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Cellular Respiration
Ch 7 pp.145-155
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Energy From ElectronsAtom nucleus
PositiveAttracts/pulls electronsPotential energy released when nucleus pulls electrons to it (makes bond)
Think of the atomic structure of the following atomsOxygen (make up the oxygen molecule in cell resp)Hydrogen and Carbon (bonded to each other in glucose)Which has a stronger attraction for electrons?What happens in cell respiration?
Oxygen molecule reacts with glucoseCarbon and hydrogen leave each other and become bonded to oxygen's,creating the carbon dioxide and water produced in cellular respiration
The electrons in hydrogen and carbon are pulled toward the nucleus of theoxygen atoms, thus releasing potential energyOccurs when you burn sugar, lots of energy released almostinstantaneouslyIn cellular respiration, occurs in controlled steps to prevent a massiverelease of energy
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Electron Transport Chain (etc)Cell respiration releases E in small amounts in the form of ATP moleculesSeveral stepsOxygen is only involved in the end
Electrons=energyElectrons are carried by electron carrier moleculesElectron carrier is a molecule that can accept a pair of high-E electronsand transfer them along with most of their energy to another molecule
Oxygen is the final electron acceptor that joins withhydrogen ions to make water
This transfer of electrons throughout cellular respiration iscalled the electron transport chain (ETC)For every transfer of electrons between molecules in thechain, a little E is released
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Cellular RespirationA cellular process (part of metabolism)Metabolism
Set of chem. rxns through which an organismbuilds up or breaks down materials as it carriesout lifes processes
C6H12 O6 (aq) + 6O 2 (g) 6CO 2 (g) + 6H 2O (l) Glucose reacts with oxygen to produce carbondioxide and water
REQUIRES OXYGENAerobic
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Cellular Respiration: 3 parts1. Glycolysis
cytoplasm
1. Krebs CycleMitochondrianmatrix
1. Electron TransportChain
Within the innermitochondrialmembran
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GlucoseGlycolysis
Cytoplasm
Pyruvicacid
Electrons carried in NADH
KrebsCycle
Electronscarried in
NADH andFADH 2 Electron
TransportChain
Mitochondrion
Mitochondrion
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Glucose(C 6H12 0 6)
+Oxygen
(0 2)
Glycolysis KrebsCycle
ElectronTransport
Chain
Carbon
Dioxide(CO 2)
+Water (H2O)
Cellular Respiration
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GlycolysisGreek word glukus sweetLatin word lysis loosening or decomposingDef: the process in which one molecule of glucose is broken in half,producing two molecules of pyruvic acid (a three-carbon compound)Takes place outside mitochondria, in cytoplasm of cell
Energy releasing processDoes NOT require oxygenRequires an investment of 2 ATP molecules at beginning to get it going
These 2 atps are like an investment that pays back with interestIn order to earn money from a bank, you have to put $$ in
4 molecules of ATP produced at the end of Glycolysis
What is the net gain?2 ATPs
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NADH production4 high-E e- are removed and passed to twoelectron carriers called NAD+ (nicotinamideadenine dinucleotide) (each NAD+ carries 2 e-)
Each NAD+ molecule accepts a pair of high-Ee-Once e- are accepted, NAD+ becomes NADH,which will transfer e- to other molecules
NAD+ helps pass energy from glucose to otherpathways in the cell
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GlycolysisGlucose, a six-carbon sugar, receives 2 phosphates from the first 2ATPs invested in GlycolysisGlucose now becomes fructose 1,6-biphosphate (highly energized)Fructose 1,6-biphosphate splits to become two molecules of CCC-P(glyceraldehyde 3-P)Each of these molecules transfers electrons and hydrogen ions toNAD+ molecules that come inAccepting two e- and hydrogen ion changes NAD+ to NADH, whichcarry electrons to the next part of GlycolysisAn inorganic phosphate is added to the CCC-P molecule changing itto P-CCC-P (1,3-biphosphoglycerate)2 ADP molecules will come in and snatch off the phosphates from P-CCC-P and the molecule has now become PYRUVATE or PYRUVICACIDPyruvate is then sent on to the next phase, the Krebs Cycle
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Reactants and Products of Glycolysis
In1 glucose2 ATP2 NAD+
Out2 NADH (to ETC)4 ATP2 Pyruvates (to Krebs cycle)(Net ATPs 2)
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Glucose
To the electrontransport chain
2 Pyruvic acid