Cell Division By Mr Kauffman Outline Cells Review

Cell Division By: Mr. Kauffman

Outline • • • Cells Review What is cell division? Why is cell division important? The cell cycle 4 Steps of mitosis Results of mitosis

Cells Review • Cell: smallest part of any living 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 – 1 cell divides to make 2 cells • Why is cell division important to multicellular organisms? Cancer cell dividing – Its how they grow – Replace cells that have died • Why is cell division important to unicellular organisms? – Its how they reproduce E. Coli cell dividing

The Cell Cycle • Cell cycle: the events that take place in between cell divisions • Interphase: longest part of the cell cycle – When the cell grows and prepares to divide – The cell copies its hereditary material (DNA) • Each new cell will receive a copy of the hereditary material

Mitosis • Mitosis: part of the cell cycle when the cell divides to form 2 identical cells – Occurs after interphase – The 2 new cells are identical to each other and identical to the original cell • Mitosis has 4 steps: 1) Prophase 2) Metaphase 3) Anaphase 4) Telophase Cell Division

4 Steps of Mitosis 1. Prophase – 1 st step – Chromosomes form in nucleus (look like X’s) • These are how the DNA is stored in our cells – Centrioles and spindle fibers begin to form

4 Steps of Mitosis 2. Metaphase – 2 nd step – Spindle fibers attach to the chromosomes – Chromosomes are lined up in the middle of the cell

4 Steps of Mitosis 3. Anaphase – 3 rd step – Chromosomes are pulled apart – ½ of each chromosome goes to each end of the cell

4 Steps of Mitosis 4. Telophase – 4 th 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 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 • Parent cell: name for the original cell • Daughter cell: name for the cells produced

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 Mitosis Normal Body Cells Characteristics Types of Cells Produced 2 Final # of Cells Produced Identical Comparison to Original Cell Meiosis Reproductive Cells (sperm end egg) 4 ½ as much DNA # of Steps 4 8