Match List-I with List-II.
| List-I | List-II |
|---|---|
| A. Euchromatin | I. Densely packed and stains dark |
| B. Heterochromatin | II. Positively charged, basic proteins |
| C. Non-histone Chromosomal (NHC) proteins | III. Loosely packed and stains light |
| D. Histones | IV. Needed for packaging of chromatin at a higher level |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A-III, B-I, C-IV, D-II
In a eukaryotic nucleus DNA is packed with proteins. Histones form the nucleosome, while a further set of proteins packs chromatin at a higher level. The packed chromatin is also not uniform: some parts are loose and some are dense.
(A) Euchromatin — this matches (III) Loosely packed and stains light. It is the transcriptionally active chromatin.
(B) Heterochromatin — this matches (I) Densely packed and stains dark. It is transcriptionally inactive.
(C) Non-histone Chromosomal (NHC) proteins — this matches (IV) Needed for packaging of chromatin at a higher level.
(D) Histones — this matches (II) Positively charged, basic proteins. They are rich in lysine and arginine.
The correct code is A-III, B-I, C-IV, D-II.
NCERT Extract:
Packaging of DNA Helix – “… The packaging of chromatin at higher level requires additional set of proteins that collectively are referred to as Non-histone Chromosomal (NHC) proteins. In a typical nucleus, some region of chromatin are loosely packed (and stains light) and are referred to as euchromatin. The chromatin that is more densely packed and stains dark are called as Heterochromatin.”
Packaging of DNA Helix – “… There is a set of positively charged, basic proteins called histones. A protein acquires charge depending upon the abundance of amino acids residues with charged side chains.”