Is the process by which cells divide into 2 daughter cells Cells do this to prevent from becoming to large Recall…why don’t cells grow to be large?

If a cell didn’t prepare before it divided, would it be able to survive? NO Before a cell can divide it MUST: 1. Make a copy of the DNA, this way each cell can have a complete set 2. Have extra of most organelles so that each of the daughter cells will be functional

Usually is stored in the form of chromatin Chromatin carries all of an organisms genetic information Are unwound, non-visible strands of DNA Condenses to chromosomes/ chromatids before the cell divides Chromatids and chromosomes are tightly wound up DNA that is visible

Before a cell divides, each chromosome is copied and when they condense into chromatids, there are 2 identical copies These are called Sister Chromatids The sister chromatids are connected together by a centromere

Is a series of events that a cell undergoes as it grows and divides The four main steps are 1. Growing 2. Preparing for Dividing 3. Dividing into 2 daughter cells 4. Starting at step 1 again

The 2 major phases of the cell cycle are 1. Interphase—this is the period of growth that a cell undergoes, the time when it is NOT dividing It also prepares to divide during this time by making a copy of the DNA 2. Mitosis—this is the time when a cell is actively dividing It consists of 4 steps, plus cytokinesis

The nuclear envelope breaks down Chromatin condenses into the chromosomes. Centrioles separate to opposite ends of the cell. Mitotic spindle begins to form.

Chromosomes line up at the equator to the cell The spindle fibers connect to the centromeres of each sister chromatid

Centromeres joining the sister chromatids together split apart The chromatids are pulled to opposite sides of the cell

Chromosomes begin to decondense The nuclear envelope reforms (this time there is 2, one on each side) The spindle breaks apart

Means to divide the cell, so it is after mitosis and the cell splits into 2 independent cells In animals, the cells suck in and then “pinch off” In plants, a cell plate is formed that gradually turns into a new cell wall

Are a class of hormones that control the cells cycle They decide when cells are to divide and when the are NOT to divide Cancer is considered UNCONTROLLED cell division and can lead to serious problems