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History of the Cell. How are these cells the same and how are they different?. What is a cell?. A cell is the basic unit of life . A cell is a structure within a living thing that has a boundary surrounding the material inside. How small is a cell?. How were cells discovered?.
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What is a cell? • A cell is the basic unit of life. • A cell is a structure within a living thing that has a boundary surrounding the material inside.
How were cells discovered? • Scientists were curious about what living things were made of. • So they created microscopes to take a closer look at living things.
Who were the main people involved in the discovery of cells? • Anton van Leeuwenhook • Robert Hooke • Robert Brown • Matthias Schleiden • Theodor Scwann • Rudolf Virchow
Anton von Leeuwenhoek • 1600s. • First to see and describe cells. • Used a simple microscope (one lens). • Looked at tiny living organisms in a drop of pond water (“wee beasties”).
Robert Hooke • 1665. • First to use the term, “cells.” • Used a compound microscope (2 lenses). • Looked at a slice of cork (dead cells). • Noted for seeing, describing, and explaining.
Robert Brown • 1831. • First to identify the nucleus. • Realized that nucleus was doing something important.
Matthias Schleiden • 1838. • First to conclude that all plants are made of cells.
Theodor Schwann • 1839. • First to conclude that all animals are made of cells.
Rudolf Virchow • 1855. • Cells reproduce: that is where new cells come from. • “When a cell exists, there must have been a pre-existing cell…”
What is the Cell Theory? • 1. All living things are made of cells. (Schleiden = plants, Schwann = animals) • 2. Cells are the basic units of structure and function in living things. • 3. New cells are produced from existing cells. (Virchow)
Word origins • eu….. means ‘true’ • pro…. Means ‘earlier than’ • karyon….. means ‘kernel’ • organelle…means ‘mini-organ’
Cells Come in a Variety of Shapes and Sizes • Most cells = 5 to 50 µm in diameter • Smallest= mycoplasma bacteria (0.2 µm in diameter) • Largest = Chaos chaos amoeba (1000 µm in diameter)