The Cell
Definition of Cell note: only write down text in red A cell is the smallest unit that is capable of performing life functions.
Cell Theory All living things are made of cells. Cells are the smallest living units. All cells come from preexisting cells through cell division.
Who came up with this theory? 1.Robert Hooke(1665) First person to see cells, he was looking At cork and noted that he saw many boxes That look like prison cells Let’s call these things cells!
Who came up with this theory? 2. Schleiden (1838) All plants are made of cells! Onion skin cells
3. Schwann Who came up with this theory? All animals are made of cells! Human red blood cells
Who came up with this theory? 4. Virchow All cells come from pre-existing cells!
Examples of Cells Amoeba Proteus Plant Stem Red Blood Cell Nerve Cell Bacteria
How big are cells? Mostly Microscopic Measured in microns (µm) A µm is one millionth of a meter!
How big are cells? Bacteria (aka E.coli) Size=1 µm by 3 µm
How big are cells? Human red blood cell = 8 µm
How big are cells? Largest cell on the human body is the ovum 1000 µm in diameter (1 mm)
Two Types of Cells Prokaryotic Eukaryotic
Prokaryotic Do not have organelles surrounded by membranes Few internal structures Example: Bacteria
Eukaryotic Contain organelles surrounded by membranes Most living organisms are eukaryotes PlantAnimal
“Typical” Animal Cell
“Typical” Plant Cell