Notes 3-1 Discovering Cells

Cells All living organisms made up of cells Cells are basic unit of structure and function in living things Cells are very small and are measured in micrometers (μm), one micrometer is one millionth of a meter! Remember one centimeter is only one hundredth of a meter! Look at your skin: one square cm contains over 100,000 cells!!

Cells and structure Your cells are the reason you are put together the way you are. They are why you have a body, a head, 2 arms, 2 legs, 10 fingers, 10 toes, etc… What in/on your body is made up of cells? (raise your hands) Your skin, muscles, bones, blood, organs, etc….

Cells and function Your cells are involved in all of the functions your body must perform Examples: White blood cells fight of infections Skins cells provide your body with protection Red blood cells help provide oxygen to your vital organs

Discovery of cells 1600s when microscopes came out Robert Hooke built a microscope and observed cork cells. Credited with naming them “cells,” meaning small rooms. Anton van Leeuwenhoek built a microscope and observed water samples. Found tiny moving organisms which he called “animalcules,” meaning little animals.

Cell Theory States: All living things are composed of cells. Cells are the basic units of structure and function in living things. All cells are produced from other cells.

Unicellular and Multicellular Unicellular, or single-celled, organisms include bacteria, the most numerous organisms on Earth. Multicellular organisms are composed of many cells. Unicellular Multicellular

Multicellular organisms Cells make up tissues, tissues make up organs, organs make up organ systems, organ systems make up organisms Example: A collection of nerve cells makes up nervous tissue, nervous tissue makes up most of the brain (organ), brain controls the nervous system (organ system) which is one of the major systems that make up you (the organism)

Cellular organization picture: Don’t Draw…. Just look and listen to teacher description…