Histones are rich in amino acids:
(1) Arginine and Lysine
(2) Argine and Leucine
(3) Arginine and Isoleucine
(4) Aspartate and Glutamate
Go through the following diagram of Nucleosome (structural unit of chromatin). Identify its componential parts indicated by A, B and C:
A | B | C | |
(1) | RNA | Non histone | Histone |
(2) | DNA | H1 histone | Histone Octamer |
(3) | RNA | Histone Octamer |
H1 histone |
(4) | DNA | Non histone | Histone |
A typical nucleosome unit consists of about:
1. 60 base pairs
2. 140 base pairs
3. 200 base pairs
4. 400 base pairs
What are those structures that appear as ‘beads-on-string’ in the chromosomes when viewed under electron microscope?
(1) Nucleotides
(2) Nucleosomes
(3) Base pairs
(4) Genes
Heterochromatin:
A. Is more densely packed B. Is stains dark
C. Is transcriptionally active D. Is transcriptionally inactive
(1) A, C
(2) A, B, C, D
(3) B, C, D
(4) A, B, D
The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommodated?
(1) Deletion of non essential genes
(2) Super-coiling in nucleosomes
(3) DNAse digestion
(4) Through elimination of repetitive DNA
Transcriptionally active chromatin is termed as:
1. Heterochromatin
2. Euchromatin
3. Prechromatin
4. Prochromatin
The association of histone H1 with a nucleosome indicates
(1) transcription is occuring
(2) DNA replication is occuring
(3) the DNA is condensed into chromatin fibre
(4) the DNA double helix is exposed
The length of E. coli DNA and length of DNA in a human 2N cell is:
(1) 1.36 mm and 2.2 m respectively
(2) 1.36 mm and 2.2 mm respectively
(3) 1.3 ìm and 2.2 ìm respectively
(4) 1.36 cm and 2.2 cm respectively
During DNA packaging in eukaryotic cells, Non Histone Chromosomal proteins:
1. Are not required
2. Are required from the beginning to the end of packaging
3. Are required only for earlier stages of packaging
4. Are required for higher level of packaging