Question

What is a solenoid?

• A. Nucleosomal organization with 10 nm thickness.
• B. Condensed chromatin fibre with 30 nm diameter.
• C. Highly condensed form of chromatid with 300 nm thickness.
• D. Well organised chromatid with 700 nm thickness.
• E. Well organised chromosome with 1400 nm thickness.

Answer 1

The correct option is B Condensed chromatin fibre with 30 nm diameter.

• DNA packaging is carried out to be wrapping the 166 bp of DNA around the core of the nucleosome. DNA connecting two adjacent nucleosomes is called linker DNA.
• The beads on the string arrangement of nucleosomes are approximately 10nm thickness, which is further condensed and coiled upon itself to produce a solenoid of a 30nm diameter.
• Hence, a solenoid is a structure of condensed chromatin fiber with a 30 nm diameter.
  

Thus, the correct answer is option B.