Tuesday, September 20
Bell Work:
What are the 3 parts of the cell theory?
The microscope aided in the discovery of cells because the majority of cells are too small to be seen with the naked eye.
Dutch eyeglass maker Zacharias Janssen is credited with the inventor the microscope.
In biology we use a compound microscope which means in contains more than one lens.
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Robert Hooke used a three­lens compound microscope in 1665 to examine a thin slice of cork. (Cork is the outer bark of an oak tree) and the named what he saw CELLS.
Anton van Leeuwenhoek was the first to describe living cells when he observed single celled organisms swimming in pond water.
As people continued to improve the microscope, by making it easier to use, more sturdy and having greater magnification more organisms were discovered.
This development led to many questions such as:
Is all living matter composed of cells? Where do cells come from?
Matthias Schleiden (1838) proposed that all plants are composed of cells.
Theodor Schwann (1839) first proposed that living animals are composed of cells and then that all living organisms are composed of cells.
Rudolf Virchow (1855) proposed that all living cells come from preexisting cells.
The major principals of the cell theory:
1. All organisms are made of cells.
2. All existing cells are produced by other living cells.
3. The cell is the most basic unit of life.
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Your body contains trillions of cells and they come in many different shapes, sizes and functions. However, they all have 3 characteristics in common.
1. They have a membrane that encloses them and controls movement in and out of the cell.
2. They contain DNA.
3. They all have cytoplasm.
Cytoplasm is a jellylike substance that contains dissolved molecular building blocks like proteins, minerals and ions. Organelles are structures specialized to perform specific functions in a cell. They are related because if an a cell contains organelles they will be found in the cytoplasm.
Eukaryotic and Prokaryotic
Prokaryotic
Eukaryotic
Has a nucleus
Has organelles
Nucleus contains the DNA
Multicellular or unicellular
Do not have a nucleus
No organelles
Only single­celled organisms
DNA
Cell Membrane
Cytoplasm
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Need to find the following information:
1. Function­ What does it do?
2. Structure­ What does it look like?
3. Where it is located in cell?
4. What type(s) of cells is it found in?
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