DNA packaging

Question 1

How do prokaryotic cells divide

Answer 1

fission

Question 2

fission

Answer 2

1. they have one circular chromosome
2. as DNA replicates it attaches to membrane
3. new plasma membrane between attached points
4. Cytokinesis separates the one cell into two

Question 3

How do eukaryotes divide

Answer 3

mitosis , meiosis

Question 4

constriction point of a chromosome

Answer 4

centromere

Question 5

arms of chromosome

Answer 5

short - p arm
long - q arm

Question 6

Chromatin

Answer 6

DNA + Histone + other proteins making up chromosomes

Question 7

What energy is needed for coiling

Answer 7

Histones provide energy

Question 8

What is a histone

Answer 8

positively charged protein, that DNA is compact chromosomal DNA

Question 9

charge of DNA

Answer 9

negative due to phosphate groups in its phosphate sugar backbone

Question 10

Nucleosome

Answer 10

repeating structural and functional unit of chromatin
- 9 histones, 166 base pairs

Question 11

functions of chromatin

Answer 11

• package DNA
• strengthen DNA for division
• control gene expression and replication

Question 12

Two forms chromatin is divided between

Answer 12

Heterochromatin (condensed)
Euchromatin (Extended)

Question 13

Two mechanisms by which chromatin is made more accessible

Answer 13

• histones enzymatically modified
• histones displaced by chromatin remodelling complexes
  = reversible

Question 14

Prometaphase

Answer 14

Nuclear envelop breaks down
microtubules attach to chromosome

Question 15

Metaphase

Answer 15

chromosomes line up in the centre on the metaphase plate
spindle fibres are attached