Unit 1 Bioenergetics

Question 1

entropy

Answer 1

(S)

randomness associated with a given system

Question 2

enthalpy

Answer 2

(H)

measure of heat content (thermodynamic potential) of a system

Question 3

free energy

Answer 3

the amount of thermodynamic energy in a system that can be converted into work at a given temp and pressure

Question 4

high energy compounds

Answer 4

compounds with bonds that release greater than 7 kcal/mol of energy when broken
(∆G= -7; chemical energy of greater than 7 kcal/mol)

Question 5

Oxidation-reduction reaction:

Answer 5

a chemical reaction involving the transfer of electrons away from one or more compounds (the oxidized compounds) to one or more other compounds (the reduced compounds)

Question 6

1st law of thermodynamics

Answer 6

energy is neither created nor destroyed. Energy can be converted into different forms but is always conserved

Question 7

2nd law of thermodynamics

Answer 7

entropy of the universe is constantly increasing

Question 8

kinetic energy

Answer 8

• radiant energy
• thermal
• mechanical
• electric

Question 9

radiant energy

Answer 9

• kinetic energy

- carried in photons from sun, the ultimate source of all forms of energy in living systems

Question 10

thermal energy

Answer 10

• kinetic energy

- protein molecules function optimally at a particular temperature or need certain thermal energy to function

Question 11

mechanical energy

Answer 11

• kinetic energy

- movement of cells and cell components

Question 12

electrical energy movement

Answer 12

• kinetic energy

- movement of charged particles down gradients of electric potential

Question 13

potential energy

Answer 13

1. stored in chemical bonds
2. stored in concentration gradients
3. stored in electric fields from charge separation
4. stored in redox pairs

Question 14

-∆G

Answer 14

• reaction is thermodynamically favorable

- will occur spontaneously at any temp

Question 15

∆G is

Answer 15

Gibbs free energy constant

Question 16

+∆G

Answer 16

• rxn not favorable

- will not occur spontaneously at any temp

Question 17

Gibbs free energy equations

Answer 17

∆G = ∆G0 + (RT * ln [PRODUCTS]/[REACTANTS])

b) ∆G0 = -RT * ln (Keq)
c) ∆G = ∆H – (T * ∆S )

Question 18

∆H is

Answer 18

change of enthalpy (of bond energy) of a reaction

Question 19

exothermic rxn

Answer 19

-heat released

∆H is negative (favorable)

Question 20

endothermic rxn

Answer 20

-heat is absorbed

∆H is positive (unfavorable)

Question 21

∆G < 0

Answer 21

spontaneous

Question 22

∆G > 0

Answer 22

nonspontaneous

Question 23

∆G = 0

Answer 23

equilibrium

Question 24

∆S is

Answer 24

Sprod -Sreact

change of entropy or randomness of a rxn

Question 25

-∆S

Answer 25

unfavorable

Question 26

+∆S

Answer 26

favorable

Question 27

∆G ° ' determines the

Answer 27

position of equilibrium in a chemical rxn

Question 28

a thermodynamically favorable run may not occur because

Answer 28

the rxn rate is limited by high activation energy

Question 29

how to calculate ∆E

Answer 29

subtract Eo of the electron donor from the Eo of the electron acceptor

Question 30

Eo of a molecule is high when_______ | and high negative when ____

Answer 30

the molecule is more electronegative the molecule is more electropositive

Question 31

when ∆E is positive,

Answer 31

∆G is negative and the rxn is more spontaneous

Question 32

Coupling means

Answer 32

the sum of the run determines the spontaneity, thus allowing a rxn of +∆G to continue if paired with a -∆G rxn of greater absolute value can couple a very favorable rxn with an unfavorable one to make the overall rxn favorable

Question 33

High energy bonds

Answer 33

1. thioester bonds C--S: acetyl CoA 2. Hi energy phosphate bonds

Question 34

hi energy phosphate bonds

Answer 34

1. Phosphoanhydride (P--O--P bonds, ATP) 2. (P--N) bonds: phosphocreatine 3. (C--O--P) bonds: phosphoenolpyruvate

Question 35

the source of energy in all cells

Answer 35

thioester bond in acetyl CoA

Question 36

nucleophilic attack can occur at ______ on ATP

Answer 36

3 locations of ATP | but beta and delta release much more energy than the alpha

Question 37

the energy yield from ATP, ∆G, depends on

Answer 37

concentrations of reactants and products in the cell

Question 38

oxidation

Answer 38

loss of electrons

Question 39

reductions

Answer 39

gain of electrons

Question 40

reduction potential E is a measurement of

Answer 40

readiness with which an atom or molecule accepts an electron relative to H+

Question 41

the more positive the E, the

Answer 41

more a molecule like electrons

Question 42

the more negative the E value, the

Answer 42

more it likes to donate electrons

Question 43

reduction potential is measure in

Answer 43

volts

Question 44

the energy yield from oxidation of fuels depends on ______

Answer 44

the oxidation states of carbon in different compounds

Question 45

in cells, _____ is the major source of electrons, _______ is the final electron acceptor

Answer 45

glucose O2

Question 46

the "circuit" for electron flow is a

Answer 46

series of proteins, including cytcochromes with co-factors such and Fe2+/Fe3+ containing heme groups that are alternatively oxidized/reduced and release energy in small steps

Question 47

emf is used to

Answer 47

make high energy compounds ATP, NADPH, NADPH that are used to do biological work

Question 48

potential energy is stored as

Answer 48

NADH

Question 49

ATP is made by

Answer 49

harnessing the energy in gradients of H+ concentration and electrical potential across the inner membrane of mitochondria

Question 50

high energy phosphate bonds

Answer 50

1. ATP 2. P-N Bonds (phosphocreatine) 3. C-O-P bonds: (phosphoenolpyruvate)

Question 51

in cells, major source of electrons

Answer 51

glucose

Question 52

in cells, final electron acceptor

Answer 52

O2

Question 53

compounds such as _____ give off lots of energy when they combust, they have large ____

Answer 53

carbohydrates lipids ΔG

Question 54

one of the major ways to harness energy for production of ATP

Answer 54

oxidation of glucose | ΔG'o= -686 kcal/mol