Coenzyme NAD+ is an electron carrier NAD + - oxidized NADH + H
+ - reduced
Slide 5
NADH -Nicotinamide adenine dinucleotide Coenzyme found in all
cells Made of 2 nucleotides
Slide 6
Slide 7
Mitochondrial structure - label
Slide 8
Mitochondrial structure
Slide 9
Cellular Respiration overview Process Starting Molecule End
product LocationSubstrate level phosphor ylation Energy shuttled to
oxidative phosphor ylation Glycolysis1 glucose2 pyruvate Cytosol2
ATP2 NADH (intermed iate step) 2 pyruvate 2 Acetyl Co-A, 2 CO 2
Matrix of mitochon dria None2 NADH
Slide 10
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Totals entering oxidative phosphorylation: 4 ATP from substrate
phosphorylation 10 NADH (2 from glycolysis) 2 FADH 2
Slide 12
NADH from glycolysis 2 ATP (need 1 to shuttle NADH into
mitochondria) NADH 3 ATP FADH 2 2 ATP This is theoretical yield
Total energy produced = 36 38 ATP molecules - 2 in glycolysis, 2 in
Krebs, 32-34* in Oxidative phosphorylation * 34 for plants (dont
spend an ATP to get NADH into mitochondria), 32 for animals
Slide 13
Glycolysis Glyco glucoseLysis - splitting or breaking Pg.
162-163 How is glucose split?
Slide 14
Glycolysis summary How many reactions are required? What
catalyzes each reaction? How many ATP are produced? How many net
ATP are produced? What is the initial reactant? What are the final
products? Where does this occur in the cell?
Slide 15
Glycolysis
Slide 16
Glycolysis summary How many reactions are required? 10 What
catalyzes each reaction? Specific enzyme How many ATP are produced?
4 How many net ATP are produced? 2 What is the initial reactant?
glucose What are the final products? Pyruvate, 2 ATP, 2 NADH Where
does this occur in the cell? cytosol
Slide 17
Krebs cycle (aka citric acid cycle) What is the starting
molecules for the Krebs cycle? What was the ending molecules of
glycolysis?
Slide 18
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Krebs cycle (aka citric acid cycle) What is the starting
molecules for the Krebs cycle? Acetyl CoA What was the ending
molecules of glycolysis? pyruvate
Slide 20
Pyruvate to Acetyl CoA Intermediate step: pyruvate oxidation
How many reactions needed to convert pyruvate to acetyl CoA? What
is lost in the process? What is gained in the process? Where does
this occur?
Slide 21
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Pyruvate to Acetyl CoA Intermediate step: pyruvate oxidation
How many reactions needed to convert pyruvate to acetyl CoA? 3 What
is lost in the process? CO 2, electron to NAD+ What is gained in
the process? NADH, Acetyl CoA Where does this occur? As pyruvate
enters mitochondrion, in the mitochondrial matrix
Slide 23
Krebs Cycle 1 st step In first step: Oxaloacetate (4 C) +
Acetyl-CoA (2 C) yields citrate (6 C) Oxaloacetate gets regenerated
through Krebs cycle -ate conjugate bases of the organic acids
Carboxyl groups can donate protons i.e. citrate is the conjugate
base of citric acid
Slide 24
Krebs cycle p. 165 How many reactions? What catalyzes these
reactions? How many ATP produced? How are the ATP produced? Where
does the rest of the energy harvested go?
Slide 25
Krebs Cycle
Slide 26
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Krebs cycle How many reactions? 8 What catalyzes these
reactions? Specific enzymes How many ATP produced? 1 per cycle (2
total) How are the ATP produced? Substrate phosphorylation Where
does the rest of the energy harvested go? Electron carriers: 3
NADH, 1 FADH 2 per cycle (6 NADH, 2FADH 2 total)
Slide 28
Krebs cycle How many turns of the cycle for 1 molecule glucose?
What are the initial reactants? Final products? Where does this
occur?
Slide 29
Krebs cycle How many turns of the cycle for 1 molecule glucose?
