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The Cell Cycle & Cell Division

Most cells in an organism go through a cycle of growth, development, and division called the cell cycle.

The cell cycle allows organisms :

to grow and develop replace old or

damaged cells produce new cells.

The Cell Cycle

There are two main phases of the cell cycle:1. Interphase 2. Mitotic phase

Phases Of The Cell Cycle

Interphase is a period of growth and development for a cell.

It makes up most of the cell cycle

During interphase, The DNA of the cell is called chromatin

Interphase

During interphase, cells go through three stages:

Interphase

1. Rapid growth and replication of the organelles. (G1 stage)

Interphase2. Replication of DNA . (S stage)

The cell replicates its strands of chromatin

Sister chromatids are the two identical strands of DNA that make up the duplicated chromosome.

They are held together by a structure called a centromere.

3. Growth and final preparation for cell division (G2 Stage

Interphase

Mitosis- The process of cell division that results in 2 identical cells(daughter cells) with the same number of chromosomes.

Only happens in body cells

Sub-stages of Mitosis: Prophase Metaphase Anaphase Telophase

Cytokinesis

Mitotic Phase

Duplicated DNA condenses into chromosomes

Prophase

Chromosomes line up in the middle of the cell

Metaphase

Sister chromatids in each duplicated chromosome separate and are pulled in opposite directions by the spindle fibers

Anaphase

Chromosomes begin to uncoil, and 2 new identical nuclei form

Telophase

Cytokinesis divides a cell’s cytoplasm forming a new cell membrane around each daughter cell.

In animal cells , a furrow in the middle of the cell gets deeper until the cell membrane comes together to divide the cell.

Cytokinesis

In plants, a cell plate grows outward toward a new cell wall until 2 new cells form

Cytokinesis

The cell cycle is important for :

for reproduction in some organisms

growth in multi-cellular organisms

replacement of worn-out or damaged cells

Repair of damaged tissues