Role Of Chromatin Structure In Gene Control

Question 1

Drosophila eye colour is encode by ………… …………..

Answer 1

White gene responsible for the normal red pigmentation of the eyes of adult flies

Question 2

What is variegation?

Answer 2

Is seen in some cases when a gene is moved into a region of heterochromatin

Question 3

Inactivated …………… Gene produces ………….. Eyes

Answer 3

White

White

Question 4

When inserted into…………. ,Expression of the White gene becomes………………… Producing eyes with …………… And ……………. Red pigmentation

Answer 4

Heterochromatin
Variegated
Salt and pepper

Question 5

Inversion of white gene resulted in…………… Of gene next to the ………………….. ……… Gene silenced to ……….. ……… By spread of heterochromatin. Resulted in some………. Having active or inactive ……….. ………

Answer 5

Positioning
Heterochromatic DNA
Cells
Heterochromatin

Question 6

DNA wrapped around………… To form ………. …. …. ……… Further compacted in…….. Fibre ……. …… ………. Compacted again to form……………

Answer 6

Histones
Beads on string 
30nm 
Zig zag structure
Heterochromatin

Question 7

Histone structure

Answer 7

147bp of DNA wrapped around histones to form nucleosome

Question 8

Core histones made of

Answer 8

Two copies of
H2A, H2B, H3 and H4
One molecule of H1 per nucleosome

Question 9

Histone variants:

Answer 9

CENP-A replaces H3 in nucleosomes of the centromere

H2A.X is a histone variant found,It makes a central contribution to genome stability through its role in the signaling of DNA damage events

Question 10

H2AX

Answer 10

Phosphorylation of H2AX plays a key role in DNA damage response (DDR) and is required for the assembly of DNA repair proteins at the sites containing damaged chromatin