11+Cell+Theory

=//Cell Theory//=

2.1.1 Outline the Cell Theory
2. The cell is the smallest form or unit of life. 3. All cells come from pre-existing cells.**
 * 1. All living things are made up of cells.

2.1.2 Discuss the evidence for the cell theory
1600s--Anton van Leeuwenhoek looks at a drop of pond water under a primitive microscope and observes microscopic and single celled organisms. 1665--Robert Hooke discovers cells by looking at a piece of cork (made from tree bark) under a primitive microscope. He noticed the cell walls of the dead plant tissue. 1839--Theodor Schwann notes that the cells of animals and plants are very alike in structure. This evidence supports the first tenet of cell theory, that all organic matter is made up of cells.
 * Like any theory, cell theory is only based on previous observations and facts. It is an accepted theory because it is supported by evidence gathered by many (although it would be imposssible to observe every known living and non living thing). A few scientists involved in the establishment of cell theory, and their discoveries:

1839--Matthias Schleiden observes that a plant embryo would grow from a single cell, and that all the tissues of the plant are made of cells. 1855--Rudolph Virchow observes that unusual events in the body occured when there was irregular cellular activity. This evidence support the tenet of cell theory that all cells come from pre-existing cells (by division).**

2.1.3 State how unicellular orgaisms carry out all the functions of life
All living things: reproduce, utilize a form of metabolism (take in/use energy), homeostasis, excretion, growth.**
 * Unicellular organisms can carry out all the functions that multi cellular beings such as humans carry out.