Question

The number of chromosomes in a somatic cell, of a diploid organism (with original of 10 pairs), after DNA replication and before mitosis would be
A. 10
B. 20
C. 30
D. 40
E. 50.

Answer 1

Hint: After DNA replication, every chromosome now includes bodily connected sister chromatids. After chromosome condensation, the chromosomes condense to shape compact structures.

Complete answer:
To answer this question, first, we need to know about chromosomes. When a cell divides, one in all its major jobs is to ensure that every of the 2 new cells receive a full, best replica of the genetic element. Mistakes for the duration of copying, or unequal dividing of the genetic element among cells, can result in cells which might be dangerous or dysfunctional (and can result in sicknesses which include cancer).
Now, let us find the solution from the option.
The somatic cell has 20 chromosomes (10 pairs). DNA replication doubles the DNA content material that is accommodated in chromatids of every chromosome. The general quantity of chromosomes stays identical. So, the given cell with 20 chromosomes may have the identical quantity of chromosomes after DNA replication and earlier than mitosis.
After DNA replication and earlier than mitosis, the quantity of chromosomes in somatic cell is not more than or less than 20, it is specific 20.

Hence, the correct answer is option (B)

Note: Human somatic cells have 46 chromosomes inclusive of units of twenty-two homologous chromosomes and 2 nonhomologous intercourse chromosomes. This is the 2n, or diploid, state. Human gametes have 23 chromosomes or one entire set of chromosomes however earlier than and after DNA replication it has 20 chromosomes.