“…For every living organism is, or at some time has been, a cell.” E.B. Wilson, 1925

Why Study Cell Biology?

Cells are Us

A person contains about 100 trillion cells. That’s 100,000,000,000,000 or 1 x 1014 cells.

There are about 1,000 different cell types in humans

Cells are tiny, measuring on average about 0.002 cm (20 um) across. That’s about 1250 cells per inch.

nerve cell

Red and white blood cells

How big are cells?• Bacteria e.g. Eschericia coli (aka E.coli)

• Size=1 µm by 3 µm (one millionth of meter!)

• Human red blood cell = 8 µm

Largest cell = yolk of an ostrich egg

The Cell Theory (1838-1839)**

All organisms are composed of one or more cells.

Cells are the smallest living things.

Cells arise only by division of previously existing cells.

Schleiden

Schwann

http://www.youtube.com/watch?v=gEwzDydciWc&feature=related

All cells today came from an original cell….

Bacteria on the Head of a Pin

Animal Cell

The Nucleus Think of the nucleus as the cell’s control center.

Two meters of human DNA fits into a nucleus that’s 0.000005 meters across.

The Lysosome

•Recycling cellular parts

Functions:

•Digesting food or cellular invaders

The Mitochondrion

Energy!!

Mitochondria and Health

Plant Structures

The Chloroplast

The Solar Panel of the Plant Cell!

Two Other Unique Features of Plant Cells

The central vacuole may occupy 90% of a plant cell.

Cell Walls = Great Strength

Cytoplasm

A white blood cell using the cytoplasm to grab a bacterium.

The Cytoplasm in Action

How do cells move?**

• Flagella

• Cilia

• False feet

• http://www.youtube.com/watch?v=KxTYyNEbVU4&feature=related

http://www.youtube.com/watch?v=7pR7TNzJ_pA&feature=related

http://www.youtube.com/watch?v=_k78AWnDaqA

Cell movement

Two Different Types of Cells**

A eukaryotic cellProkaryotic cell

Us vs. Them -Eukaryotes and Prokaryotes

Prokaryotes

Eukaryotes

Amoeba Zombie Cells