Biology: Biochemistry TPR Review Thermodynamics Flashcards
Kinetic energy
active energy/movement of molecules
Potential energy
energy stored in chemical bonds
1st law thermo/law conservation of energy
energy of universe is constant - energy is conserved cannot be created or destroyed
2nd law thermo
the (entropy) of the universe tends to increase = spontaneous rxns tend to increase the disorder of the universe
S
entropy ( not to be confused with enthalpy) - disorder
H
enthalpy (not to be confused with entropy) - sum of internal energy and product of pressure x volume
Reactions that occur without net addition of energy are:
exergonic: spontaneous (exer = energy exits the body)
Reactions that only occur if energy is added
endergonic: nonspontaneous
Reactions with a negative deltaH (enthalpy) are called: what do they do?
exothermic; give off heat
Reactions with a positive deltaH (enthalpy) and called: what do they do?
endothermic; require input of heat
The value of deltaG depends on:
[reactants] and [products] which vary in the body
keq primary
ratio of products to reactants at equilibrium
What calculating DeltaG of the body, what do you need unlike the other equation?
Q, the actual [A,B,C,D] etc.
Define Equilibrium
The point at whee the rate of rxn in the forward direction equals the rate of reaction in the reverse direction - over concentrations remain the same
When deltaG = 0
equilibrium - forward rxn rate = backward rxn rate, net [reactants] [products] do not change
The transition state of all reactions are:
unstable and require a lot of energy to produce
Energy required to produce the transition state is:
Ea - activation energy
The ____ determines the kinetics of a reaction
Ea barrier
Catalyst (like biological enzymes)
lowers Ea. by stabilizing the transition state making it more thermodynamically favorable w/out changing the deltaG - regenerated with each reaction cycle
Enzymes (biological catalysts) affect the free energy between reactants and products
NO - only have kinetic role not thermodynamic one
Photosynthesis
process by which plants store energy from the sun in the bond energy of carbs
photoautotrophs
plants - use energy from light to make “auto” / food
chemoheterotrophs
energy from chemicals “chemo” produced by other “hetero” living things
Oxidation - loss of electrons : list code words on MCAT
1) . gain of oxygen atoms
2) . loss of hydrogen atoms
3) . loss of electrons
