ap biology - cellular respiration
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Cellular RespirationCellular RespirationChapter 9
Cellular Cellular RespirationRespiration
C6H12O6 + O2 CO2 + H2O + energy
–ΔG (exergonic)MitochondriaSeries of redox
reactions
Oxidation / ReductionOxidation / ReductionWhen electrons are transferred to oxygen
(very electronegative), they release energy that the cell can use
Important Respiration TermsImportant Respiration TermsNAD+ (nicotinamide
adenide dinucleotide): coenzyme electron acceptor
NAD+ becomes NADHElectron transport
chain
Steps of RespirationSteps of RespirationGlycolysis: cytoplasmCitric Acid Cycle: mitochondrial matrixOxidative
Phosphorylation:Innermembrane
GlycolysisGlycolysis
2 ATP usedGlucose split into 2
pyruvate (and 2 H2O)4 ATP, 2 NADH
produced(no matter presence of
O2)
Before the Citric Acid CycleBefore the Citric Acid CyclePyruvate and O2 enter mitochondriaPyruvate converted to acetyl CoA
◦ COO- released as CO2◦ NADH created◦ CoA added (unstable)
Krebs / C.A. CycleKrebs / C.A. CycleProduces NADH,
FADH2 and ATP
http://encyclopedia.kids.net.au/page/ci/Citric_acid_cycle
In Out
Acetyl-CoA CoA
2 CO2
H2O
3 NAD+ 3 NADH
ADP + Pi ATP
FAD FADH2
Electron Transport ChainElectron Transport ChainNADH donates
electronsPassed down to
more electronegative proteins (releasing a little energy each time)
Electron Transport ChainElectron Transport ChainTransports H+ to inner membrane spaceO2 final electron acceptor H2O
ATP SynthaseATP SynthaseEnzyme along inner mitochondrial membraneUses electrochemical potential energy to drive
phosphorylationProton-motive force
Accounting for ATPAccounting for ATPInaccurate due to unknowns: # of H+
needed, transport method, etc.Max of 38 ATP per glucose
Fermentation
FermentationOxygen necessary as final electron
acceptorTransfers electrons from NADH to
pyruvate allowing glycolysis to continue
Alcoholic FermentationPyruvate releases CO2
Resulting compound reduced by NADH to ethanol
Bacteria
Lactic Acid FermentationPyruvate reduced by NADH to lactate
Animals, fungi, and bacteria
Buildup causes muscle fatigue (ATP use outpaces O2 supply)
Comparing Respiration and Fermentation
Without O2, energy in pyruvate not used in E.T.C.
Only 2 ATP produced per glucose
Test Monday 10/19/09Chapter 8 (all)Chapter 9 (all)
◦Read 9.6 (pg. 176-178) on your own.
Quiz on Photosynthesis (Chapter 10) online. Take by Tuesday at 9 am.
Lab Friday. (Might take more than one period)
Self-Quiz Question 1 (from text)During the redox reaction in
glycolysis, which compound is reduced? Oxidized?
Self-Quiz Question 2Explain the transfers of energy
that occurs during both the citric acid cycle and the electron transport chain.
Self-Quiz Question 3A glucose-fed yeast cell is moved
from an aerobic environment to an anaerobic one. For the cell to continue using and generating ATP at the same rate, what how would its glucose consumption change?
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