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Cellular Respiration
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Cellular Respiration
A catabolic, exergonic, oxygen (O2) requiring process that uses energy extracted from macromolecules (glucose) to produce energy (ATP) and water (H2O).
C6H12O6 + 6O2 6CO2 + 6H2O + energy
glucose ATP
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Question:
In what kinds organisms does cellular respiration take place?
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Plants and Animals
Plants - Autotrophs: self-producers.
Animals - Heterotrophs: consumers.
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Mitochondria
Organelle where cellular respiration takes place.
Inner
membrane
Outer
membrane
Inner
membrane space Matrix
Cristae
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Redox Reaction
Transfer of one or more electrons from one reactant to another.
Two types:
1. Oxidation
2. Reduction
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Oxidation Reaction
The loss of electrons from a substance.
Or the gain of oxygen.
C6H12O6 + 6O2 6CO2 + 6H2O + energy
glucose ATP
Oxidation
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Reduction Reaction
The gain of electrons to a substance.
Or the loss of oxygen.
glucose ATP
C6H12O6 + 6O2 6CO2 + 6H2O + energy
Reduction
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Breakdown of Cellular Respiration
Four main parts (reactions).
1. Glycolysis (splitting of sugar)
a. cytosol, just outside of mitochondria.
2. Grooming Phase
a. migration from cytosol to matrix.
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Breakdown of Cellular Respiration
3. Krebs Cycle (Citric Acid Cycle)
a. mitochondrial matrix
4. Electron Transport Chain (ETC) and
Oxidative Phosphorylation
a. Also called Chemiosmosis
b. inner mitochondrial membrane.
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1. Glycolysis
Occurs in the cytosol just outside of mitochondria.
Two phases (10 steps): A. Energy investment phase
a. Preparatory phase (first 5 steps). B. Energy yielding phase
a. Energy payoff phase (second 5 steps).
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1. Glycolysis
A. Energy Investment Phase:
Glucose (6C)
Glyceraldehyde phosphate (2 - 3C)
(G3P or GAP)
2 ATP - used
0 ATP - produced
0 NADH - produced
2ATP
2ADP + P
C-C-C-C-C-C
C-C-C C-C-C
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1. Glycolysis
B. Energy Yielding Phase
Glyceraldehyde phosphate (2 - 3C)
(G3P or GAP)
Pyruvate (2 - 3C)
(PYR)
0 ATP - used
4 ATP - produced
2 NADH - produced 4ATP
4ADP + P
C-C-C C-C-C
C-C-C C-C-C
GAP GAP
(PYR) (PYR)
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1. Glycolysis
Total Net Yield
2 - 3C-Pyruvate (PYR)
2 - ATP (Substrate-level Phosphorylation)
2 - NADH
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Substrate-Level Phosphorylation
ATP is formed when an enzyme transfers a phosphate group from a substrate to ADP.
Enzyme
Substrate
O-
C=O
C-O-
CH2
P P P Adenosine
ADP (PEP)
Example:
PEP to PYR
P P P
ATP
O-
C=O
C=O
CH2
Product
(Pyruvate)
Adenosine
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Fermentation
Occurs in cytosol when “NO Oxygen” is present (called anaerobic).
Remember: glycolysis is part of fermentation.
Two Types:
1. Alcohol Fermentation
2. Lactic Acid Fermentation
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Alcohol Fermentation
Plants and Fungi beer and wine
glucose
Glycolysis
C
C
C
C
C
C
C
C
C 2 Pyruvic
acid
2ATP 2ADP
+ 2
2NADH
P
2 NAD+
C
C
2 Ethanol 2CO2
released
2NADH 2 NAD+
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Alcohol Fermentation
End Products: Alcohol fermentation
2 - ATP (substrate-level phosphorylation)
2 - CO2
2 - Ethanol’s
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Lactic Acid Fermentation
Animals (pain in muscle after a workout).
2 Lactic
acid
2NADH 2 NAD+
C
C
C
Glucose
Glycolysis C
C
C
2 Pyruvic
acid
2ATP 2ADP
+ 2
2NADH
P
2 NAD+
C
C
C
C
C
C
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Lactic Acid Fermentation
End Products: Lactic acid fermentation
2 - ATP (substrate-level phosphorylation)
2 - Lactic Acids
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2. Grooming Phase
Occurs when Oxygen is present (aerobic).
2 Pyruvate (3C) molecules are transported through the mitochondria membrane to the matrix and is converted to 2 Acetyl CoA (2C) molecules.
Cytosol C
C
C 2 Pyruvate
2 CO2
2 Acetyl CoA
C-C
2NADH 2 NAD+
Matrix
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2. Grooming Phase
End Products: grooming phase
2 - NADH
2 - CO2
2- Acetyl CoA (2C)
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3. Krebs Cycle (Citric Acid Cycle)
Location: mitochondrial matrix.
