Question

If a diploid cell is treated with colchicines, then it becomes
A. Tetraploid
B. Diploid
C. Triploid
D. Monoploid

Answer 1

Hint: The cells in the body are made by the mitosis and meiosis. They will reduce the genetic content in them to make them less in ploidy. Meiosis occurs after fertilization has taken place. This helps in the division of cells to form the gametes or cells for the next generation. The reduction of genetic material will take place.

Complete answer: Colchicine is an alkaloid from seeds of Colchicum autumnale. It has the unique property of arresting the spindle formed in the cell division process.
Colchicine will inhibit the formation of microtubules involving the spindle fibres formation. This is an important step to divide the chromosomes into two daughter cells.
If the microtubules are not formed, the genetic material will not be distributed to the daughter cells. The metaphase stage will become dormant and hence, the diploid cell will have twice the number of chromosomes. Thus it will have a tetraploid cell.
Option A: Tetraploid: The cell having the 46 pairs of the chromosome is tetraploid. It is formed when there is some obstruction while the reduction of the chromosome number.
Option B: Diploid: The normal cell of a human being is diploid having 23 pairs of chromosomes.
Option C: Triploid: The triploid cell is like the endosperm which will have 69 number of chromosomes.
Option D: Monoploid: Half of the chromosome pairs make the monoploid cell.
So the answer is option A: Tetraploid

Note: Anaphase 1 initiates when the two chromosomes of tetrad separate. Their movement towards the pole is the characteristic feature. The sister chromatids remain attached and their pairs move to the poles. They are joined at the centromere. Here the reduction of chromosome pairs takes place.