Question

A chromatin fibre of 40 nm length contains 25 nucleosom. The degree of compaction of dna associated with this chromatin fibre is ?

Answer 1

In eukaryotes, DNA is tightly packed with histone protein, which forms the an array of DNA  called nucleosomes. each 200 nucleotide sequence of dna is bound with histone to form nucleosome. while 40nm chromatin fiber contains 25 nucleosomes. so degree of compaction of DNA  with this chromatin fiber is approximately 27 folds.

Answer 2

Answer:

As one nucleosome has 200 base pair

length of one nucleosome is 200×0.34= 68nm (no. of base pair × distance between each base pair)

so, length of 25 nucleosome= 25×68= 1700nm

Therefore compaction is; 1700/40 = 42.5 folds.