Shaiha

What is the Cell Cycle?

The cell cycle is the series of events a cell goes through to grow and divide into two new cells.

It has two major phases:

1. Interphase – The cell prepares to divide

2. M phase (Mitotic Phase) – The cell actually divides

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🔹 1. INTERPHASE (Preparation Phase)

Interphase is the longest phase, where the cell grows and gets ready to divide.

It is divided into 3 stages:

🟢 G1 Phase (Gap 1)

The cell grows in size

Makes proteins and organelles

Very active stage (but no DNA copying yet)

📝 Think: Grow First

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🔵 S Phase (Synthesis)

The cell copies its DNA

Now the cell has double the genetic material

📝 Think: S = Synthesize = DNA copying

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🟣 G2 Phase (Gap 2)

Cell prepares for division

Makes enzymes needed for mitosis

Checks for DNA errors

📝 Think: Get ready to Go!

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🔸 2. M PHASE (Mitosis)

Now the cell actually divides into two identical daughter cells.

M phase has two parts:

Mitosis (division of nucleus)

Cytokinesis (division of cytoplasm)

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🌟 Mitosis is divided into 4 stages:

🟠 Prophase

Chromosomes become visible

Nuclear membrane breaks down

Spindle fibers start to form

📝 Think: Prepare the chromosomes

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🟡 Metaphase

Chromosomes line up in the middle of the cell

Spindle fibers attach to them

📝 Think: M = Middle

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🟢 Anaphase

Spindle fibers pull the chromosomes apart

Each side gets equal halves

📝 Think: A = Away

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🔵 Telophase

Nuclear membrane reappears

Two new nuclei form

Cell starts to pinch

📝 Think: T = Two nuclei

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🟤 Cytokinesis (Final Step)

The cell’s cytoplasm splits

Two identical cells are formed

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🌈 Summary Table:

Phase What Happens?

G1 Cell grows

S DNA copied

G2 Cell prepares for division

Prophase Chromosomes visible, spindle forms

Metaphase Chromosomes line up in center

Anaphase Chromosomes pulled apart

Telophase Two nuclei form

Cytokinesis Cell splits into two