Question

In apple, the chromosome number of gametes is 17. What is the chromosome number in its Primary Endosperm Nucleus (PEN)?

• A. 51
• B. 34
• C. 68
• D. 17

Hint:

Always identify the ploidy of the tissue mentioned: Gamete ($n$), Zygote/Somatic cell ($2n$), and Endosperm ($3n$). In some gymnosperms, endosperm is haploid, but in angiosperms (like apple), it is always triploid.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
In flowering plants, gametes are always haploid ($n$). The Primary Endosperm Nucleus (PEN) is formed through triple fusion, which is the fusion of two polar nuclei and one male gamete, resulting in a triploid ($3n$) structure.
Step 2: Key Formula or Approach:
1. Chromosome number in gamete = $n$.
2. Chromosome number in PEN = $3n$.
Step 3: Detailed Explanation:
1. Given: Haploid number ($n$) = 17. 2. The PEN is triploid ($3n$). 3. Calculation: $3 \times 17 = 51$.
Step 4: Final Answer
The chromosome number in the Primary Endosperm Nucleus (PEN) of apple is 51.