47. Bioenergetics Flashcards
transfer and utilization of energy in biologic systems
bioenergetics
measure of change in heat content of the reactants and products
change in enthalpy
∆H
change in enthalpy is measured in
Joules (J)
measrue of change in randomness or disorder of reactants and products
change in entropy
∆S
- energy available to do work
* predicts the direction in which rxn will proceed
change in free energy (∆G)
∆G under standard conditions
reactants and products are 1 moar each
Temp is 25º or 298 K
Pressure is 1 atmosphere
Standard free energy change
∆G
∆G<0
exergonic
∆G> 0
endergonic
which rxn is spontaneous
exergonic
∆G0 of 2 consecutive rxns are additive
coupling rxns
acts as energy currency of the cells, transferring free energy derived from substances of higher energy potential to those of lower enery potential
Adenosine triphosphate
how is ATP produced
- substrate level phosphorylation
* oxidative phosphorylation
greatest quantitive source of high energy phosphate in aerobic organisms
oxidative phosphorylation
final substance to be reduced in oxidative phosphorylation
molecular O2
done through coupling rxns where phosphate group is transferred to ADP from another substance with higher ∆Gª
substrate level phosphorylation
