bioenergetics Flashcards
the equilibrium constant equation (Keq)
[products eq] / [reactant eq]
change in G equation
-RT ln (Keq)
when Keq is greater then 1 (more products than reactants) delta G is
negative
when Keq equals 1 (same number of products and reactants) delta G is
0
equilibrium does not mean that the concentration of ___ and ____ are equal
products and reactants
delta g tells you how ____ are the products relative to reactants
stable
the delta g also tells you the ___ of products to reacts if a reaction reaches equilibrium
ratio
delta G is what you use under non standard conditions what is used for standard conditons
delta G’°
delta G = delta G’° + RT ln(G) ; when is this equation used
under non standard conditions
Q is what
reaction quotient
if a reaction is at equilibrium Q= and delta G is
Keq; 0
if the reaction goes to the left to form more reactants then Q__ Keq and delta G is ___ 0
> ; >
if the reaction goes to the right to form more products then Q ___ Keq and delta G __ 0
< ; <
can a reaction proceed is delta G is greater then 0
yes
what do we have to make sure of to allow a reaction to overcome delta G > 0
products have to be much less than reactants (product removal; making B make something else is a fast way to do this)
metabolism is all about “coupling” favorable reactions to ______ reactions
unfavorable
hydrolysis of ATP is very favorable under standard conditions why?
- better charge seperation
- better solvation of products (ADP ionizes right away)
- more favorable resonance stabilization of products
hydrolysis of ATP is already thermodynamically favorable because delta G’° is ______
negative
cellular ATP conc. is usually far _____ the equilibrium conc.
above
what is the most sensitive indicator of energy in the cell
AMP
ATP is not the only phosphorylated compound whose hydrolysis is favorable; what is the other one?
PEP to pyruvate by hydrolysis (has same three properties)
you can also hydrolyze molecules other than phosphates for energy such as
hydrolysis of thioesters such as acetyl-CoA
There are molecules with higher delta G than ATP but ATP is good because delta g is not so high that it cannot be
overcome
when you tag something with a phosphate you use it as a good __ group
leaving
when a reaction uses the energy of ATP to proceed forward, ATP is not usually hydrolyzed what occurs is __ ____
group transfer
depending on the reaction you can use PPi, ADP or AMP to move the reaction ____; ATP is very versatile
forward
something with high affinity for electrons in reaction with something with low affinity for electrons provides an ___
emf
the electromotive force (emf) can be harnassed to do
work
what 4 different ways can electrons be transfeered
- directly as electrons
- as hydrogen arons
- as hydride ions
- when something combines directly with oxygen
oxidation reactions always occur togetehr with
reduction reactions
standard reduction potential is __ and measures affinity of electron acceptor for electron
E°
If there is a high affinity for electrons E° is < or > 0
> 0 (greater then)
the one w
when you combine tow redox couples the one with the bigger E° will be flipped or proceed as written
proceed as written
(will absolutely be on exam)
change in E° =
E° red - E° ox
change in E° > 0 means reaction is
favorable
change in G’° = -nF * change in E’°
-n = numbers of electrons and F is fer constant
what is the name of the molecule which donates its electrons
reducing agent
what is standard free energy of ATP?
- small and positive
- large and positive
- large and negative
small and positive
large and negative
the relationship between keq’° and chnage in G’°
-RTln(Keq)
