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Flashcards in craven Deck (45):
1

how do you represent a unimolecular irreversible reaction

A ----> B
k

2

how do you represent how long a molecule stays in state A

1/k

3

if k = 0.02 min-1 in a unimolecular irreversible reaction, how long does molecule stay in state A

1/0.02 = 50 minutes

4

what does a single molecule timecourse show

how long a molecule stays in each state

5

what is the rate of change of A in the reaction A--->B

-k[A]
or -k nA

6

If k=5s-1 and there are 500 molecules in a system in state A at t=0, how many molecules
(approximately) will convert from A to B in the first 10 ms

-k x nA
-5 x 500
= 2500
number of changing state = r.o.c x time
10ms = 0.01s
2500 x 0.01
=25

7

if k = 20s-1 what is the rate of change of [A] if [A] = 100nM

= -20 x 100nMs-1
= -2000nMs-1
= -2μMs-1

8

why will the numerical solution always be slightly approximate for unimolecular irreversible reactions?

assume that the rate of change of [A] is constant during the whole timestep

9

what is the analytical solution

[A] = [A]o exp(-kt)

10

what does [A]o stand for

conc of A at start of reaction

11

what are the advantages of using the analytical solution

exact
works for any [A]o, k & t

12

what is the disadvantage of analytical solution

can only be used for simple cases

13

what are the advantages of numerical solution

can apply to complex cell biology models - systems biology

14

how do you work out the half time for a unimolecular irreversible reaction

set [A] = [A]o/2 and plug into equation
[A] = [A]o exp(-kt)

15

how do you represent a bimolecular irreversible reaction

A + B ----> C
k

16

what order is a bimolecular irreversible reaction

second

17

what is the rate of change of [C] in a bimolecular irreversible reaction

-k [A][B]

18

what are the units of k in a bimolecular irreversible reaction (second order)

mM-1s-1

19

how do you work out the average time in A in a bimolecular irreversible reaction

1/k[B]

20

what can't a reaction go faster than

diffusion controlled limit

21

what is the largest value that a second order rate constant can be

about 10^9M-1s-1

22

why is k generally smaller than what is calculated in bimolecular irreversible reactions

most collisions are unsuccessful

23

why is calculating the timecourse for a bimolecular irreversible reaction more complex than a unimolecular irreversible reaction

the liklihood of A reacting with B changes as B is used up

24

what is the rate of change of A in a bimolecular irreversible reaction

= k'[A]

25

what does k' stand for in the r.o.c of A equation for bimolecular irreversible reactions

k' = k[B]

26

all molecular reactions are in principle....

reversible

27

how do you represent a unimolecular reversible reaction

k1
A-------->B

28

what do you need to remember when drawing the single molecular timecourse for bimolecular reversible reaction

stochastic (random) nature of process

29

how do you represent time spent in B/time spent in A

k1/k-1

30

what does k1/k-1 also represent in unimolecular reversible reactions

K = equilibrium constant

31

give some examples of bimolecular reversible reactions

drug based molecules
receptors
transcription factors
enzyme and substrate

32

how do you represent a bimolecular reversible reaction

k1
A + B ------> AB

33

where will a bimolecular reversible reaction settle down to equilibrium

when the rates of A+B forming a complex and AB dissociating are equal

34

is A + B -----> first order or second order

second order

35

is AB -----> A + B first order or second order

first order

36

how do you represent rate of formation of AB in a bimolecular reversible reaction

k1[A][B]

37

how do you represent the rate of loss of AB in a bimolecular reversible reaction

k-1[AB]

38

what does k-1/k1 define in bimolecular reversible reaction at equilibrium

KD - dissociation constant

39

what does k1/k-1 define in bimolecular reversible reaction at equilibrium

KA - association constant

40

how can k1 also be defined in bimolecular reversible reactions

kon

41

how can k-1 also be defined in bimolecular reversible reaction

koff

42

...... k1 favours binding

bigger

43

..... k-1 favours binding

smaller

44

KD is ..... for higher affinity binding

smaller

45

in a bimolecular reversible reaction what does [AB]/[A] equal

[B]/KD