Question
Biology Question on Structure of DNA and RNA
Read the following statements and select the correct option. (i) Loosely packed and lightly stained region of chromatin are called as heterochromatin. (ii) Densely packed and dark stained region of chromatin are called as euchromatin. (iii) A typical nudeosome contains 200 bp of DNA helix
Statements (i) and (ii) are true, but statement (iii) is false
Statements (i) and (ii) are false, but statement (iii) true
Statements (ii) and (iii) are true, but statement (iv) false
All the statements are true
Statements (i) and (ii) are false, but statement (iii) true
Solution
A typical nudeosome contains 200bp of DNA helix. Nudeosomes constitute the repeating unit of a structure in nucleus called chromatin. Chromatin is held over a scaffold of non-histone chromosomal (or NHC) proteins. At some places chromatin is densely packed to form darkly stainined heterochromatin. At other places chromatin is loosely packed. It is called euchromatin. It is transcriptionally active chromatin whereas heterochromatin is transcriptionally inactive and late replicating or heteropycnotic.