Question

If the diploid chromosome number of typical angiosperm is 36, what would be the chromosome number in its endosperm ?

• A. 72
• B. 18
• C. 36
• D. 54

Hint:

Angiosperm endosperm is triploid (\(3n\)) because of double fertilization. In contrast, the endosperm in gymnosperms is haploid (\(n\)) because it is formed before fertilization.

Answer 1

The Correct Option is D

Concept:

• In angiosperms, the endosperm is formed as a result of triple fusion (double fertilization).

• Triple fusion involves the fusion of one haploid male gamete (\(n\)) with the diploid secondary nucleus (\(2n\)) inside the embryo sac.

• This results in a triploid cell (\(3n\)) which develops into the endosperm tissue.

• Somatic cells (vegetative cells) of a typical angiosperm are diploid (\(2n\)).

Step 1: Find the haploid chromosome number
Given diploid number: \[ 2n = 36 \] Therefore, haploid number (\(n\)) is: \[ n = \frac{36}{2} = 18 \]

Step 2: Calculate the endosperm chromosome number
The endosperm is triploid (\(3n\)): \[ 3n = 3 \times 18 = 54 \] Thus, the chromosome number in its endosperm is \(54\).