Biology: Biochemistry TPR Review Thermodynamics

Question 1

Kinetic energy

Answer 1

active energy/movement of molecules

Question 2

Potential energy

Answer 2

energy stored in chemical bonds

Question 3

1st law thermo/law conservation of energy

Answer 3

energy of universe is constant - energy is conserved cannot be created or destroyed

Question 4

2nd law thermo

Answer 4

the (entropy) of the universe tends to increase = spontaneous rxns tend to increase the disorder of the universe

Question 5

S

Answer 5

entropy ( not to be confused with enthalpy) - disorder

Question 6

H

Answer 6

enthalpy (not to be confused with entropy) - sum of internal energy and product of pressure x volume

Question 7

Reactions that occur without net addition of energy are:

Answer 7

exergonic: spontaneous (exer = energy exits the body)

Question 8

Reactions that only occur if energy is added

Answer 8

endergonic: nonspontaneous

Question 9

Reactions with a negative deltaH (enthalpy) are called: what do they do?

Answer 9

exothermic; give off heat

Question 10

Reactions with a positive deltaH (enthalpy) and called: what do they do?

Answer 10

endothermic; require input of heat

Question 11

The value of deltaG depends on:

Answer 11

[reactants] and [products] which vary in the body

Question 12

keq primary

Answer 12

ratio of products to reactants at equilibrium

Question 13

What calculating DeltaG of the body, what do you need unlike the other equation?

Answer 13

Q, the actual [A,B,C,D] etc.

Question 14

Define Equilibrium

Answer 14

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

Question 15

When deltaG = 0

Answer 15

equilibrium - forward rxn rate = backward rxn rate, net [reactants] [products] do not change

Question 16

The transition state of all reactions are:

Answer 16

unstable and require a lot of energy to produce

Question 17

Energy required to produce the transition state is:

Answer 17

Ea - activation energy

Question 18

The ____ determines the kinetics of a reaction

Answer 18

Ea barrier

Question 19

Catalyst (like biological enzymes)

Answer 19

lowers Ea. by stabilizing the transition state making it more thermodynamically favorable w/out changing the deltaG - regenerated with each reaction cycle

Question 20

Enzymes (biological catalysts) affect the free energy between reactants and products

Answer 20

NO - only have kinetic role not thermodynamic one

Question 21

Photosynthesis

Answer 21

process by which plants store energy from the sun in the bond energy of carbs

Question 22

photoautotrophs

Answer 22

plants - use energy from light to make “auto” / food

Question 23

chemoheterotrophs

Answer 23

energy from chemicals “chemo” produced by other “hetero” living things

Question 24

Oxidation - loss of electrons : list code words on MCAT

Answer 24

1) . gain of oxygen atoms
2) . loss of hydrogen atoms
3) . loss of electrons

Question 25

Reduction - Gain of electrons: list of code words on MCAT

Answer 25

1) . Loss of oxygen atoms
2) . Gain of hydrogen atoms
3) . Gain of electrons

Question 26

Catabolism

Answer 26

The process of breaking down molecules

Question 27

Anabolism

Answer 27

Building up metabolism

Question 28

Define Q

Answer 28

the ratio of products to reactants in any setup

Question 29

Define Keq

Answer 29

The ratio of products to reactants AT EQUILIBIUM

Question 30

A disturbance in the balance of reactants and products (addition or removal of a reactant/product) will cause a change in _______ but not ____________ . Why?

Answer 30

Q, but not Keq. Because Q is the ratio of p/r, and Keq is p/r ratio AT EQUILIBRIUM. At equilibrium the concentrations stay the same so this makes sense.