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

Step 1: Read the data.
The diploid chromosome number of the angiosperm is $2n = 36$, and we want the chromosome number of its endosperm.
Step 2: Recall how endosperm forms.
In angiosperms the endosperm comes from triple fusion during double fertilization.
Step 3: Understand triple fusion.
One haploid male gamete ($n$) fuses with the diploid secondary nucleus ($2n$), giving a triploid ($3n$) cell that becomes endosperm.
Step 4: Find the haploid number.
Since $2n = 36$, the haploid number is $n = \frac{36}{2} = 18$.
Step 5: Compute the triploid number.
Endosperm is $3n = 3 \times 18 = 54$.
Step 6: Conclude.
So the endosperm has $54$ chromosomes, which is option (4).
\[ \boxed{54} \]