Daily Warm-up Friday, October 10th
Describe the Kreb’s Cycle and oxidative
phosphorylation. How many ATP are
produced in each?
HW:
-Read 7.5 and finish cell respiration project
Turn in:
-Nothing
AP Biology
Today’s Task
 Create a representation of cellular
respiration in your own words
Prezi
 Comic strip
 Story

 15 points
 Need glycolysis, Kreb’s Cycle, oxidative
phosphorylation and their details.
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Peep video
Bioflix video on cell respiration
Cell respiration video
http://www.youtube.com/watch?
v=3aZrkdzrd04
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Cellular Respiration and
Fermentation
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Remember energy coupling?
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Yielding Energy
 Catabolic processes in the cell
 Anaerobic respiration
 Aerobic respiration
 Both of these comprise cellular
respiration
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How do we harvest energy from fuels?
 Digest large molecules into smaller ones

break bonds & move electrons from one
molecule to another
 as electrons move they “carry energy” with them
loses e-
gains e-
+
oxidized
reduced
+
+
e-
oxidation
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–
e-
reduction
e-
redox
How do we move electrons in biology?
 Moving electrons in living systems

electrons cannot move alone in cells
 electrons move as part of H atom
loses e-
gains e-
oxidized
+
+
oxidation
e
p
reduced
+
–
H
reduction
H
oxidation
C6H12O6 +
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H e-
6O2
 6CO2 + 6H2O + ATP
reduction
Oxidation & reduction
 Oxidation
 Reduction
adding O
 removing H
 loss of electrons
 releases energy
 exergonic

removing O
 adding H
 gain of electrons
 stores energy
 endergonic

oxidation
C6H12O6 +
6O2
 6CO2 + 6H2O + ATP
reduction
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like $$
in the bank
Moving electrons in respiration
 Electron carriers move electrons by
shuttling H atoms around
 NAD+  NADH (reduced)
 FAD+2  FADH2 (reduced)
NAD+
nicotinamide
Vitamin B3
niacin
O–
O– P
O
–O
NADH
O
H
C
H
–O
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reduction
oxidation
adenine
ribose sugar
O
C
phosphates
O–
O– P
O
H H
NH2
N+
+
reducing power!
carries electrons as
a reduced molecule
N+
O–
O– P
O
–O
O–
O– P
O
–O
NH
How efficient!
Build once,
use many ways
Metabolism is tightly controlled
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Overview of Cellular Respiration
 3 metabolic stages

Anaerobic respiration
1. Glycolysis
 respiration without O2
 in cytosol

Aerobic respiration
 respiration using O2
 in mitochondria
2. Krebs cycle
3. Electron transport chain
C H O6 +
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6 12
6O2
 ATP + 6H2O + 6CO2 (+ heat)
Step 1: Glycolysis
 Glucose (6C) is cleaved into 2
molecules of pyruvate (3C)
 Requires 2 ATP but produces 4 ATP
 2 NAD+ are reduced to 2 NADH
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Glycolysis and Evolution
 Core process shared by all domains
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Next Step
 Anaerobic conditions- Fermentation

Makes 2 ATP
 Aerobic conditions
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Citric Acid Cycle aka Kreb’s Cycle
Step II: Citric Acid Cycle
 Inner membrane of mitochondrion
 Pyruvate becomes acetyl CoA
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Step III: Oxidative Phosphorylation
 2 steps

Electron Transport Chain
 Transfer of electrons
 Proteins embedded in
membrane
 Last transfer is to oxygen
 No ATP

Chemiosmosis
 ATP synthase
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Fermentation
 Anaerobic respiration

Electron transport chain does not use
oxygen
 Fermentation
Extension of glycolysis
 Must recycle NADH back to NAD+

 Done by transferring electrons to pyruvate
(end product)
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Two Types of Fermentation
 Alcohol Fermentation
Pyruvate converted to ethyl alcohol
 CO2 produced

 Bacteria and yeast
 Lactic acid Fermentation

Pyruvate reduced directly by NADH to
form lactic acid
 Fungi and bacteria
 Cheese
 Human muscle cells…
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