Nuclosomes are -

Ans. is 'b' i.e., DNA+Histones o Nucleosomes are primary structural units of chromatin.o It consists of DNA bound to protein histonesQ, i.e. core of protein histones wrapped with DNAQ.o Histones are basic proteins rich in lysine and argininine2.o These positively charged amino acids interact with negatively charged phosphate group of DNA.o There are five types of histones HI, H2A, H2B, H3 and H4.o Two molecules of each H2A, H2B, H3 and H4 associate one another to form histone octomer.o Around histone octomer a segment of the DNA helix is wound nearly twice forming nucleosome core.o A nucleosome associated with histone H1 is called chromatosome.o A series ofnucleosome ("beads on a string") form a polynucleosome or chromatin.o The DNA connecting two nucieosomes is called linker (or spacer) DNA. To linker DNA, HI histone is attached to stabilize the complex.o Non-histone proteins are also attached to linker DNA.o These repeating units of nucieosomes, connected with linker DNA, form chromatin fiber.