Bio CH 6 Energy/Metabolism
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Molecule reduced has higher energy
- oxidation/reduction or REDOX reactions
- Gains electron = reduction
- Loses electron = oxidation (reduction reactions)
always occur together because every electron that is lost through oxidation is gained by reduction.
"capacity to do work"
Free energy: energy available to do work in any system.
- Science of energy exchanges/changes
- measured by heat... kilocalore kcal
- 1 kcal = 1000 calories
- 1 calorie is the heat required to raise the temp. of water 1 degree Celsius
Energy can be in 1 or 2 states:
- 1) Kinectic: movement, motion
- 2) Potential: stored
1st law of thermodynamics:
Energy can be changed from 1 form to another, but not created or destroyed it can only change from one form to another (potential to kenetic). Total amount of energy in universe stays constant.
- Heat- Kinetic/potential
- Light- Kinectic
- Atomic energy- Potential
during each conversion energy is lost as heat.
2nd law of thermodynamics
In energy conversions the potential energy of the final stage will be less than that of the initial state (some energy given off (most as heat)
- Disorder in universe (entropy) is continously increasing.
- DISORDER MORE LIKELY THAN ORDER
Exergonic reactions: FIG. 4.6 and 6.5
Energy Given Off
Endergonic: FIG. 4.6 and 6.5
Requires energy. Must be coupled to exergonic one
Measure of disorder or randomness
C6H12O6 (glucose) ----> 6CO2 + 6H20 + energy in motochondria "catabolic reactions"
- H= heat content, potential energy, enthalpy
- ^H = change in H
- G= Gibbs free energy, available/usable energy
- T= Temperture
Usable energy is reduced due to increase in entropy
Involved in virtually all reactions (metabolism)
Enzyme synthetic reactions
endergonic 'take in energy'
Enzyme breakdown reactions
exergonic 'give off energy'
- globular protein made of 1 or more chains
- -Primary, Secondary, Tertiary, Quat. Structures
Active Site and Substrate Molecules (FIG 6.8)
Speed of Enzymes
1000 substrates molecules per second
Enzymes are acting as catalysts (speed up reactions, not used up)
BIO CATALYST SPECIFIC
Regulation/ Control of Enzymes
- 1) production of enzyme
- 2) some enymes have control site (allosterksite)
- -End Point
- 3)Substrate of molecule availble?
- 4) "cofactors" available
- 5) pH correct? optimum pH
- 6) Temp. correct
- Molecules that help enzymes (carry electrons)
- 1) some are organic (coenzmes)
- -vitamins/coenzymes B6,B12 (electron carriers)
- 2) inorganic molecules
- -some are free in cytoplasm / or attached
- -some are single / or in groups
Are there any non-protein (non-enzymes catalyst?
YES - RNA (ribozymes) help reactions
- Energy Currency Molecule
- -endergonic reaction: J & K ----> L
- J,K,L = compounds
- J&K need enrergy of 10kcal/mol
- this reaction neds to be coupled to exorganig reaction
- ATP -----> ADP + P (phosphours group)
- -7.3kcal/mole released
needs 10kcal but only has 7.3 so need 2 ATP's to get to 10
ATP is constantly being made and used.
Origin of specifin biochemical pathway:
- 1st organism (cells) -used organic molecules in H20 around them
- Example: R=simple comound, if R begins to run short selection for cell who could help make R begins =T+S....if T begins to run short...F+G is found to help (works backwards)
F+G ---> (T)+S----> R
Gibbs Free Energy
^G = ^H-^T^S
- G= gibbs free energy, available energy
- T= Temp
- S= Entropy
Part of enzyme away from active site, on/off switch
Region of enzyme surface, substrates bind, lowering activation energy required and fascilitates function.
Control mechanism, concentratration inhibits sythesis
Substance binds to enzyme and decreases its activity
Binds to enzyme and increases activity
Graph of Reactants/Products: Endergonic/Exergonic
- Endergonic- Products contain more energy than reactants
- Exergonic- products contain less energy than reactants
Catalysts and activation graph:
lowers activation energy needed to initiate reaction (enzymes act as catlysts)
Amount of energy required to break or form chemical bond:
Excess energy released as:
Structure of ATP:
- 1.) 5 Carbon Sugar ribose
- 2.) 2 carbon nitrogen
- 3.) chain of three phosphates
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