NEETZoologyMolecular Basis of Inheritance
How is a long polymer like DNA packaged in a cell?
Options
- AScattered throughout the cell
- BHeld with some proteins in a region called ‘nucleoid’
- COutside the cell
- DIn the nucleus
Correct answer
B. Held with some proteins in a region called ‘nucleoid’
Step-by-step solution
Taken the distance between two consecutive base pairs as 0.34 nm (0.34×10–9 m), if the length of DNA double helix in a typical mammalian cell is calculated (simply by multiplying the total number of bp with distance between two consecutive bp, that is, 6.6 × 109 bp × 0.34 × 10-9m/bp), it comes out to be approximately 2.2 meters. A length that is far greater than the dimension of a typical nucleus (approximately 10–6 m). How is such a long polymer packaged in a cell? If the length of E. coli DNA is 1.36 mm, can you