Question

जापापहासमा प्रश्नाक अक
11464 81
1. Fill in the blanks :
(a) Separation of the two strands of the DNA helix on heating is
called ....DHA.... denaturation:
(b) Based on renaturation kinetics, the DNA can be classified into ..........,
........... and sequences.
(c) DNA sequences which have the unique ability to move as discrete
units from one position in the genome to another are called ..
(d) Method of hybridizing DNA to nitrocellulose bound single stranded
DNA is known as
(d) The enzyme required for the synthesis of cDNA from mRNA is .....
(f) .......... and ............... studied the E.coli lactose system and gave the
................ for requiration of gene expression in prokaryotes.
(g) ............. found as extrachromosomal circular DNA molecules in most
bacteria can be used as.............. in Recombinant DNA technology.
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Answer 1

Answer:

DNA molecules are tightly wound around proteins - called histone proteins - which provide structural support and play a role in controlling the activities of the genes. A strand 150 to 200 nucleotides long is wrapped twice around a core of eight histone proteins to form a structure called a nucleosome. The histone octamer at the centre of the nucleosome is formed from two units each of histones H2A, H2B, H3, and H4. The chains of histones are coiled in turn to form a solenoid, which is stabilised by the histone H1. Further coiling of the solenoids forms the structure of the chromosome proper.