Introduction to the Cell and Cell Division Sammi, Alex, Emily

Important History of the Cell 1655: A microscope was created by Robert Hooke

and saw the first cells

1683: Bacteria was discovered by Leewenhoek

1838: Cell theory was proposed by Schleiden and Schwann

1839: Cell theory applied to animals was published by Schwann

1869: DNA was isolated for the first time by Miescher

History of a Cell Continued..

1882: chromosomes were discovered when Walther Fleming used dyes to stain cells

1902: chromosomes were discovered to exist in pairs that are similar in structure by Walter Stanborough Sutton

1903: sperm and egg cells were discovered by Sutton to each have one pair of chromosomes

1941: genes control the production of enzymes by George W. Beadle

1944: DNA is the material responsible for heredity by Oswald Avery

History of a Cell Continued

Late 1980’s: DNA fingerprinting was used for the first time to solve a crime in Portland, Oregon

1997: the first adult animal was cloned; Dolly the sheep

2000: draft of DNA to clone humans

History of a Cell Images

http://www.youtube.com/watch?v=BI6Gbyxq8eY

(copy and paste)

Cell Theory

Cell Theory: all organisms are composed of cells.

-The Cell Theory is to biology as atomic theory is to physics

-Foundation of modern biology

Modern Tenants of Cell Theory

All living things are made up of cells

The structural and functional unit of all living things is the cell

Division of pre-existing cells makes new cells

Modern Cell Theory Continued

During cell division, hereditary information is passed from cell to cell

Most cells have the same chemical composition

Biochemistry and metabolism occurs in cells

Cell Differentiation

Cell Differentiation: growth of specific structures and functions in a cell to form a more complex cell

These specialized cells carry out specific tasks in the organism

For example, this happens in reproduction, when a zygote becomes a system of tissues

Cell Differentiation Video

http://www.youtube.com/watch?v=AvI8kwrYz_M

Cell Differentiation: Stem CellsStem Cell: after a cell divides, the cells now have

important genes that can produce any cell in the body

all cells in the body originated from stem cells

when you have an injury or illness, stem cells are used to replace cells and aid healing