Cell Division

By: Mr. Kauffman

Outline• Cells Review• What is cell

division?• The Cell Cycle• Interphase• Mitosis• 4 Steps of Mitosis• Results of Mitosis

• Meiosis• 8 Steps of Meiosis• Results of Meiosis• 2 Types of Cell

Division

Cells Review• Cell: smallest part of any

living thing that carries out the functions necessary to support life

• Unicellular organism: living thing made up of 1 cell

• Multicellular organism: living thing made up of many cells

What is cell division?• Cell division: a way to

produce more cells– Usually 1 cell divides to make 2

cells

• Why is cell division important to multicellular organisms?– Its how they grow– Replace cells that have died

• Why is cell division important to unicellular organisms?– Its how they reproduce

Cancer cell dividing

E. Coli cell dividing

The Cell Cycle• Cell cycle: everything

that happens from 1 cell division to the next– 2 parts

1. Interphase

2. Mitosis

Interphase• Interphase: longest

part of the cell cycle– The cell prepares to

divide• It grows in size• It copies its DNA

Mitosis• Mitosis: Part of the cell

cycle• Mitosis has 4 steps:

1) Prophase

2) Metaphase

3) Anaphase

4) Telophase

Cell Division

Mitosis Vocabulary

• Diploid = A cell whose chromosomes that appear in pairs.

• Haploid = A cell that has only one of each type of chromosome.

• Parent Cell = In cell reproduction name for the original cell.

• Daughter Cell = In cell reproduction the name for the cells produced.

4 Steps of Mitosis

1. Prophase– 1st step– Chromosomes

form in nucleus (look like X’s)• These are how

the DNA is stored in our cells

• Humans have 46 single chromosomes (23 pairs)

– Centrioles and spindle fibers begin to form

4 Steps of Mitosis

2. Metaphase– 2nd step– Spindle fibers

attach to the chromosomes

– Chromosomes are lined up in the middle of the cell

4 Steps of Mitosis

3. Anaphase– 3rd step– Chromosomes

are pulled apart– ½ of each

chromosome goes to each end of the cell

4 Steps of Mitosis

4. Telophase– 4th step– Cytoplasm

begins to pinch in at center of cell

– Eventually the 1 cell splits to form 2 cells

– Chromosomes unravel

Results of Mitosis

• Produces normal, diploid cells in the human body– Ex: skin and muscle

• 1 cell splits to form 2 cells– The new cells are identical

to each other– The new cells are also

identical to the original cell

Meiosis• Meiosis is cell division

that produces reproductive cells– Ex: sperm and egg cells

• Has 2 cell divisions– Basically goes through

mitosis 2 times

• Produces 4 cells– The 4 new cells have ½

the amount of DNA than the original cell had

2 Types of Cell Division in Humans

½ the DNAComparison to original cell

Identical

23 (single)# of chromosomes in cells

46 (single)

4# of cells produced2

PMAT (1 and 2)Step namesPMAT

8# of steps4

Reproductive cellsTypes of cells produced

Normal body cells

MeiosisCharacteristicsMitosis