Lecture 5: Bioenergy

Question 1

Energy Charge (EC)

Answer 1

measure of [ATP], [ADP], [AMP] in cell

reflects amount ATP for metabolic reactions

Question 2

first law of thermodynamics

Answer 2

nrg not created or destroyed

nrg conversion in bio systems is never 100%, its good, but some is lost as heat

Question 3

Second Law of Thermodynamics

Answer 3

w/o nrg input, all natural process tend toward DISPERSON OF ENERGY (disorder)

Question 4

measure of disorder is…

Answer 4

entropy (S)

Question 5

bomb calorimeter

Answer 5

can determine nrg avliable oxidation of rreduced compound

Question 6

calorie

Answer 6

amount of heat nrg need to raise 1 kg water 1 degree C at 1 atmospheric pressure

Question 7

total nrg potential of 1 gram glucose is…

Answer 7

SAME REGARDLESS OF METABOLIC PATH TAKEN

15.7 kJ of nrg

Question 8

true or false: total amount of nrg availalble does NOT tell you if glucose ox is favorable or unfavorable

Answer 8

TRUE

Question 9

to know if glucose oxidation is favorable or unfavorable…

Answer 9

know the change in GIBBS FREE ENERGY (delta G)

Question 10

When delta S is greater than zero…

Answer 10

randomness is increasing

Question 11

to restrain disorder from increasing…

Answer 11

nrg needs to be provided

Question 12

in order to stay alive…

Answer 12

one must maintain order and prevent reaching equilibrium with the environment.

inc in entropy happens when a cell dies and its contentes equilibrate with environment

Question 13

Ice melting as increase in entropy

Answer 13

at liquid state, the H bonds in the molecules break and reform more than when frozen

Question 14

Delta G greater than zero…

Answer 14

reaction UNFAVORABLE

ENDERGONIC (reabsorbs energy)

Question 15

Delta G less than zero

Answer 15

reaction FAVORABLE

EXERGONIC (releases energy)

Question 16

Delta G = zero

Answer 16

reaction at EQUILIBRIUM

concs not changing (but the concs arent equal)

Question 17

Gibbs free energy

Answer 17

relates enthalpy, temp, and entropy to predict SPONTANETIY of a reaction

Question 18

enthalpy means

Answer 18

bonding

is represented by H

Question 19

Gibbs free energy equation

Answer 19

Delta G= Delta H-TDeltaS

Question 20

values of delta G tell whether favorable…

Answer 20

in DIRECTION WRITTEN

Question 21

DeltaG^0’ Conditions…

Answer 21

1M starting conc of all reactants and products
298K
pH 7
1 atm
55M H2O

DeltaG^0’ is Standard Free Energy Change

Question 22

DeltaG^0’ is determined…

Answer 22

experimentally. ste up with standard conditions. add an enzyme (usually)

Question 23

note about enzymes…

Answer 23

enzymes change rate, NOT concentrations at the end

Question 24

DeltaG^0’ equation

Answer 24

DeltaG^0’=-RKlnKeq

R is gas constant

Question 25

Keq=

Answer 25

[product]eq/[reactant]eq ratio of product and reactant concs when reaction has reached equilibrium

Question 26

DeltaG^0' and Keq

Answer 26

CONSTANTS | if you have one, you can calculate the other

Question 27

Keq can tell you...

Answer 27

its a measure of reaction directionality, so it can tell you if reaction is favored

Question 28

Keq greater than one

Answer 28

product formation favored | exergonic

Question 29

Keq less than one

Answer 29

product formation UNfavored | endergonic

Question 30

What can be used to describe spontaneity of a reaction

Answer 30

Keq and DeltaG^0'

Question 31

endergonic when

Answer 31

Keq0

Question 32

exergonic when

Answer 32

Keqq>1 | DeltaG^0' <0

Question 33

DeltaG^0' <0

Answer 33

reaction favorable in direction written

Question 34

DeltaG^0' >0

Answer 34

reaction is UNfavorable in direction written

Question 35

change in free energy equation that takes into account standark free energy change

Answer 35

deltaG=DeltaG^0' +RTlnQ temp and concs can change now when reaction is at eq, deltaG=0

Question 36

Q

Answer 36

[products]actual/[reactants]actual

Question 37

mass action ratio

Answer 37

Q | measure of actual concs of reactants and producs under actual conditions

Question 38

more negative delta G means...

Answer 38

more favorable

Question 39

Coupled reactions

Answer 39

share metabolic intermediates product of one rxn may be unfavorable, but if coupled with a reaction that is favorable enough to make the total deltaG be negative, the overall reaction IS FAVORABLE (see slide 19 if needed)

Question 40

ATP Hydrolysis

Answer 40

phosphoryl transfer used to drive reactions that are otherwise unfavorable nrg in 2 ATP phosphoanhydride bonds to stim catalysis and metabolix flux

Question 41

ATP Hydrolysis ex: convert glutamate to glutamine

Answer 41

``` use glutamine synthase glutamate->glutamine= +14 ATP->ADP+Pi= -30 overall NEGATIVE (favorable) SEE SLIDE 22 ```

Question 42

so what exactly is ATP doing in ATP hydrolysis?

Answer 42

phosphoryl group is transferred on to an unstable compound nrg is avliable from unstable compound's hydrolysis, THATS what drives the process KNOW that we are forming a phosphorylated intermediate and THATS what drives the reaction

Question 43

Adenylate System Energy Charge of the Cell

Answer 43

``` tells how much nrg available in cell at given time #phosphate bonds available for reaction ``` usually between 0.7 and 0.9 because of regulation of flux through anabolic and catabolic pathways

Question 44

Energy Charge Equation

Answer 44

([ATP] + .5[ADP])/[ATP]+[ADP]+[AMP]