1. The Cell Cycle:
Mitosis Notes

2. Facts Somatic cells – “soma” means body
Body cells each contain the same number of chromosomes
How many chromosomes do human body cells have? 46

3. Chromosome = cell structure that contains the genetic material in the form of DNA. This is located inside the nucleus.
Centromere
Chromatid
Sister Chromatid

4. Centromere = cell structure that joins two chromatids together to form a sister chromatid.
Chromatid = one copy of the original chromosome.
Sister chromatid = identical halves of the duplicated parent (original) chromosome formed during interphase.

5. Interphase
The time between the formation of the cell and the next mitosis
Duplication of genetic material
Produces organelles
Assembles structures needed for mitosis

6. Phases of Mitosis
Prophase – this is the first step of mitosis and it lasts the longest. Usually 60% of the total time for mitosis.
Chromosomes coil up into short rods
Nucleolus and nuclear membrane disappear
Spindle fibers form between centrioles
Centrioles move to opposite ends of the cell

7. Metaphase – second phase of mitosis
Meta = middle
Centromeres of chromosomes attach to spindle fibers
Chromosomes are arranged along the center line of the cell

8. Anaphase – third phase of mitosis
Centromeres separate
Chromatids separate and become separate chromosomes again
Spindle fibers pull chromosomes apart to opposite ends of the cell
Plasma membrane begins to pinch in the middle

9. Telophase – final stage of mitosis
Nuclear membrane forms around each set of chromosomes
Nucleolus and plasma membrane re-form

10. Cytokinesis – the division of cytoplasm
Animal cells – plasma membrane pinches in at the end of telophase and two new cells separate. Plant cells – since plant cells have a rigid cell wall, the plasma membrane can’t just pinch in. So, a cell plate forms across the middle of the cell to separate the two cells into separate cells.