Cells (note, these are notes for Ch. 4 in Modern Biology text)

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cells= the basic units of living organisms

Van Leeuwenhoek= used the simple light microscope (one lens, used natural light)

compound light microscope (200 years later)= uses a series of lenses to magnify objects in steps, magnifies up to 1500 times. (what we use today)

Robert Hooke= designed the early compound microscope (1655); looked at cork; he saw little shapes which looked like cells in a jail (monastery), he called them "cells".

Matthias Schleiden= all plants are composed of cells (1830)

Theodore Schwann= all animals are composed of cells

The Cell Theory:

1. all organisms are composed of one or more cell

2. the cell is the basic unit of organization of organisms

3. all cells come from pre-existing cells

electron microscope= uses a beam of electrons rather than light; can magnify 500,000 times. used to see structures inside of a cell

Two Types of Cells:

1. prokaryotes: cells that lack internal membrane-bound structures

2. eukaryotes: cells that have internal membrane-bound structures; most plant and animal cells

organelles= membrane-bound structures within a cell; "little organs"

nucleus= central organelle; manages cellular functions