1. History of Cell Discovery

2. Microscope view of cells ► Robert Hooke – first to see cells! (1663) ► Named them “cells” because they look like monk quarters. ► Latin term 'cellula' means small compartment. ► Only observed cell walls because cork cells are dead. Cells with stone beds

3. Microscope view of cells Anton Van Leeuwenhoek – first to observe living cells (1675).  Bacteria, protozoa, and blood cells  Called them "animalicules" ► Made over 500 microscopes, of which only 10 survive today. (single lens) monocular microscopes 200X

4. Scientists of Cell Theory ► Mattias Schleiden – botanist who observed that the tissues of plants had cells (1838) ► 1838, Schwann and Schleiden were enjoying coffee and talking about their studies on cells. coffee and talking about their studies on cells. When Schwann heard Schleiden describe When Schwann heard Schleiden describe plant cells he was struck by the similarity of plant cells he was struck by the similarity of these plant cells to animal cells he had observed. these plant cells to animal cells he had observed. The two scientists went immediately to Schwann's lab to The two scientists went immediately to Schwann's lab to look at his slides. look at his slides.

5. Scientists of Cell Theory ► Theodore Schwann – zoologist who observed that the tissues of animals had cells (1839). ► ► He coined the term metabolism. ► ► He formulated the basic principles of embryology.   the egg is a single cell that eventually develops into a complete organism. ► ► He also isolated a substance responsible for digestion in the stomach, the first enzyme and named it pepsin.

6. Scientists of Cell Theory ► Rudolf Virchow – reported the correct interpretation of cell formation. ► "Omnis cellula e cellula"... “  All cells only arise from pre-existing cells".

7. Cell Theory 1. All known living things are composed (made of) of one or more cells. 2. The cell is the smallest unit of life. 3. All cells come from pre-existing cells. 4. All cells carry on similar functions, such as extracting energy from food to sustain life. 5. All cells contain hereditary information.

8. Terms ► Cell – the smallest unit that can carry on the processes of life. ► Unicellular – consists of only one cell ► Multicellular – consists of more than one cell

9. Basic cell Structures ► ► Cell Membrane – outer boundary ► ► Nucleus – control center ► ► Cytoplasm – stuff between membrane & nucleus

10. Two Basic Cell Types ► Prokaryotic – lacks internal organelles.  Has a cell membrane & a cell wall  Has NO nucleus. ► Means “before the nucleus”  Usually Unicellular organisms  Ex: Bacteria

11. Two Basic Cell Types ► Eukaryotic – contains organelles.  Has a nucleus  Has a cell membrane  Usually multicellular organisms  Ex: Plants, animals, and protists