During mitotic cycle what occurs first?

Options

A. Cytoplasmic division
B. Spindle formation
C. Movement of chromosomes
D. Chromosome duplication

Answer

To determine what occurs first during the mitotic cycle, we need to analyze the stages of mitosis and the events leading up to it. Here’s a step-by-step breakdown of the process:

### Step 1: Understand the Mitotic Cycle
The mitotic cycle includes several phases: Interphase (which includes G1, S, and G2 phases) and M phase (mitosis and cytokinesis). M phase is where cell division occurs.

**Hint:** Remember that the mitotic cycle consists of interphase and the M phase, where mitosis takes place.

### Step 2: Identify the Stages of Mitosis
Mitosis itself is divided into several stages:
- Prophase
- Metaphase
- Anaphase
- Telophase

**Hint:** Familiarize yourself with the stages of mitosis and what happens in each stage.

### Step 3: Analyze the Options
The options given are:
1. Cytoplasmic division
2. Spindle formation
3. Movement of chromosomes
4. Chromosome duplication

**Hint:** Consider the sequence of events that occur during mitosis and what happens before it.

### Step 4: Determine the Sequence of Events
- **Chromosome Duplication:** This occurs during the S phase of interphase, before mitosis begins. However, it is not part of the mitotic cycle itself.
- **Spindle Formation:** This occurs during prophase, which is the first stage of mitosis.
- **Movement of Chromosomes:** This occurs during metaphase and anaphase, which are subsequent stages.
- **Cytoplasmic Division:** This occurs after mitosis, during cytokinesis.

**Hint:** Focus on the events that occur specifically during the mitotic phase.

### Step 5: Conclusion
The first event that occurs during the mitotic cycle is **spindle formation**, which takes place in prophase.

**Final Answer:** Spindle formation occurs first during the mitotic cycle.

---