Transcript Cell Theory
The Discovery of Cells What does this look like to you? Robert Hooke • 1665 Used a microscope to look at cork (a plant tissue) • He thought cork looked like little boxes • Named the boxes “cells” which means little rooms in Latin What Hooke’s microscope looked like More about Hooke • Scarred from childhood smallpox • First to examine fossils with a microscope • Used a telescope to describe Jupiter’s Great Red Spot and rotation of Mars What else did Hooke see? • Looked at plants, fungi, fish scales, feathers and eyes of flies • Thought cells only found in plants Anton von Leeuwenhoek • Saw first live cells • He named creatures he saw in pond scum “animalcules” Anton von Leeuwenhoek • Looked at blood cells from different animals • Looked a tartar from teeth • First to see bacteria • Discovered yeasts are living organisms Matthias Schleiden • Studied lots of plant tissues – all of which contained cells • Concluded all plants are made of cells Theodore Schwann • Studied lots of animal tissues –all of which contained cells • Concluded all animals are made of cells Theodore Schwann • Wrote the first two parts of the cell theory –1. All living organisms are composed of one or more cells –2. The cell is the basic unit of life in all living things Rudolf Virchow • A pathologist • All cells come from pre-existing cells Cell Theory • 1. All living organisms are composed of one or more cells • 2. The cell is the basic unit of life in all living things • 3. All cells come from existing cells Things cells have in common • Cell membrane: acts as a barrier between inside of cell and cell’s environment • Hereditary material: DNA • Small Size Things cells have in common • Cytoplasm: fluid inside the cell • Organelles: structures inside the cell –Only some cells have membrane bound organelles Two types of cells • Prokaryotic • Eukaryotic Two types of cells • Prokaryotic –DNA not in a membrane bound nucleus –Cell membrane –Cytoplasm • Eukaryotic –DNA in a membrane bound nucleus –Cell membrane –Cytoplasm Two types of cells • Prokaryotic • Eukaryotic –Some have cell –Cell Wall walls –No membrane –Contains bound membrane bound organelles organelles –Have –Have ribosomes ribosomes –Can be unicellular or multicellular –Unicellular Two types of cells • Prokaryotic –Very small –Reproduce by binary fission –Circular DNA –Bacteria: • Staphlococcus aureus • Eukaryotic –About 10 times larger than bacteria –Reproduce by mitosis –Linear DNA –All other cells Two types of cells • Prokaryotic • Eukaryotic