Download THE CELLULAR RESPIRATION SAGA II: THE CITRIC ACID CYCLE

9/10/2015
THE CELLULAR RESPIRATION SAGA II:
THE CITRIC ACID CYCLE & OXIDATIVE PHOSPHORYLATION
PLAYERS OF CELLULAR RESPIRATION
NAD+ is a coenzyme that is reduced to NADH using electrons
NAD+
+ 2H
Becomes reduced
2 H+ + 2
NADH
H+
(carries)
2 electrons)
2
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PLAYERS OF CELLULAR RESPIRATION
Electron transport chains
NAD+
NADH
Energy released
and available
for making
2
ATP
2
1
−
2
O2
H2O
2 H+
3
Figure 6.6-0
Electrons carried by NADH
Glycolysis
Glucose
Pyruvate
CYTOSOL
MITOCHONDRION
ATP
ATP
ATP
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GLYCOLYSIS
Takes place in cytoplasm of all living organisms
ATP
• 4 ATP’s made (synthesized)
• ‐2 ATP’s invested
= 2 net ATP’s via substrate level phosphorylation
•
ATP
2 Pyruvate molecules synthesized from 1 glucose
• No Oxygen required!
• 2 NAD+s reduced to NADH’s
= 4 electrons stolen
NADH
NADH
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CELLULAR RESPIRATION Glycolysis, fermentation and pyruvate oxidation
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PYRUVATE OXIDATION
Cleans up the two pyruvates for the citric acid cycle
• Start with 3 Carbons
• End with 2 Carbons and a coenzyme (Acetyl CoA)
• Produce 2 NADH + CO2
NAD+
NADH + H+
2
CoA
Pyruvate
Acetyl coenzyme A
1
CO2
3
Coenzyme A
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AEROBIC RESPIRATION ROAD MAP
Starts with glucose, end with ATP + CO2 + water + heat
CYTOSOL
MITOCHONDRION
2 NADH
Glycolysis
2
Pyruvate
Glucose
+2
ATP
by substrate-level
phosphorylation
2 NADH
Pyruvate
Oxidation
2 Acetyl
CoA
CO2
Citric Acid
Cycle
+2
ATP
by substrate-level
phosphorylation
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CITRIC ACID OR KREBS CYCLE
Operation: “Capture Electrons!”
• 6 steps • OXYGEN REQUIRED
• No energy investment necessary
finish
start
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CITRIC ACID OR KREBS CYCLE
Operation: “Capture Electrons”
• Step 1: Get rid of coenzyme and bond
with 4 C molecule to make 6C molecule
CoA
Acetyl CoA
CoA
2 carbons enter cycle
Oxaloacetate
1
Citrate
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CITRIC ACID OR KREBS CYCLE
Operation: “Capture Electrons”
• Step 2: Oxidize 6 C molecule to give NADH • CO2 is released
• Left with 5 C molecule
Citrate
NAD+
+ H+
NADH
2
CO2
leaves cycle
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CITRIC ACID OR KREBS CYCLE
Operation: “Capture Electrons”
• Step 3: Make an ATP by substrate‐level
phosphorylation
• CO2 is released
• More NADH is made
• Left with 4 C molecule
CO2
leaves cycle
3
NAD+
ADP +
P
NADH
+ H+
ATP
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CITRIC ACID OR KREBS CYCLE
Operation: “Capture Electrons”
•
•
•
•
Steps 4‐6:
More CO2, NADH
Release FADH2
Add water to re‐make 4C molecule we started with
start
Finish
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KREBS CYCLE Acetyl CoA
CoA
Operation: “Capture Electrons”
CoA
• Lots of redox reactions harvest electrons
• Starts and ends with oxaloacetate (4C molecule)
Citric Acid Cycle
2 CO2
3 NAD+
FADH2
3 NADH
FAD
+ 3 H+
ATP
ADP + P
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KREBS OR CITRIC ACID CYCLE
Takes place in mitochondria
•
•
2 ATP’s synthesized via substrate level phosphorylation
ATP
ATP
Acetyl CoA reacts with oxaloacetate and cycle renews oxaloacetate
• Oxygen required!
• Co2 given off
• 4 NAD+s reduced to NADH’s
• 2 FADs reduced to FADH2’s
= 12 electrons banked
FADH2
NADH
NADH
FADH2
NADH
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NADH
AEROBIC RESPIRATION
Electrons carried by NADH
Glycolysis
Glucose
Pyruvate
CYTOSOL
ATP
Pyruvate
Oxidation
Citric Acid
Cycle
FADH2
Oxidative
Phosphorylation
(Electron transport
and chemiosmosis)
MITOCHONDRION
Substrate-level
phosphorylation
ATP
Substrate-level
phosphorylation
ATP
Oxidative
phosphorylation
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OXIDATIVE PHOSPHORYLATION
Operation: “Make ATP”
OXIDATIVE PHOSPHORYLATION
Chemiosmosis generates energy to phosphorylate ATP
• Gradient of H+ ions create potential energy on the outside of the inner mitochondrial membrane (remember it has 2)
• ATP Synthase acts like a turbine or rotor
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CHEMIOSMOSIS
INTERMEMBRANE SPACE
H+
The process of making ATP from a Concentration gradient
Rotor
• The energy of H+ rushing in provides the energy to phosphorylate ADP to ATP
• Oxidative Phosphorylation rather than substrate‐
level phosphorylation
ADP
+
P
ATP
AEROBIC RESPIRATION
Oxidation of 1 glucose molecule
CYTOSOL
MITOCHONDRION
2 NADH
Glycolysis
2
Pyruvate
Glucose
6 NADH + 2 FADH2
2 NADH
Pyruvate
Oxidation
2 Acetyl
CoA
Oxidative
Phosphorylation
(electron transport
and chemiosmosis)
Citric Acid
Cycle
Maximum
per glucose:
O2
+2
ATP
by substrate-level
phosphorylation
CO2
H2O
+2
ATP
by substrate-level
phosphorylation
+ about
28 ATP
About
32 ATP
by oxidative
phosphorylation
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AEROBIC RESPIRATION
MANY steps result in products necessary to live
C6H12O6
6 O2
6 CO2
*Glucose
Oxygen
Carbon
dioxide
6 H2O
ATP
Heat
Water
*Glucose is the preferred molecule for respiration, but we can use 21
other types also
ATP FROM OTHER SOURCES
Food
Carbohydrates
Sugars
Fats
Proteins
Glycerol Fatty acids
Amino acids
Amino
groups
Glucose
G3P
Pyruvate
Glycolysis
Acetyl
CoA
Citric
Acid
Cycle
Oxidative
Phosphorylation
ATP
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THE BIGGER
PICTURE
Sunlight
energy
ECOSYSTEM
CO2 + H2O
Photosynthesis in
chloroplasts Organic
Cellular
respiration in
mitochondria
ATP
molecules
+ O2
ATP powers most
cellular work
Heat
energy
REQUIRED VIDEO & READING
Required Video!
“The Cellular Respiration Song”
Video links on website: Biosbcc.net/harrer
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TODAY’s CHECK‐IN (3pts)
Open Notebook & NOTHING ELSE!
**First try with no notes!
1. Draw a diagram showing the pathways of cellular respiration. Include glycolysis, pyruvate oxidation, the krebs cycle, oxidative phosphorylation and fermentation (2pts) .
2. Rate your understanding. Be honest. (1pt) A) Easy money, I totally get it!
B) I get the idea but the details are still a tad fuzzy.
C) This was hard, I should probably stop by for office hours to clarify.
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