Cell Notes. Chapter 4

Historical Discoveries A) Hooke: A watchmaker who decided to try his skills at making a microscope. (Image at right on notes page.) Hooke was the first person to use the term “CELL” because what he was seeing looked like the rooms of a monastery, which were called cells at that time.

Historical discoveries (Continued) B) Leeuwenhoek: Improved Hooke’s microscope. He produced some scopes that were able to magnify images up to 500X. First to see: Protista, bacteria, spermatazoa. He presented Peter the Great with an “eel viewer” so that he could observe blood circulation in the eel.

Cell Theory:Schleiden, Schwann and Virchow 1) All cells come from pre-existing cells. 2) Cells are the smallest unit of living organisms. (Cells are the basic units of life) 3) All living organisms are made up of one or more cells.

Shape –vs- Function All cells have unique shapes which are not random, but instead serve specific functions. Altering the shape of a cell can alter its ability to function well. Ex: Why must blood cells take their shape? Why must neurons have their shape?

Why must blood cells take their shape? Neurons?

Endosymbiotic Theory The endosymbiotic Theory concerns the mitochondria, plastids, (Chloroplasts) and possibly other organelles of eukaryotic cells. According to this theory, certain organelles originated as free-living bacteria that were taken inside another cells as endosymbionts. Mitochondria developed from proteobacteria and chloroplasts from cyanobacteria.

Endosymbiosis

Prokaryotes vs Eukaryotes

Prokaryotes Single cells only Limited parts (ribosome, cell membrane, cell wall) No specific compartments to perform key metabolic functions Oldest cells on the earth Example: Bacteria

Eukaryotes Single AND multicellular Multiple organelles Organelles serve as compartments for specific metabolic functions Younger cells Ex: Plant and animal cells, protista

FYI Kingdom Protista