Riya R.

🔁 **CELL CYCLE** has two main phases:

1. **Interphase** (preparation for division)

2. **M Phase (Mitotic phase)** (actual division happens)

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## ✅ **1. INTERPHASE** (90% of cell cycle)

Interphase has 3 stages:

### 👉 **G₁ phase (Gap 1)**

* Cell grows in size

* Makes proteins and organelles

* Prepares for DNA replication

> 📌 *Checkpoint: Is the cell ready to copy DNA?*

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### 👉 **S phase (Synthesis)**

* **DNA is replicated** (copied)

* Each chromosome becomes **two sister chromatids**

> 📌 *Chromosomes are duplicated here*

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### 👉 **G₂ phase (Gap 2)**

* Final preparations for division

* Cell makes proteins needed for mitosis

> 📌 *Checkpoint: Any DNA damage? Ready to divide?*

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## ✅ **2. M PHASE (Mitotic Phase)**

This is where the **cell divides**. It has **2 parts**:

1. **Mitosis** – Division of the nucleus

2. **Cytokinesis** – Division of the cytoplasm

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### Mitosis has 4 main stages:

### 👉 **Prophase**

* Chromosomes condense and become visible

* Nuclear membrane breaks down

* Spindle fibers form

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### 👉 **Metaphase**

* Chromosomes line up in the **middle** of the cell

* Spindle fibers attach to centromeres

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### 👉 **Anaphase**

* Sister chromatids **separate**

* They move to **opposite sides** of the cell

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### 👉 **Telophase**

* Nuclear membranes **re-form** around each group of chromosomes

* Chromosomes uncoil back to chromatin

* Spindle fibers disappear

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### ✂️ **Cytokinesis**

* Cytoplasm divides

* Two daughter cells are formed