The chromosome number of a spore mother cell of an angiosperm is 38. What will be chromosome number of its endosperm cell?

Options

A. 38
B. 19
C. 57
D. 76

Answer

To determine the chromosome number of the endosperm cell in an angiosperm when the chromosome number of a spore mother cell is given as 38, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Chromosome Number of the Spore Mother Cell**:
- The spore mother cell (also known as the microsporocyte) has a diploid chromosome number, which is given as 38. This means it is represented as 2N = 38.

2. **Determine the Haploid Number of Spores**:
- Since the spore mother cell is diploid (2N), the spores produced from it will be haploid (N). To find the haploid number, we divide the diploid number by 2:
\[ N = \frac{2N}{2} = \frac{38}{2} = 19 \]
- Therefore, the haploid number (N) is 19.

3. **Understand the Formation of Endosperm**:
- The endosperm is formed through a process called triple fusion during fertilization. In this process, one male gamete fuses with two polar nuclei.

4. **Calculate the Chromosome Number of the Endosperm**:
- The endosperm is triploid (3N) because it is formed from the fusion of one haploid male gamete (N = 19) and two polar nuclei (also contributing to the chromosome count).
- Thus, the chromosome number of the endosperm can be calculated as:
\[ 3N = 3 \times 19 = 57 \]

5. **Conclusion**:
- The chromosome number of the endosperm cell is 57.

### Final Answer:
The chromosome number of the endosperm cell is **57**.

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