Download Cellular Respiration

Giving you the energy you need!
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Use your dominant hand
Open and close the pin (with your thumb and
forefinger) as many times as you can for 20
seconds while holding the other fingers
straight out!
Repeat for 5 more continuous trials!
Repeat for the non-dominant hand
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What happened as time went on?
How did you hands feel at the end?
Was there a difference in dom and non-dom
hands?
Why will your muscles recover in about 10
min?
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The total amount of energy in the universe is
constant!
Energy cannot be created or destroyed but
only converted to one form into another!
Activation Energy – Amount of E required to
break chemical bonds
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Universe favours entropy
(pg. 63-64)
 Randomness and chaos
 Smaller, more stable molecules
 Even distribution of matter and energy
 Blame your messy room on entropy!
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In all reactions, energy and entropy are both
involved!
◦ Net increase in entropy in the universe
Is it possible?
◦ see text pg. 6, Table 2
◦ pg. 92, paragraph 1.
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Energy capable of doing
work.
◦ In this case: Chemical energy
◦  potential energy stored in
chemical bonds
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Free energy of products more than reactants
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Ex: Photosynthesis
◦ Light energy converted to stored chemical energy in
C6H12O6
◦ Every molecule of glucose contains 2870kJ
Photosynthesis
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Free energy of products is less than reactants
Free energy is released from the reactants - increasing entropy!
Ex: Cellular respiration
◦ Free energy stored in the bonds of glucose is
released and then trapped and stored in the bonds
of ATP (at a controlled rate)!
Cellular Respiration
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Goal: to create ATP using released energy from
glucose!
 See handout
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Four main parts...
1)
2)
3)
4)
(occuring in)
Glycolysis (cytoplasm)
Pyruvate Oxidation (mitochondrial matrix)
Krebs Cycle/Citric Acid Cycle (mitochondrial matrix)
Electron Transport Chain (inner mitochondrial membrane)
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Redox Reactions
Phosphorylation
(reduction-oxidation)
◦ Substrate Level Phosphorylation
 (during glycolysis and the Krebs cycle)
◦ Oxidative Phosphorylation
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These reactions occur throughout the cellular
respiration pathways
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Energy metabolism in cells involves oxidation
reactions.
Oxidation involves the transfer of an electron
from a molecule, which is said to be
oxidized, to another molecule, which is said
to be reduced.
An oxidation cannot occur without a
corresponding reduction. They are PAIRED
reactions.
Many important redox reactions in cells
require the presence of coenzymes.
The redox reactions of cellular respiration
commonly involve the following coenzymes:
1) NAD: Nicotinamide adenine dinucleotide
NAD+ + 2 e- + 2 H+ → NADH + H+
*the second H+ dissolves into cytosol *
2) FAD: Flavin adenine dinucleotide
FAD + 2e- + 2 H+ → FADH2
LEO the lion says GER
 Lose
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Electrons
 Oxidized!
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SAYS...
 Gain
Electrons
 Reduced!
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“Reduced” means that the overall positive
charge of the molecule has decreased (due to
accepting the electons!)
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A mechanism forming ATP directly in an
enzyme-catalyzed reaction
ATPase
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ADP + Pi + 31 kJ/mole
ATP
This is called Phosphorylation...
The opposite is Dephosphorylation
A single muscle cell uses 600 million ATP per minute
The body consumes its own mass in ATP per day via constant
recycling!
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A glucose is broken down into 2 Pyruvate
molecules
Brief overview...
http://highered.mcgrawhill.com/sites/0072507470/student_view0/c
hapter25/animation__how_glycolysis_works.h
tml
Occurs in the cytoplasm
Anaerobic (doesn’t need oxygen!)
See handout!! And pg. 98
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Free energy?
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Endergonic?
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Exergonic?
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Phosphorylation? Substrate-level?
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REDOX reaction memory aid?
Anaerobic vs aerobic?
Four stages in aerobic respiration?
Glycolysis reactant?
Glycolysis products?
Energy carriers?
Source: Pearson Education
glucose
Glycolysis
ATP
Hexokinase
ADP
glucose-6-phosphate
Phosphoglucose Isomerase
6-Carbon
Change
in
isomer
fructose-6-phosphate
ATP
Phosphofructokinase
ADP
fructose-1,6-bisphosphate
Aldolase
(G3P)
3-Carbon
(x2)
(DHAP)
glyceraldehyde-3-phosphate + dihydroxyacetone-phosphate
Triosephosphate
Isomerase
Glycolysis continued
glyceraldehyde-3-phosphate
NAD+ + Pi
Glyceraldehyde-3-phosphate
Dehydrogenase
NADH + H+
Glycolysis
cont.
Recall
that there
are 2 G3P
per
glucose.
1,3-bisphosphoglycerate
ADP
Phosphoglycerate Kinase
ATP
3-phosphoglycerate
Phosphoglycerate Mutase
2-phosphoglycerate
Enolase
H2O
phosphoenolpyruvate
ADP
Pyruvate Kinase
ATP
pyruvate
Balance sheet of ATP chemical bond energy:
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Bonds broken/energy used:
2
How many ATP are converted to ADP? ______
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Bonds formed/energy acquired:
How many ATP are formed from ADP?
(Remember there are two 3C fragments
4
from glucose.) ________
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2
Net energy gain (#ATP formed) per glucose: ________
Reactants:
Products:
Glucose + 2 ADP + 2 Pi + 2 NAD+
2 Pyruvate+2H+ 2 ATP + 2 NADH
***For more detail on each step see pg. 98 or watch this
http://www.youtube.com/watch?v=O5eMW4b29rg&feature=related
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Efficiency: 2.2%
◦ Percentage of the total free energy in glucose that
is harnessed as ATP during Glycolysis
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Not good enough.
So the Krebs Cycle and electron transport
chain continue to process the pyruvate
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http://www.youtube.com/watch?v=EfGlznwfu
9U
HW: Page 115 #1-6
Source: Pearson Education
Source: Pearson Education
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Occurs in the mitochondrial matrix
General Equation...
(CoA = coenzyme A)
2 Pyruvate + 2 CoA + 2 NAD+
2 acetylCoA +2CO2 + 2 NADH + 2H+
**Acetyl CoA = 2-carbon molecule
(other C was lost in CO2)
- becomes a reactant for the Krebs Cycle!!
Source: Pearson Education
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Occurs in the mitochondrial matrix
Many enzymes, coenzymes and other
molecules organized on the inner membrane.
Overview...
http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/anima
tion__how_the_krebs_cycle_works__quiz_1_.html
phosphoenolpyruvate
http://www.daviddarling.info/encyclopedia/C/citric_acid_cycle.html
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http://www.purposegames.com/game/0e38f
b1b/info
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By the end of step 4 of the Krebs Cycle the
entire glucose molecule is consumed.
All 6 carbon atoms are lost as CO2 along the
way (3 per pyruvate)
Products? 3 CO2, 2 ATP, 6 NADH, 2 FADH2
More depth! : pg. 102 of textbook
http://www.youtube.com/watch?v=A1DjTM1qnPM
Note where H2O is used and CO2 is released!
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NET HARNESSED ENERGY
 4 ATP (2 Glycolysis, 2 Krebs)
 12 reduced coenzymes:
 2 NADH (Glycolysis)
 2 NADH (Pyruvate Oxidation stage)
 6 NADH (Krebs)
 2FADH2 (Krebs)