Regulation of Gene expression

Question 1

Regulation of gene expression in prokaryotes involves ….. or ….. of transcription

Answer 1

initiation or termination

Question 2

Define bacterial Operon and where is it located?

Answer 2

It is a set of structural gene plus a regulatory region which is located upstream (5’ side) of the structural gene.

Question 3

In an Operon, the expression of all structural gene is regulated by …..

Answer 3

the same regulatory region in the DNA

see p.389

Question 4

A polycistronic mRNA is ….

Answer 4

an mRNA that codes for more than one protein. It is found only prokaryotes

Question 5

The repressor in lac operon is made …..

Answer 5

constitutively (ie. depending on presence of lactose)

see p. 389

Question 6

In lac operon, the repressor binds to …… and prevents ……. . This is called …. regulation

Answer 6

operator region
the movement of RNA polymerase along the template
negative

Question 7

In lac operon, the absence of glucose increases ……, which in turn binds to ….., this complex binds to the promoter region on lac operon and increase transcription

Answer 7

cAMP

CAP (catabolite activator protein)

Question 8

cAMP-CAP complex is a ….. of lac operon

Answer 8

positive regulator

Question 9

Full transcription of lac operon requires …. & ….

Answer 9

1. absence of repressor

2. presence of activatore