unit one notes
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Unit One Notes. Cells – theory. THE FIRST OBSERVED CELLS. Robert Hooke (1665) – a British scientist who used a homemade microscope Hooke looked at a piece of cork from the bark of an oak tree - PowerPoint PPT PresentationTRANSCRIPT
CELLS – THEORY
Unit One Notes
THE FIRST OBSERVED CELLS Robert Hooke (1665) – a British
scientist who used a homemade microscope
Hooke looked at a piece of cork from the bark of an oak tree
It looked like the small rooms monks lived in at that time, so he named them Cellulae, which means “little room” in Latin
He could not see animal cells because they did not have a cell wall
Interesting fact – all known portraits of Hooke were destroyed in part because of an ongoing fued with Isaac Newton
SEEING CELLS IN OTHER LIFE FORMS
LEEUWENHOEK – IN 1673, THIS DUTCH MERCHANT WHO WAS INSPIRED BY HOOKE LOOKED AT POND SCUM UNDER THE MICROSCOPE. HE ALSO LOOKED AT GOOP SCRAPED OFF OF TEETH.
HE WAS THE 1ST PERSON TO SEE BACTERIA (CALLED THEM WEE BEASTIES), AND REALIZE THAT ANIMAL CELLS WERE DIFFERENT FROM PLANT CELLS
Cell Theory
A fundamental idea of modern biology:
The three principles of the cell theory state:1. All living organisms are
composed of one or more cells2. Cells are the basic unit of
structure and organization of all living organisms (basic unit of life)
3. Cells arise only from existing cells, with cells passing copies of their genetic material on to their daughter cells. (cells make more cells)
Two Types of Cells
Cells come in different shapes and sizes based on the function they perform.
Cells have been grouped into 2 broad categories based on their internal structures:
Prokaryotic Eukaryotic (these are
generally 1-100x larger)
Prokaryotic Eukaryotic
Cells without a nucleus
Example: Bacteria
Cells with a nucleus and other membrane bound structures. (Plant and animal cells)
Two Major Types of Cells
Plant Cells Animal Cells
Have Cell WallsA Large VacuoleChloroplasts
Have a Cell Membrane
Small VacuolesNo Chloroplasts
Eukaryotic Cells
Eukaryotic Cells cont. Eukaryotic cells are larger and
more complex Have specialized internal
structures – called organelles (like a nucleus)
Most multicellular organisms are eukaryotes (although some unicellular organisms like yeast are eukaryotes)
Eukaryotic cells have specialized functions (you have over 200 types of cells)
Believed to have evolved from prokaryotes; has led to cell diversity that helps organisms better adapt to their environments.
Inner Life of a Cell
The Inner Life of the Cell (full version).mp4 [www.keepvid.com].3gp