The Basics of Energy Metabolism

Question 1

The metabolism of all living cells is an (open or closed) system?

Answer 1

open

Question 2

What is the universal molecular carrier for biological energy?

Answer 2

ATP/ADP

Question 3

Is the cell at equilibrium?

Answer 3

No, it is at a steady state and is specifically held out of equilibrium

Question 4

What is Keq

Answer 4

the equilibrium constant of a reaction

Question 5

What is ∆G0’?

Answer 5

The change in Gibbs free energy for a reaction under STANDARD conditions

Question 6

What are the standard conditions?

Answer 6

naught = 1M initial products and reactants
prime = pH7

Question 7

What’s the formula for ∆G0’?

Answer 7

∆G0’ = -R x T x ln(Keq)

Question 8

What are the R and T in the ∆G0’ equation?

Answer 8

R = 8.32
T = 25C (298K)

RT = 2.48 kJ/mol

Question 9

What’s the formula for Keq?

Answer 9

[products] / [reactants]

Question 10

Keq > 1

Answer 10

products favored and exergonic (releases energy)

Question 11

Keq < 1

Answer 11

reactants favored and endergonic (requires energy)

Question 12

∆G0’ > 0

Answer 12

reactants favored and endergonic (requires energy)

Question 13

∆G0’ < 0

Answer 13

products favored and exergonic (releases energy)

Question 14

The Keq of ATP/ADP is what and means what?

Answer 14

Keq = 2.7 x 10^-6
At equilibrium there’s more ADP than ATP

Question 15

What is the ∆G0’ of ATP/ADP and what does it mean?

Answer 15

∆G0’ = 31.8 kJ/mol

ADP (reactant) is favored and the reaction is endergonic (requires energy)

Question 16

What is ∆G’?

Answer 16

The change in Gibbs free energy for a reaction under NON STANDARD conditions

Question 17

What is the equation for ∆G’?

Answer 17

∆G’ = ∆G0’ + (R x T x ln ([products] / [reactants])

Question 18

∆G’ > 0

Answer 18

reactants favored and endergonic (requires energy)

Question 19

∆G’ < 0

Answer 19

products favored and exergonic (releases energy)

Question 20

How do you find the actual [ATP] and [ADP]?

Answer 20

metabolics

Question 21

What’s [ATP] for E. coli?

Answer 21

9.6 x 10^-3 M

Question 22

What’s [ADP] for E. coli?

Answer 22

0.56 x 10^-3 M

Question 23

What’s [PO4^3-] for E. coli?

Answer 23

1 x 10^-3 M

Question 24

What’s the ∆G’ of E. coli for ATP synthesis and what does it mean?

Answer 24

56 kJ/mol
ADP (reactant) is favored and endergonic (requires energy, specifically 56kJ/mol to make ATP)

Question 25

Which do you expect to be larger during ATP synthesis: ∆G0' or ∆G'?

Answer 25

∆G' because ∆G' = ∆G0' + (RT x ln ([products] / [reactants])) and the [products] / [reactants] is > 1

Question 26

The electron acceptor is the (oxidant or reductant)?

Answer 26

oxidant

Question 27

The electron donor is the (oxidant or reductant)?

Answer 27

reductant

Question 28

Reduction (gains or loses) electrons?

Answer 28

Reduction Is Gain (RIG)

Question 29

Oxidation (gains or loses) electrons?

Answer 29

Oxidation Is Loss (OIL)

Question 30

NADPH is an electron (donor or acceptor)?

Answer 30

electron donor

Question 31

NADP+ is an electron (donor or acceptor)?

Answer 31

electron acceptor

Question 32

NADH is an electron (donor or acceptor)?

Answer 32

electron donor

Question 33

NAD+ is an electron (donor or acceptor)?

Answer 33

electron acceptor

Question 34

Reduction potential

Answer 34

measurement of how easily a molecule can take up electrons

Question 35

oxidation potential

Answer 35

measurement of how easily a molecule can give up electrons

Question 36

A hydride = what?

Answer 36

1 H- = 1 (H+) + 2 e-

Question 37

[H] = what?

Answer 37

1 (H+) + 1 e-

Question 38

What is the equation for ∆G0’ ?

Answer 38

∆G0’ = -n x F x ∆E0' n = number of e- F = 97 kJ / V ∆E0' = standard reduction potential

Question 39

What is ∆E0'?

Answer 39

the STANDARD reduction potential (E0' of e- acceptor) - (E0' of e- donor)

Question 40

∆E0' < 0

Answer 40

more likely to give up e- (mainly oxidized)

Question 41

∆E0' > 0

Answer 41

more likely to keep e- (mainly reduced)

Question 42

What does NAD stand for?

Answer 42

Nicotinamide Adenine Dinucleotide

Question 43

What does NAD do?

Answer 43

hydride transfer (H- = 2 e- + H+)

Question 44

What is the structure of NAD+ and NADP+?

Answer 44

Question 45

What is the structure of NADH and NADPH?

Answer 45

Question 46

What's the structure equation for NAD(P)+ to NAD(P)H?

Answer 46

Question 47

What's the oxidation half reaction of NAD(P)+/NAD(P)H?

Answer 47

NAD(P)H -> NAD(P)+ + (H-)

Question 48

What's the reduction half reaction of NAD(P)+/NAD(P)H?

Answer 48

NAD(P)+ + (H-) -> NAD(P)H

Question 49

What's the E0' of NAD(P)+ / NAD(P)H and what does it mean?

Answer 49

-0.32 V NAD(P)H wants to give up e-

Question 50

What is ∆G0' of NAD(P)+ / NAD(P)H and what does it mean?

Answer 50

∆G0' = 0 because both NAD(P)+ (e- acceptor) and NAD(P)H (e- donor) have a E0' = -0.32 so ∆E0' = 0 which makes the entire formula = 0 neither the product or reactant are favored

Question 51

What's non-standard conditions?

Answer 51

pH 7 and 25 C (298 K) but [actual]

Question 52

What's ∆E'?

Answer 52

the reduction potential under NON-STANDARD conditions (actual conditions)

Question 53

What's the E' of NADP+ / NADPH and what does it mean?

Answer 53

E' = -0.373 V NADPH wants to give up e-

Question 54

What's the ratio of NADH / NAD+?

Answer 54

1/31 (ln this)

Question 55

What's the ratio of NADP+ / NADPH?

Answer 55

57/1 (ln this)

Question 56

What's the E' of NAD+ / NADH and what does it mean?

Answer 56

E' = -0.275 V NADH wants to give up e-

Question 57

What is the formula for E'?

Answer 57

E' = E0' - ( (RT/nF) x ln( [red] / [ox]) )

Question 58

The transfer of a hydride from NADPH to NAD+ is (exergonic or endergonic)?

Answer 58

exergonic

Question 59

What's the ∆G' of NADPH to NAD+ and what does it mean?

Answer 59

∆G' = -19 kJ/mol NAD+ is favored and is exergonic (releases energy)