1. CELL DIVISION
As cells grow they must divide
Why?…(write your own answer)
DNA and cell division
Both daughter cells need a complete set of DNA, nothing missing, nothing extra
DNA starts out as Chromatin (spread out DNA molecules)
Chromatin turns into Chromosomes by the process of Condensation (tightly folding)

2. Chromosomes
Chromosomes are the structures that contain genetic material we are passing from generation to generation in our cells.
Chromatin is the relaxed form of DNA in a cell’s nucleus.
Chromosomes are much more organized than chromatin.

3. Wound up in a big mess=Chromatin!
nucleus
DNA
Very, very long!
Wound up in a big mess=Chromatin!
A very small piece of a chromosome=a GENE!
Very Organized = Chromosomes

4. How do we get chromosomes from our DNA?

5. CELL DIVISION
A Chromosome
1 chromatid Centromere
2 Identical copies

6. CELL CYCLE Open book to pg 246 Cell cycle is in 5 phases
G1 ; S ; G2 ; M ; C
G1 - Most of cell’s growth and activity
S - DNA replicates
G2 - Final preparations for division
M - Nuclear division (mitosis) - Divided into 4 stages
C - Cytokinesis - division of the cell

7. INTERPHASE
In between cell divisions (G1 , S, and G2 phases)
Most of the cell’s life is in interphase
Chromosomes are in the form of chromatin (diffuse and invisible)
Each DNA replicates (makes a copy of itself)
Centrioles begin to move to poles of cell

9. PROPHASE First stage of actual mitosis
Chromatin condenses into chromosomes
Nuclear membrane disappears
Asters form at poles of cell (Not visible in plants)
Astral rays connect to centromeres on chromosomes
Asters and Astral rays together called the spindle
Astral rays
Chromosomes
Aster

10. METAPHASE Chromosomes are pulled by astral rays
Chromosomes line up along the equator of the cell

11. ANAPHASE Centromeres break
Each chromosome is pulled apart into separate chromatids
Spindle pulls chromatids toward poles

12. TELOPHASE Chromosomes disappear Nuclear membranes reappear
Spindle disappears
Cytokinesis -Cell membrane divides cell into 2 daughter cells
(In plants cell wall forms between daughter cells)
Daughter cells go back to interphase

19. Mitosis: animal cell

38. Mitosis: plant cell

56. The Internet is full of great Mitosis study tools….