All of the following has 46 chromosomes except?

Options

A. Spermatogonia
B. Zygote
C. Secondary oocyte
D. Oogonia

Answer

To solve the question "All of the following has 46 chromosomes except?", we will analyze each option provided:

1. **Spermatogonia**:
- Spermatogonia are the primordial male germ cells.
- They are diploid (2n), meaning they contain two sets of chromosomes.
- Therefore, they have a total of 46 chromosomes.

2. **Zygote**:
- A zygote is formed by the fusion of male and female gametes (sperm and egg).
- Both gametes are haploid (n), containing 23 chromosomes each.
- When they fuse, the zygote becomes diploid (2n) and thus has 46 chromosomes.

3. **Secondary Oocytes**:
- Secondary oocytes are formed during oogenesis, which is the process of egg formation.
- They are produced from primary oocytes through meiosis, which is a reductional division.
- As a result, secondary oocytes are haploid (n) and contain only 23 chromosomes.

4. **Oogonia**:
- Oogonia are the primordial germ cells in females.
- Similar to spermatogonia, they are diploid (2n) and have 46 chromosomes.

Now, summarizing the findings:
- Spermatogonia: 46 chromosomes (diploid)
- Zygote: 46 chromosomes (diploid)
- Secondary Oocytes: 23 chromosomes (haploid) - **This is the exception**
- Oogonia: 46 chromosomes (diploid)

**Final Answer**: The option that does not have 46 chromosomes is **Secondary Oocytes**.