If primary, spermatocyte have 2n = 16 chromosomes during first meiotic division, in this case how many chromatids could be present in each secondary spermatocyte?

Options

A. 32
B. 8
C. 24
D. None of these

Answer

To solve the problem of how many chromatids are present in each secondary spermatocyte when the primary spermatocyte has 2n = 16 chromosomes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Chromosome Number**:
- The primary spermatocyte is diploid (2n), meaning it has two sets of chromosomes. Given that 2n = 16, this means the primary spermatocyte has 16 chromosomes.

2. **Meiosis Overview**:
- Meiosis consists of two divisions: Meiosis I and Meiosis II. The first division (Meiosis I) separates homologous chromosomes, while the second division (Meiosis II) separates sister chromatids.

3. **Meiosis I Outcome**:
- During Meiosis I, the primary spermatocyte (2n = 16) undergoes division. After this division, the result is two secondary spermatocytes, each of which is haploid (n).

4. **Calculate Chromosome Number in Secondary Spermatocytes**:
- Since the primary spermatocyte had 16 chromosomes (2n), after Meiosis I, each secondary spermatocyte will have half that number, which is 8 chromosomes (n = 8).

5. **Chromatid Count**:
- Each chromosome at this stage consists of two sister chromatids (because DNA replication occurs before meiosis). Therefore, if there are 8 chromosomes in each secondary spermatocyte, and each chromosome has 2 chromatids, the total number of chromatids in each secondary spermatocyte is:
\[ \text{Total chromatids} = \text{Number of chromosomes} \times 2 = 8 \times 2 = 16 \]

6. **Final Answer**:
- Each secondary spermatocyte contains 16 chromatids.

### Summary:
- Each secondary spermatocyte has **16 chromatids**.