Organization Of DNA

Question 1

What is supercoiling

Answer 1

The way of DNA organisation in mitochondria and procaryotes.
Negatively supercoiled dna - dna wound more loosely that watson-crick dna
Positively - dna wound more tightly

Question 2

What enzyme can change the amount of supercoiling?

Answer 2

Topoisomerase

Question 3

Histones are rich in —

Answer 3

Lysine and arginine

Question 4

Histone octomer consist of

Answer 4

H2a
H2b
H3
H4
X2

Question 5

What is nucleosome

Answer 5

DNA is wound around the octamer. The basic packaging unit of chromatine

Question 6

What size is the nucleosome

Answer 6

10 nm

Question 7

What is the role of H1

Answer 7

It bounds the nucleosomes between each other and packs them into solenoid structure (30 nm)

Question 8

Whats chromatine

Answer 8

Dna assosiated with proteins (histones and non-histones)

Question 9

What types of chromatine does cell in interphase contain?

Answer 9

Euchromatine and heterochromatine

Question 10

Differences between eu- and heterochromatine

Answer 10

HETERO:

• dark-staining
• contains inactive genes
• highly condensed
• ex: Barr bodies

EU:

• light-staining
• contains active genes
• packed loosely
• ex: apoptosis genes

Question 11

Resistance of a 10 nm particle and 30 nm particle

Answer 11

10 nm more sensitive to nucleases

30 nm is more resistant

Question 12

Levels of DNA packaging

Answer 12