bioenergetics 1 and 2?

Question 1

anabolic reactions

Answer 1

• synthesis of complex molecules from simple ones
• energy-storing reactions

Question 2

catabolic reactions

Answer 2

• degradation of complex molecules into simpler ones
• energy is released

Question 3

metabolism

Answer 3

total chemical reactions

Question 4

1st law of thermodynamics

Answer 4

energy is neither created nor destroyed - only transformed

Question 5

what are the different types of energy?

Answer 5

• kinetic
• potential (gravitational and elastic)
• thermal (heat)
• chemical
• electrical
• light
• nuclear
• mechanical

Question 6

why does energy eventually lose the ability to do useful work?

Answer 6

due to degradation of energy:
as energy undergoes multiple transformations, it becomes increasingly dispersed and less concentrated in forms that can be harnessed to do useful work

Answer 7

• “quality” changes
• The energy is ‘diluted’
• Energy can lose its ability to ‘do’ work

Question 8

what is Gibbs free energy?

Answer 8

energy that can be harvested by an organism

Question 9

Gibbs free energy equation?

Answer 9

enthalpy = free energy + (absolute temperature x entropy)

or

H = G + (TxS)

Question 10

heterolytic fission

Answer 10

pair of electrons is taken by one of the atom

Question 11

homolytic fission

Answer 11

he pair of electrons is split between the separated atoms

Question 12

nucleophile

Answer 12

electron rich
- negatively charged or have unshared electron pair
- easily form covalent bonds with electron deficient centers

Question 13

electrophile

Answer 13

electron-deficient
- positively charged, contain an unfilled valence electron shell or contain a electronegative atom - form covalent bonds with electron rich centers

Question 14

electrophile examples

Answer 14

protons
metal ions
carbonyl carbon atoms
cationic immune

Question 15

nucleophile examples

Answer 15

hydroxyl groups
sulfhydryl group
amino group
imidazole group

Question 16

group transfer reactions

Answer 16

nvolve the transfer of an electrophilic group from one nucleophile to another –> nucleophilic substitution

Question 17

oxidation reaction

Question 18

reduction reaction

Question 19

redox reaction

Question 20

isomerisation

Answer 20

involve the intra molecular shift of a hydrogen to change the location of a double bond

Question 21

rearrangement

Answer 21

produce altered carbon skeletons

Question 22

Gibbs free energy equation

Answer 22

ΔG = ΔH - ( T x ΔS)

Gibbs free energy = change in enthalpy - ( temperature x change in entropy)

Question 23

decarboxylation

Answer 23

Reaction are often followed by electron/bond rearrangement to find the most stable form

Question 24

what does ΔG < 0 indicate?

Answer 24

• value is negative
• process is spontaneous
• dec in Gibbs energy accompanied by inc in entropy which doves reaction forwards

Question 25

what does ΔG = 0 indicate?

Answer 25

• the system is at equilibrium
• occurs at a constant rate in both directions

Question 26

what does ΔG > indicate?

Answer 26

• value is positive
• the process is not spontaneous

Question 27

in a spontaneous process, a system:

Answer 27

• gives up energy ( so dec in H)
  and/or
• becomes more random (inc in S)

Question 28

1st law of thermodynamics

Answer 28

energy is neither created nor destroyed, only transformed

Question 29

2nd law of thermodynamics

Answer 29

all energy transformations ultimately increase the entropy of the universe

Question 30

how may a non-spontaneous reaction occur?

Answer 30

• if lined reaction is sufficiently exergonic ( releases a lot of free energy)
• i.e if ΔG1 + ΔG2 < 0

Question 31

draw energy diagram for endergonic reactions

Question 32

draw energy diagram for exergonic reactions

Question 33

How would the addition of a catalyst to the reaction S⇋P affect the difference between the free energies of S and P in their ground states (∆G’°)?

Answer 33

∆G’° would not change

Question 34

For the enzyme-catalyzed reaction E + S ⇋ ES ⇋ E + P, what equation defines the rate at which ES is formed?

Answer 34

k1([E_t] - [ES])[S]

Question 35

How can the Michaelis-Menten constant, be derived from this Lineweaver-Burk plot?

Answer 35

The x-intercept is equal to -1/Km therefore Km= -1/(x-intercept)
the equation of a line is y = mx + b.

Michaelis-Menten equation states that
V0= (V_{max}[S])/(K_m + [S]

the inverse of this equals
(

.This equation is the simple y=mx + b equation that defines the line in the Lineweaver-Burk plot.
Hint #55 / 6
Because x = 1/[S], we can see that the slope of this line would be equal to

. Also notice that

is the inverse of the y-intercept.

Question 36

If the enzyme-catalyzed reaction E + S ⇋ ES ⇋ E + P is proceeding at or near the V

of E, what can be deduced about the relative concentrations of S and ES?

Answer 36

S is abundant, and [ES] is at its highest point.

Question 37

What relative values of Km and kcat would describe an enzyme with a high catalytic efficiency?
Choose 1 answer:

Answer 37

low Km and high Kcat

Question 38

For the enzyme-catalyzed reaction E + S ⇋ ES ⇋ E + P, what is the value of K

if [S]=25, and the initial reaction velocity is half of V?

Answer 38

25

Question 39

With respect to the binding of regulatory compounds, what properties define an enzyme as being allosteric?

Answer 39

reversible
non-covalent binding of regulatory compounds