cellular respiration chemical products have a lower how we
TRANSCRIPT
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Cellular Respiration How we harvest energy from food
Today�s topics • Oxidation and Reduction • Glycolysis
– glucose à pyruvate, ATP, NADH
– in cytoplasm • Mitochondria
– Structure and function
• Citric Acid cycle (if time)
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Atoms bonded in High Potential Energy Configuration
Atoms bonded in Low Potential Energy Configuration
Chemical Products have a lower Potential Energy than Reactants
Energy is Released
If one thing gets oxidized, another becomes reduced
Transfer of electrons from A to B
Reactants
becomes oxidized
Methane
Products
Energy
becomes reduced
Oxygen Carbon dioxide Water
Sometimes an electron Is only partially lost or gained
Change in the degree of electron sharing in covalent bonds
Oxidation, Reduction, and Energy
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• Direct ATP production – �Substrate Level Phosphorylation�
• Electron Carriers - NAD, NADP, FAD
– Can �cash in� reduced carriers for ATP – �Oxidative Phosphorylation�
How is energy harvested upon oxidation?
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ATP
Adenine
3 phosphate groups Ribose
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Electron Carriers
• NAD+ nicotinamide adenine dinucleotide NAD+ + H+ + 2e- -> NADH
• NADP+ nicotinamide adenine dinucleotide phosphate NADP+ + H+ + 2e- -> NADPH
• FAD flavin adenine dinucleotide FAD + 2H+ + 2e- -> FADH2
NAD+/NADH Is an Electron Carrier
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Many Small
Controlled reactions
15 gallons Of gasoline
Your cells harvest energy from glucose in small steps
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Amino acids
Sugars Glycerol Fatty acids
Glycolysis Glucose
Glyceraldehyde-3- P
Pyruvate
Acetyl CoA
NH3
Citric acid
cycle
Oxidative phosphorylation
Fats Proteins Carbohydrates
Catabolic Pathways
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General Catabolic Pathway • Step down the oxidation series of carbon in a series of small Steps
Some activation step Oxidation step, with energy harvest
Reorganization step Another oxidation step, another harvest
Another reorganization etc. etc.
yield product of pathway
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Amino acids
Sugars Glycerol Fatty acids
Glycolysis
Glucose
Glyceraldehyde-3- P
Pyruvate
Acetyl CoA
NH3
Citric acid
cycle
Oxidative phosphorylation
Fats Proteins Carbohydrates
Figure 9.19
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Glucose
(Two) 3 carbon acids
oxidized to pyruvate
Glycolysis:
6 carbon sugar Harvest
ATP and NADH
In Cytoplasm
On Inner Mitochondrial membrane
In Mitochondrial Matrix
Steps in the oxidation of glucose
For each process: What goes in? What comes out? Where does it happen? Keep track of the carbon atoms. Keep track of the energy molecules.
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Glycolysis Summary
Energy investment phase
Energy harvest phase
This is the amount of detail you should know 18 Dihydroxyacetone phosphate
Glyceraldehyde- 3-phosphate
H H
H
H H
OH OH
HO HO
CH2OH H H
H
H O H
OH HO
OH
P
CH2O P
H
O H
HO
HO
H HO
CH2OH
P O CH2 O CH2 O P
HO H HO
H OH
O P 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
CH2OH
Figure 9.9 A
2 of these
Glycolysis- the details Energy InvestmentStage
Add P (from ATP) Rearrange
Add P (from ATP)
Split into two 3 carbon units
Rearrange
Do Not Memorize! Just notice the sequential changes
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NADH + 2 H+
P i
2 P C
CHOH
O
P
O
CH2 O
2 O–
1, 3-Bisphosphoglycerate
ATP
CH2 O P
2
C
CHOH
3-Phosphoglycerate
O–
C
C
CH2OH
H O P
2-Phosphoglycerate
2 H2O
2 O–
Enolase
C
C
O
P O
CH2 Phosphoenolpyruvate
ATP O–
C
C
O
O
CH3
2
6
8
7
9
10
O
Figure 9.8 B
Pyruvate x2
2 X Glyceraldehyde-3-P
Glycolysis Energy payoff this pathway happens twice for each glucose
Oxidize aldehyde to acid add another phosphate
Harvest NADH
Make ATP by Substrate Level Phosphorylation
Rearrange
Oxidize alcohol to ketone
Make ATP by Substrate Level Phosphorylation
O
Do Not Memorize! Just notice the sequential changes
Do Not Memorize!
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Substrate-level Phosphorylation
Figure 9.6-3
Electrons carried
via NADH
Electrons carried via NADH and
FADH2
Citric acid cycle
Pyruvate oxidation
Acetyl CoA
Glycolysis
Glucose Pyruvate
Oxidative phosphorylation: electron transport
and chemiosmosis
CYTOSOL MITOCHONDRION
ATP ATP ATP
Substrate-level phosphorylation
Substrate-level phosphorylation
Oxidative phosphorylation
What happens to the products of glycolysis?
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Matrix
Inner Membrane
Intermembrane Space
Outer Membrane
Mitochondrion
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Amino acids
Sugars Glycerol Fatty acids
Glycolysis
Glucose
Glyceraldehyde-3- P
Pyruvate
Acetyl CoA
NH3
Citric acid
cycle
Oxidative phosphorylation
Fats Proteins Carbohydrates