In onion root tip during mitotic metaphase, the number of kinetochores is

Options

A. 4
B. 64
C. 32
D. 16

Answer

To determine the number of kinetochores in the onion root tip during mitotic metaphase, follow these steps:

### Step-by-Step Solution:

1. **Identify the Number of Chromosomes in Onion Root Tip Cells**:
- Each somatic cell of an onion root tip contains **8 chromosomes**.

2. **Understand the Process of Cell Division**:
- Before a cell undergoes mitosis, it duplicates its chromosomes during the S phase of interphase. Thus, when a cell is preparing for mitosis, it has **duplicated its chromosomes**.

3. **Calculate the Total Number of Chromosomes at Metaphase**:
- Since the original number of chromosomes is 8 and they are duplicated, the total number of chromosomes during metaphase is:
\[ 8 \text{ (original)} \times 2 = 16 \text{ chromosomes} \]

4. **Determine the Number of Kinetochores**:
- Each chromosome has **2 kinetochores** (one at each centromere).
- Therefore, to find the total number of kinetochores during metaphase, multiply the number of chromosomes by the number of kinetochores per chromosome:
\[ 16 \text{ chromosomes} \times 2 \text{ kinetochores/chromosome} = 32 \text{ kinetochores} \]

5. **Conclusion**:
- The number of kinetochores in the onion root tip during mitotic metaphase is **32**.

### Final Answer:
The number of kinetochores in the onion root tip during mitotic metaphase is **32**.

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