2 since glucose splits into 2 pyruvate What are the initial
reactants? Final products? Initial: 2 Acetyl CoA, 6 NAD+, 2 FAD, 2
ADP Final: 4 CO 2, 6 NADH, 2FADH 2, 2 ATP Where does this occur? In
the mitochondrial matrix
Slide 30
Substrate level phosphorylation
Slide 31
Substrate Level Phosphorylation As each bond of glucose is
broken, energy is released: If enough energy released all at once,
the energy is used to directly phosphorylate ADP to make ATP
(substrate level phosphorylation)
Slide 32
-- If amount of energy released is small, electrons are taken
off as units of energy and handed to an electron shuttle, NADH NADH
gathers all the electrons and passes them off to the electron
transport chain, so they can make ATP through oxidative
phosphorylation
Slide 33
Oxidative Phosphorylation: Electron Transport Chain &
Chemiosmosis Electron Transport Chain see diagram on handout Where
do the electrons for the electron transport chain come from? Why
are electrons transferred from carrier to carrier? Why does FADH 2
enter at a different point than NADH?
Slide 34
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Electron Transport Chain/Oxidative Phosphorylation Electron
Transport Chain see diagram on handout Where do the electrons for
the electron transport chain come from? From glycolysis,
intermediate, krebs Why are electrons transferred from carrier to
carrier? Transferred to more electronegative carrier Why does FADH
2 enter at a different point than NADH? Has higher
electronegativity
Slide 36
What atom is the final acceptor of the electron? Why? What does
it form? What is gained during this process?
Slide 37
What atom is the final acceptor of the electron? oxygen Why?
Most electronegative What does it form? water What is gained during
this process? A H+ gradient
Slide 38
Oxidative phosphorylation What is the purpose? What is a
chemiosmotic gradient? How does this generate ATP?
Slide 39
Oxidative phosphorylation What is the purpose? To produce ATP
from ADP What is a chemiosmotic gradient? A difference in
concentration of H+ ions across a membrane (can be used to do work)
How does this generate ATP? Flow of H+ ions through ATP synthase
into mitochondrial matrix cause the ATP synthase to rotate-
chemical energy converted to mechanical energy This drives
phosphorylation of ADP into ATP (ADP + inorganic phosphate)
Slide 40
ATP Synthase Uses flow of hydrogen ions down gradient to form
ATP from inorganic phosphate and ADP
Slide 41
ATP synthase video http://www.dnatube.com/video/104/ATP-
synthase-structure-and-mechanism
http://www.dnatube.com/video/104/ATP-
synthase-structure-and-mechanism
Slide 42
Cellular Respiration
Slide 43
ATP Numbers... Not exact Based on experimental data- 1 molecule
glucose yields 29 ATP NADH 2.5 ATP, FADH 2 1.5 ATP NADH from
glycolysis in cytosol electrons get passed to NAD+ or FAD in
mitochondrial matrix (which carrier makes a difference in total
ATP) Also some of the proton motive force powers mitochondrions
uptake of pyruvate from cytosol, also transport of phosphate into
mit. matrix
Slide 44
Cellular respiration efficiency about 40% of energy from
glucose gets stored in ATP The rest of the energy is lost as
heat
Slide 45
Thermoregulation Reducing efficiency of cellular respiration
Hibernating mammals need to maintain body temperature Have a
channel protein in inner mitochondrial membrane that allows protons
to flow back down concentration gradient without generating ATP
Allows for oxidation of fats to generate heat without ATP
production
Slide 46
If oxygen is not present, etc and oxidative phosphorylation
cant occur 2 ways to produce ATP: Anaerobic respiration prokaryotic
organisms in environment without oxygen Use another final electron
acceptor rather than oxygen, i.e. sulfur Fermentation ATP without
oxygen
Slide 47
Makes ATP through glycolysis (only 2 ATP) NADH transfers its
electrons to pyruvate, so NAD+ can be used again in glycolysis
Alcoholic fermentation pyruvate converted to ethyl alcohol and CO 2
Lactic acid fermentation pyruvate converted to lactate
Fermentation
Slide 48
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What about prokaryotes? Glycolysis cytosol Krebs cycle cytosol
Electron transport chain electron carriers in plasma membrane,
gradient gets generated across plasma membrane Do not need to
transport electrons (in NADH) from glycolysis into mitochondria, so
can get more ATP
Slide 50
Evolution & Glycolysis Glycolysis is widespread among
organisms Oldest fossils of bacteria 3.5 billion years old O 2 in
atmosphere not until 2.7 billion years ago Perhaps early cells got
ATP just through glycolysis
Slide 51
Food Catabolism Proteins, Carbohydrates & Fats can all be
used by cellular respiration to make ATP Biosynthesis Intermediates
in the pathway of cell. resp. can be used to synthesize molecules
for the cell.
Slide 52
Control of cellular respiration Phosphofructokinase Enzyme that
catalyzes 3 rd step of glycolysis - commitment step for glycolysis
Allosteric enzyme Inhibited by ATP, citrate Stimulated by AMP
