review of thermodynamics for biochemistry

Question 1

what is a system

Answer 1

any part of the universe chosen for study
example: cell

Question 2

closed system

Answer 2

allows only exchange of energy with surrounds and not matter

Question 3

what is an open system

Answer 3

able to exchange energy and matter with surroundings

Question 4

what is internal energy (E or U)

Answer 4

all forms of energy that can be exchanged via physical and chemical reactions

Question 5

what are some examples of internal energy

Answer 5

1. kinetic energy of systems atoms and molecules
2. vibrational and rotational energy
3. all energy stored in chemical bonds

Question 6

what can change a systems internal energy

Answer 6

exchange of heat or work with the surroundings

Question 7

what is the first law of thermodynamics

Answer 7

energy is conserved, it cannot be created or destroyed

Question 8

what is the equation for a cell for internal energy

Answer 8

Delta U = q-w
q = heat absorbed by the system
w= Work done by the system on the surroundings

Question 9

what is delta H

Answer 9

change in enthalpy
Delta H = Delta U bc most biochemical reactins occur in solution and not gas

Question 10

what is a state function and what are the state funcitons

Answer 10

a state function is independent of path their values depends on only the initial and final state of the system
- delta U
-delta H

Question 11

what is not considered a state function

Answer 11

q and w because they can be exchanged with the surroundings

Question 12

what is entropy

Answer 12

the measure of disorder in a system
- entropy is always increasing

Question 13

what is the equation for the universe

Answer 13

change in the system + change in surroundings = change in universe >=0

Question 14

what is the equation for entropy

Answer 14

S = KbLnW
- Kb= boltzmann’s constant, 1.3907 x10^-23j/k
W= total ways a system can combine

Question 15

what is the equation for entropy at constant pressure

Answer 15

delta S>= q/change in temperature
q = heat absorbed in a reversible process in which the system goes from one state to anoter

Question 16

as heat increases what happens to entropy

Answer 16

the entropy also increases

Question 17

what is gibbs free energy

Answer 17

change for a process at a constant temperature and pressure and it is what we now use as a isolated system

Question 18

what is equation for gibbs free energy

Answer 18

delta G= deltaH-T(delta S)

Question 19

when g is less than 0 what reaction is that called

Answer 19

exergonic reaction
energy is being released
spontaneous
thermodynamically favorable

Question 20

when g is greater than 0 what reaction is that called

Answer 20

endergonic (energy consumption)
energy is being consumed
thermodynamically unfavorable reaction

Question 21

what does it mean when g =0

Answer 21

the reaction is at equilibrium

Question 22

life involves a temporary decrease in what

Answer 22

entropy, paid for by the expenditure of energy

Question 23

where does delta H come from

Answer 23

numerous weak interactions; H-bonds + other non covalent interactions within the proteins and with the solvent

Question 24

what does G depend on

Answer 24

concentration

Question 25

what is the equation for delta G

Answer 25

delta G + RTLnQ
G = change in heat - temp (change in entropy 2)

Question 26

when G is + what does that mean

Answer 26

engergonic reaction
not thermodynamically favorable

Question 27

in the equtation G = H -T (s)
what must be true for each of the values for G to be negative

Answer 27

-G= (H must be negative)(-TS has to be positive)

Question 28

where does the negative H come from in the delta G equation

Answer 28

numerous weak interactions; h onds + other non covalent interactions within the protein

Question 29

are living things ever at equilibrium

Answer 29

never bc that means death

Question 30

what happens at 10^-15 s(femto)

Answer 30

excitation of chlorophyll

Question 31

what happens at pico (10^-12

Answer 31

charge separation in photosynthesis

Question 32

what happens at nano 10^9

Answer 32

hinge protein action

Question 33

what happens at 10^8

Answer 33

florecence lifetime