus
Streptomyces
H+
H+
H+
Oligomycin
Cyanide,
carbon
monoxide
H
Rotenone
+
H+
+
H
+
H
H+
+
H
ATP
Synthase
DNP
Young Man
Dies after
Using a Diet
Pill containing
Dinitrophenol
(DNP)
FADH2
FAD
1 O2
NAD+
NADH
+ 2 H+
2
H+
+
H
H2O
H
ADP
+ P
+
Electron Transport Chain
Figure 6.11
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Chemiosmosis
ATP
Genus: Derris
Summary: Aerobic Cellular Respiration
Cytoplasm
Mitochondrion
NADH+H+
GLYCOLYSIS
Pyruvate
Glucose
2 ATP
by substrate-level
phosphorylation
Figure 6.12
Acetyl
CoA
NADH+H+
CITRIC
ACID
CYCLE
FADH2
OXIDATIVE
PHOSPHORYLATION
2 ATP
by substrate-level
phosphorylation
About 38 ATP for each glucose
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34 ATP
by oxidative
phosphorylation
Anaerobic Cellular Respiration
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
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Lactic Acid Fermentation
• NADH is oxidized to NAD+
• Pyruvate is reduced to lactate
NAD+
NADH
NADH
NAD+
GLYCOLYSIS
ADP +
P
ATP
Pyruvate
Glucose
Figure 6.13A
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Lactate
Alcohol Fermentation
• NADH is oxidized to NAD+
• Pyruvate is converted to CO2 and ethanol
NAD+ NADH
Glucose
NADH NAD+
GLYCOLYSIS
ADP + P
ATP
Ethanol
Pyruvate
Figure 6.13B
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CO2
Fuels for Respiration
• Carbohydrates, fats, and proteins converted to molecules
entering
– Glycolysis or citric acid cycle
Food, such as
peanuts
Carbohydrates
Fats
Sugars
Glycerol Fatty acids
Proteins
Amino acids
Amino
groups
Glucose
G3P
Pyruvate
GLYCOLYSIS
Acetyl
CoA
ATP
Figure 6.14
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
CITRIC
ACID
CYCLE
OXIDATIVE
PHOSPHORYLATION
Fuel for respiration comes from photosynthesis
• All organisms
– Respire
• Plants, but not animals
– Respire and Photosynthesize
Figure 6.16
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End Respiration