Ch 5 Flashcards
types of cellular work
synthetic, mechanical, concentration, electrical, heat generation, light generation
phototrophs
use light energy
chemotrophs
obtain energy through chemical bond oxidation
oxidation
removal of e- (releases energy)
reduction
addition of e- (requires energy input)
internal energy (E)
total energy stored within a system
delta E
E products - E reactants
H
change in enthalpy; heat content
exothermic
when delta H is negative (energy released)
endothermic
when delta H is positive (energy absorbed)
thermodynamic spontaneity
measure of whether or not a rxn or process can occur
directionality
rxns can only spontaneously proceed in one direction
free energy (G)
measure of spontaneity for a system alone
exergonic rxns
energy-yielding (spontaneous)
endergonic rxns
energy-requiring (not spontaneous)
equilibrium constant (Keq)
ratio of product concentration to reactant concentration at equilibrium
delta G tells us…
- if a rxn is thermodynamically possible
- how much free energy would be liberated
delta G does not tell us…
rxn rate or mechanism
standard state
25 degrees C (298 K), 1 atm, product and reactant concentrations at 1M
standard RT
592 cal/mol
steady state
state of cellular activity maintained in order for cells to stay alive (cells in equilibrium are dead)
