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27 Cards in this Set
- Front
- Back
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metabolism
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controlled biochem rxns
function:repduce organism reproduction requires work which requires energy. energy is capacity to do work G=free energy, released to do useful work |
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Free energy
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pH 7 and initial [] of all reactants at 1M
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delta G fromation of compounds
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A + B-->C + D....G(o)
G(o)f[C + D] - G(o)f[A + B] where G(o)f is the free energy of formation of a compound free from its elements |
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delta G with biological compounds
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glucose -917.3
CO2 -394.4 acetate -369.4 water -237.2 |
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enzymes
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metabolic rxns are spontaneous
enzymes are organic catalysts heme has prosthetic group apoenzyme:enzyme proteins that function with coenzymes(vit,NAD,FAD) are intermediate carrier reactants and loosely bound. [entire complex is holoenzyme] |
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components of enzymes
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cofactor:Fe,Mg,Zn,Cu
active site coenzyme prosthetic group apoenzyme |
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enzyme activity
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substrate binds and induces change, interaction bw substrate and chemical groups, activates for chem rxn.
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enzymes and Ea
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enzymes lower Ea
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catalytic cycle of enzymes
fructose 1,6 biphosphate aldolase |
the substrate is that
enzyme changes conformation and puts strain on substrate pdts:glyceraldhyde,dihydroxyactetone |
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categories of enzymes, with mode of action
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hydro:hydrolytic rxns
isomer:rearrange molecules polymer/lig:link subunits or macromolecules ly:link molecules, no polymer oxidoreduct:redox transfer:transfers groups |
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redox rxns
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reduction:add e-
oxidation:remove e- e-'s cant exist alone in soln for every ox is a reduct |
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redox couples
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oxidation(H2 gas),release e-
H2-->2e- + 2H reduction(oxidation of H2) is coupled to the reduction of many diff compounds |
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reduction potentials
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vary in redox potentials
E(o)':reduction potential measured electricaly and expressed in volts, expressed in 1/2 rxns written as reduction rxns. 1/2O2 +2H +2e- -->H2O E(O)'=+.816 2H + 2e- --->H2 E(o)'=-.421 |
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redox couples (refer to previous rxns)
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the oxidized form is always placed on the left.
arranged from strongest reductants(-E(o)') to the strongest oxidants (+E(o)') in the so called e- tower |
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electron tower
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E(o)'(-.5)----->(+.9)
+.9 has MORE neg delta G than -.5!!! |
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the electron tower
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1.oxygen at the bottom the most favorable electron acceptor
2.middle:acceptor or donor (most are anaerobic) *anoxic conditions and in the presence of H2, fumarate can be a donor.Presence of NO3 succinate can be donor |
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redox electron carriers
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catabolism:donor is called an energy source(glu,H2S,succ)
initial e- donor is the primary and final acceptor is the terminal e- acceptor. |
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electron carriers into 2 classes
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freely diffusible:NAD, NADP
firmly attached to mem proteins:FMN,FAD,heme |
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soluable electron carriers
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2 e- and 1 proton accepted, the proton is diffusible.
reduced forms are indicated simply as NADH and NADPH |
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NAD cycling
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1.enzyme with substrate(donor) and is oxidized to NAD
2.enzyme with substrate(acceptor) and reduced to NADH |
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NAD/NADH
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involved directly in energy-generating (catabolic) rxns
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NADP/NADPH
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primarily involved in the biosynthetic(anabolic) rxns
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conservation of energy released by redox rxns
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1.energy released is conserved for immediate use mainly as high energy phosphate bonds.
2.ATP is present in relatively low []'s and is cleaved to ADP +Pi to drive endergonic rxns. Re-synthesized from ADP + Pi with energy gained from redox rxns. |
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high energy compounds
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phophoenolpyruvate -51.6
1,3 biphosphoglycerate -52 ATP -31.8 ADP -31.8 |
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low energy compounds
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AMP -14.2
glucose 6-phosphate -13.8 |
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long term energy storage
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ATP and other low mw, high energy compounds, broken for anabolic rxns, regenerated for catabolic.
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energy storage compounds
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1.starch/glycogen
2.polyhydroxyl alkanoates 3.elemental S:chemolithotrophs |
