Question

Wheat plant is \[6n = 42\]. What will be the number of chromosomes in its monosomic, haploid and monoploid?
A) $43,21,7$
B) $41,21,7$
C) $15,7,7$
D) $13,7,7$

Answer 1

Hint: A human cell as we know is diploid which means that it has two copies of twenty-three chromosomes for a total of forty-six chromosomes, whereas in the case of a wheat cell which is considered to be a hexaploid has six copies of its seven chromosomes which means that it has forty-two chromosomes in total.

Complete answer:
A genome is all of a living thing's genetic material, which is the entire set of instructions for the creation and function of an organism. Wheat has the largest genome among the commonly grown agricultural crops.

Monosomic means a cell missing a single chromosome. Trisomies and monosomies are types of chromosomal abnormalities. Trisomy is when there are three of a particular chromosome, instead of the usual two whereas monosomy is when they have one chromosome instead of the usual two. Hence, we can calculate it as \[42 - 1 = 41\]
Haploid stands for half the number of chromosomes, therefore we can calculate haploid stage as \[\dfrac{42}{2} = 21\]
Monoploid means a cell or an organism that has a single set of chromosomes where each set is identified as n. Here
\[
  n =\dfrac{42}{6}{\text{ }} \\
  {\text{n = 7}} \\
\]

So, the correct answer is option ‘B’ which states that the number of chromosomes in monosomic, haploid and monoploid stages of wheat stand for $41,21,7$.

Note: The polyploidy in wheat is necessary because it influences some of the plant features and also, wheat with one ploidy level will be more closely related to each other, therefore no new genes will be introduced into the species. It is found that hexaploid wheat is produced by crossing tetraploid wheat with a diploid one.