Chromosomal organisation

Question 1

Name 3 constituents inside the nucleus

Answer 1

• DNA
• RNA
• nucleoprotein (histone/non-histone)

Question 2

How does DNA fit in the nucleus?

Answer 2

• DNA is organised in linear structures called chromosomes.
• Structural proteins and chaperones prevent DNA from
  getting tangled.
• Before cell division, chromosomes are duplicated: each copy is called a chromatid.
• Chromatids are held together at the centromere.

Question 3

DNA packing

Answer 3

• 46 units of linear double stranded DNA polymer
• 22 pairs of autosomes (Ch1-22)
• 1 pair of sex chromosomes (XX / XY)

Question 4

Karyotype

Answer 4

The characterization of the chromosomal complement of an individual or a species, including number, form, and size of the chromosomes

Question 5

Centromere

Answer 5

area of condensed chromatin that separates the chromosome into 2 arms

Question 6

Kinetochore

Answer 6

large protein assembly that connect chromosomes to microtubules of the mitotic and meiotic spindles in order to distribute the replicated genome from a mother cell to its daughters

Question 7

Supercoiling

Answer 7

• DNA supercoiling: over and under winding of a DNA strand
• Compacts DNA
• Regulates gene expression

Question 8

Name the 7 levels of DNA supercoiling

Answer 8

1. Double helix
2. Nucleosome
3. Chromatosome
4. Soleniod
5. 30nm fibre
6. Chromatin
7. Chromosome