Translational Level

Question 1

Euk. mRNA has longer half-life than that in proka.

Define half-life

Answer 1

Time taken for half the initial amount of RNA to be degraded

Question 2

2 ways of how half-life of mRNA can be regulated by

Answer 2

1. mRNA degradation

2. Destabilising elements

Question 3

4 ways of initiation of translation to regulate gene expression

Answer 3

1. Binding of regulatory proteins at 5’UTR
2. Length of 3’ poly(A) tail
3. Presence of translation factors

Question 4

Explain rate of mRNA degradation

Answer 4

7-methylguanosine cap
-absence->increase the rate of mRNA degradation

presence of destabilising elements
-AU rich;
-binding of proteins that promote the shortening of poly(A) tail;
=>decrease the half life of mRNA

Question 5

Explain binding of regulatory proteins at 5’UTR

Answer 5

prevents the binding of small ribosomal subunit to 5’cap

Question 6

Explain length of poly(A) tail

Answer 6

determines the stability of mRNA

Question 7

Explain the presence of translation factors

Answer 7

chemical modification of translation factors can activate or inactivate the factors;

inactivated factors will prevent translation