Lecture 3 Flashcards
(23 cards)
closed system
energy exchange allowed between system and surroundings. Not matter.
isolated system
no exchange of energy or matter
first law of thermodynamics
Energy is conserved
state function
depends only on present state. not how it got there. ie. glucose. multiple methods of preparation but glucose is always equal.
delta E = ? + w
q + w
heat absorbed by the system
q
work done by the system
w
value of q when energy flows into the system
positive
value of w when energy flows into the system
positive
sign of delta H for exoothermic process
negative
second law of thermodynamics
system tends toward disorder. increased entropy.
third law of thermodynamics
entropy is zero at 0 K but reaching 0 K is impossible
a measure of the spontaneity of a process under conditions of constant temperature and pressure
free energy change delta G (a state function)
what does delta G represent in biological systems
maximum possible amount of useful energy obtainable form a reaction
when delta G is zero
rexn at equilibrium
exergonic
releases energy
delta G less than zero means
reaction favors products or folding. releases energy and/or heat
two driving forces of reaction
decreased enthalpy or increased entropy
sign of delta S for a decrease in order
positive
hydrolysis of ATP relieves ___ repulsion
electrostatic
transfer potential of ATP
-30.5 kJ/mol
activation energy of ATP
> 200 kJ/mol
read DSC article for EC
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