Acetyl CoA (2C) bonds to Oxalacetic acid (4C - OAA) to make Citrate (6C).
It takes 2 turns of the krebs cycle to oxidize 1 glucose molecule.
Mitochondrial
Matrix
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3. Krebs Cycle (Citric Acid Cycle)
Krebs
Cycle
1 Acetyl CoA (2C)
3 NAD+
3 NADH
FAD
FADH2
ATP ADP + P
(one turn)
OAA (4C) Citrate (6C)
2 CO2
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3. Krebs Cycle (Citric Acid Cycle)
Krebs
Cycle
2 Acetyl CoA (2C)
6 NAD+
6 NADH
2 FAD
2 FADH2
2 ATP 2 ADP + P
(two turns)
OAA (4C) Citrate (6C)
4 CO2
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3. Krebs Cycle (Citric Acid Cycle)
Total net yield (2 turns of krebs cycle)
1. 2 - ATP (substrate-level phosphorylation)
2. 6 - NADH
3. 2 - FADH2
4. 4 - CO2
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4. Electron Transport Chain (ETC) and Oxidative Phosphorylation
(Chemiosmosis)
Location: inner mitochondrial membrane.
Uses ETC (cytochrome proteins) and ATP Synthase (enzyme) to make ATP.
ETC pumps H+ (protons) across innermembrane (lowers pH in innermembrane space).
Inner
Mitochondrial
Membrane
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4. Electron Transport Chain (ETC) and Oxidative Phosphorylation
(Chemiosmosis)
The H+ then move via diffusion (Proton Motive Force) through ATP Synthase to make ATP.
All NADH and FADH2 converted to ATP during this stage of cellular respiration.
Each NADH converts to 3 ATP.
Each FADH2 converts to 2 ATP (enters the ETC at a lower level than NADH).
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4. Electron Transport Chain (ETC) and Oxidative Phosphorylation
(Chemiosmosis)
Inner
membrane
Outer
membrane
Inner
membrane space Matrix
Cristae
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4. ETC and Oxidative Phosphorylation
(Chemiosmosis for NADH)
NADH
+ H+
ATP
Synthas
e
1H+ 2H+ 3H+
higher H+
concentration
H+
ADP + ATP
lower H+
concentration
H+
(Proton Pumping)
P
E T C
NAD+
2H+ + 1/2O2 H2O
Intermembrane Space
Matrix
Inner
Mitochondrial
Membrane
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4. ETC and Oxidative Phosphorylation
(Chemiosmosis for FADH2)
FADH2 + H+
ATP
Synthas
e
1H+ 2H+
higher H+
concentration
H+
ADP + ATP
lower H+
concentration
H+
(Proton Pumping)
P
E T C
FAD+ 2H+ +
1/2O2
H2O
Intermembrane Space
Matrix
Inner
Mitochondrial
Membrane
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TOTAL ATP YIELD
1. 04 ATP - substrate-level phosphorylation
2. 34 ATP - ETC & oxidative phosphorylation
38 ATP - TOTAL YIELD
ATP
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Eukaryotes (Have Membranes)
Total ATP Yield
02 ATP - glycolysis (substrate-level phosphorylation)
04 ATP - converted from 2 NADH - glycolysis
06 ATP - converted from 2 NADH - grooming phase
02 ATP - Krebs cycle (substrate-level phosphorylation)
18 ATP - converted from 6 NADH - Krebs cycle
04 ATP - converted from 2 FADH2 - Krebs cycle
36 ATP - TOTAL
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Maximum ATP Yield for Cellular Respiration (Eukaryotes)
36 ATP (maximum per glucose)
Glucose
Glycolysis
2ATP 4ATP 6ATP 18ATP 4ATP 2ATP
2 ATP (substrate-level
phosphorylation)
2NADH
2NADH
6NADH
Krebs
Cycle
2FADH2
2 ATP (substrate-level
phosphorylation)
2 Pyruvate
2 Acetyl CoA
ETC and Oxidative
Phosphorylation
Cytosol
Mitochondria
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Prokaryotes (Lack Membranes)
Total ATP Yield
02 ATP - glycolysis (substrate-level phosphorylation)
06 ATP - converted from 2 NADH - glycolysis
06 ATP - converted from 2 NADH - grooming phase
02 ATP - Krebs cycle (substrate-level phosphorylation)
18 ATP - converted from 6 NADH - Krebs cycle
04 ATP - converted from 2 FADH2 - Krebs cycle
38 ATP - TOTAL
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Question:
In addition to glucose, what other various food molecules are use in Cellular Respiration?
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Catabolism of Various Food Molecules
Other organic molecules used for fuel.
1. Carbohydrates: polysaccharides
2. Fats: glycerol’s and fatty acids
3. Proteins: amino acids
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