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