In mitosis, each chromosome splits longitudinally and appear as two chromatids for the first time in

Options

A. Early metaphase
B. Mid prophase
C. Plane of alignment of chromosomes at equator
D. Telophase

Answer

To solve the question regarding when each chromosome splits longitudinally and appears as two chromatids for the first time during mitosis, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Phases of Mitosis**: Mitosis consists of several phases: prophase, metaphase, anaphase, and telophase. Each phase has distinct events that occur.

2. **Identify Key Events in Prophase**: During prophase, chromosomes condense and become visible. This is the stage where the chromatin fibers coil and shorten, leading to the formation of distinct chromosomes.

3. **Recognize the Formation of Sister Chromatids**: As the chromosomes condense during prophase, each chromosome replicates to form two identical sister chromatids. This splitting occurs longitudinally, meaning that each chromosome is now represented as two chromatids.

4. **Differentiate Between Early and Mid-Prophase**: In early prophase, the chromosomes are beginning to condense, but they may not yet be fully visible as two separate chromatids. It is in mid-prophase that the chromosomes are clearly seen as two distinct sister chromatids.

5. **Evaluate Other Phases**:
- **Metaphase**: Chromosomes align at the cell's equatorial plane, but they are already in the form of chromatids, so this is not the first appearance.
- **Anaphase**: The sister chromatids are pulled apart, which is after they have already appeared.
- **Telophase**: Chromosomes de-condense and are no longer visible as distinct chromatids.

6. **Conclusion**: The first time chromosomes split longitudinally and appear as two chromatids is during **mid-prophase**.

### Final Answer:
The correct answer is **mid-prophase**.

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