REGULATION OF GENE EXPRESSION & DNA FINGERPRINTING

Question 1

regulation of gene in eukaryotes can be done at which levels

Answer 1

⬛ transcriptional level - formation of primary transcript
⬛ processing level - splicing
⬛ transfer of mRNA from nucleus to cytoplasm
⬛ translational level

Question 2

what is beta galactosidase? use?

Answer 2

enzyme synthesised by E.coli
catalyse the hydrolysis of a disaccharide - lactose to galactose and glucose
used as a source of energy

Question 3

give an example for gene regulation in adult organisms

Answer 3

development and differentiation of embryo

Question 4

predominant site for gene regulation in prokaryotes

Answer 4

control rate of transcriptional initiation

Question 5

operators

Answer 5

interactive proteins used for regulation (accessablity of promoter regions) in prokaryotes

Question 6

where is the operator region present

Answer 6

adjacent to the promoter elements OR binding the repressor protein

Question 7

regulatory proteins?
types?

Answer 7

regulate the activity of rna polymerase - affect its ability to recognise start sites

activators (act +vly)
repressors (act -vly)

Question 8

lac operon was found by

Answer 8

Jacob And Monod

Question 9

operon arrangements?
eg?

Answer 9

polycistronic structural gene is regulated by a common promoter and regulatory genes

lac trp ara his val

Question 10

components of lac operon

Answer 10

regulatory gene: i gene OR inhibitor gene- codes for repressors

structural gene:
z gene - codes for Bgalactosidase
y gene - codes for permease (inc permeability of cell to Bgal)
a gene - codes transacetelylase

Question 11

inducer in lac operon

Answer 11

lactose - substrate for Bgalactosidase
regulate on and off of the operon

OR allolactose

Question 12

why a very low level of expression of lac operon has to be present in the cell all time

Answer 12

otherwise lactose cannot enter the cells

Question 13

lac operon functioning

Answer 13

⚫i gene synthesis repressor all the time
⚫repressor protien binds to the operator region of the operon and prevents rna polymerase from transcribing the operon
⚫in the presence of inducer repressor is inactivated by interaction with the inducer
⚫this allows rna polymerase access the inducer and transcription proceeds

Question 14

property behind lac operon

Answer 14

regulation of enzyme synthesis by its substrate

Question 15

negative regulation

Answer 15

regulation of lac operon by repressor

Question 16

how dna finger printing is the basis of paternity testing

Answer 16

as polymorphism is inheritable from parents to children

Question 17

polymorphism?
reason?

Answer 17

variation at genetic level

arise due to mutations

Question 18

basis of genetic mapping of human genome and dna fingerprinting

Answer 18

polymorphism

Question 19

dna polymorphism

Answer 19

inheritable mutation due to germ cell mutation

Question 20

who developed the dna fingerprinting technique

Answer 20

Alec Jeffreys

Question 21

VNTR

Answer 21

variable number of tandem repeats

mini satellite dna probe used by jeffreys

Question 22

sensitivity of dna fingerprinting technique is increased by the use of

Answer 22

polymerase chain reaction

Question 23

uniqueness of autodiagram on dna fingerprinting technique shows exception in the case of

Answer 23

monozygotic twins (identical)