Question

To explain the structure of dna, the author talks about a pearl necklace. How do these pearl necklaces vary from one individual to another

Answer 1

actually you can associate this with dna fingerprinting as some base pair are same on everyone the actual variation arise from every repeation this small variation after no of chains are different in each other
this structure are called as solenoid structure ....and you can refer it with histone octamer in ncert....
hope this will help you ..

Answer 2

Answer:

The arrangement of DNA in the chromosome has been described as beads on a string or pearl necklace denoting the wrapping of DNA around a core of histone octamer. These differ from individual to individual in the sequence of genetic segments on the DNA strands.

Explanation:

• The DNA is a semi-helical molecule, consisting of two strands running in anti-parallel directions.
• The DNA strand consists of Deoxyribose sugar, phosphate groups and nitrogenous bases- adenine, guanine, thymine and cytosine.
• The DNA strand wraps around a core of histone molecules called the octamer by making 1.75 turns.
• Such an arrangement is called a beads on a string appearance.