The project 200 zygotes, how many meiotic divisions are required in flowering spermatocytes ?

Options

A. 125
B. 250
C. 300
D. 400

Answer

To solve the problem of how many meiotic divisions are required to produce 200 zygotes in flowering plants, we can break it down into steps:

### Step 1: Understand the Formation of Zygotes
- A zygote is formed by the fusion of two gametes: one male gamete and one female gamete. Therefore, to produce 200 zygotes, we need 200 male gametes and 200 female gametes.

### Step 2: Calculate Meiotic Divisions for Male Gametes
- In flowering plants, male gametes are produced through a process called microsporogenesis, which involves meiosis.
- One meiotic division in a diploid microspore mother cell produces four haploid microspores (male gametes).
- Therefore, to obtain 200 male gametes, we need to perform:
\[ \text{Number of meiotic divisions for male gametes} = \frac{200 \text{ male gametes}}{4 \text{ gametes per meiotic division}} = 50 \text{ meiotic divisions} \]

### Step 3: Calculate Meiotic Divisions for Female Gametes
- Female gametes are produced through a process called megasporogenesis, which also involves meiosis.
- One meiotic division in a diploid megaspore mother cell produces four megaspores, but only one of these megaspores develops into a functional female gamete (the other three degenerate).
- Therefore, to obtain 200 female gametes, we need to perform:
\[ \text{Number of meiotic divisions for female gametes} = 200 \text{ female gametes} = 200 \text{ meiotic divisions} \]

### Step 4: Total Meiotic Divisions
- Now, we can add the number of meiotic divisions required for both male and female gametes:
\[ \text{Total meiotic divisions} = 50 \text{ (for male)} + 200 \text{ (for female)} = 250 \text{ meiotic divisions} \]

### Conclusion
- Therefore, the total number of meiotic divisions required to produce 200 zygotes in flowering plants is **250**.