I'd like to get to the bottom of lecture 4 Flashcards
In what direction do spontaneous processes occur?
“Spontaneous processes occur in directions that increase the overall disorder of the universe.”
Maximum disorder is most probable.
“active” conformations of a protein
The “active” conformations of proteins are typically highly ordered, discrete structures of relatively LOW entropy compared to the “unfolded” states of the proteins.
exergonic
Processes with a negative free energy changes (-deltaG)
endergonic
Processes with a positive free energy changes (+deltaG)
thermodynamically favored process
tends in the direction that minimizes free energy (results in a negative deltaG); this is one way of
stating the second law of thermodynamics
is Gibbs Free Energy related to chemical equilibrium?
yes, Gibbs Free Energy is dependent on the concentrations of the reactants and products of a reactions and thus, is related to “chemical equilibrium”.
what does delta H depend on?
the numbers and kinds (covalent & non-covalent) of BONDS made and broken upon going from initial to final state.
delta S depends on?
the mobilities and/or randomness of the system and surroundings upon going from initial to final state
The more isoenergetic states for a system, the _______ the entropy of that system.
greater
The equation deltaG = RT ln ([A]2/[A]1) predicts:
- ) If [A]2 < [A]1, deltaG is negative; thus, transfer from region 1 to region 2 is favorable.
- ) Conversely, for a system where [A]2 > [A]1, deltaG is positive; thus, transfer from region 1 to region 2 would not be favorable.
- ) If is [A]2 = [A]1, deltaG is zero; thus, there is no net driving force in either direction for the transfer of A. The system is at equilibrium.
From the analysis of deltaG = RT ln ([A]2/[A]1) , we can conclude that if a substance is able to pass through a membrane…
the direction of favorable transfer will always be from the region of higher concentration to the region of lower concentration
Le Chatelier’s Principle
Any deviation from equilibrium stimulates a process that tends to restore the system to equilibrium. All isolated systems must therefore inevitably reach equilibrium”
How do we get a thermodynamically unfavorable reaction to occur?
- ) Coupling to a highly favorable reaction.
2. ) Maintaining a “steady-state” [products] far below the equilibrium [products]
Driving an unfavorable process by coupling it to a favorable one requires the availability in ____ of _______ that can undergo reactions with _____________.
cells
compounds
large negative free energy changes.
High-energy phosphate compounds have very large __________ free energies of hydrolysis.
negative
most important high energy compounds?
phosphates, which can undergo hydrolytic release of their phosphate groups in aqueous solution.
energy transducers in the cell
helps drive an unfavorable process by coupling it to a favorable one.
This requires the availability in cells of compounds that can undergo reactions with large negative free energy changes.
The orthophosphate ion
HPO_4^-2
often abbreviated as Pi (inorganic phosphate), is capable of a wide variety of resonance forms
Resonance stabilization applies in all of the phosphate hydrolysis reactions shown previously.
release of the orthophosphate results in __________
entropy increase in the system and is therefore favored
How can a thermodynamically unfavorable (endergonic) reaction can be made favorable?
by coupling it to a highly favorable (exergonic) reaction
what does the oxidation of nutrients provide?
The oxidation of nutrients such as carbohydrates or fats provides cells with substantial free energy for the synthesis of ATP.
How is energy stored once its released when transferring electrons from nutrients?
its stored in the form of a proton gradient across the membrane.
whats the driving force for the synthesis of ATP in mitochondria
the proton gradient
how does the electron transfer take place?
The electron transfer occurs via a series of linked oxidations and reductions, or “redox” reactions
To understand the processes by which metabolic energy is extracted from nutrients, one must understand
how to calculate the free energy available from a redox reaction.
A complete redox reaction must show:
one reactant as an electron acceptor, which becomes reduced by gaining electrons,
And another reactant as an electron donor, which becomes oxidized by losing electrons.
reductant (or reducing agent)
The electron donor is the reductant (or reducing agent), which becomes oxidized.
oxidant (or oxidizing agent),
The electron acceptor is the oxidant (or oxidizing agent), which gets reduced.
diffusion is an ________ driven process
entropy
whats the indicator of spontaneity?
my nigga gibbs (Free energy)
what drives protein folding?
J gibbs (deltaG)
are living cells at equilibrium?
na brah
Concentrations of reactants and products are typically far from the equilibrium values (Q doesnt equal Keq).
If Q > Keq
then deltaG > 0 (reverse reaction is favorable)
If Q = Keq
then deltaG = 0 (at equilibrium)
If Q < Keq
then deltaG < 0 (reaction favorable as written)
is Homeostasis the same thing as equilibrium?
naw bitch!
Homeostasis must not be confused with equilibrium!
homeostasis or the homeostatic condition.
life occurs within relatively narrow ranges of temperature, pH, and concentrations for ions and metabolites, this set of conditions is referred to as homeostasis
