The Cell Theory
WHAT IS A CELL?
n The cell is the _______________________________.
n It is the _________________ structural and functional unit of an organism.
n The average human being is composed of around __________________ individual cells!!!
n It would take as many as _____________ to cover the area of a dot on the letter “i”
Levels of Organization: Cell à ____________ à ____________ à Organ System à ____________
DISCOVERY OF CELLS:
1665- English Scientist, ___________________, discovered cells while looking at a thin slice of ________.
n He described the cells as ________________________ or a honeycomb
n He thought that cells only existed in plants and fungi
1673- Anton van Leuwenhoek discovered ____________________ organisms in __________________
n He called them “_________________”
n He also observed blood cells from fish, birds, frogs, dogs, and humans
n Therefore, it was known that cells are found in ______________ as well as ________________
A Big Time Gap (150-200 years!)
n Between the Hooke/Leuwenhoek discoveries and the mid 19th century, very little cell advancements were made.
n This is probably due to the widely accepted, traditional belief in _______________________.
n Examples:
-____________ from dirty clothes/corn husks
-_______________ from rotting meat
Later, much doubt existed around Spontaneous Generation
n Conclusively disproved by Louis _______________ à
1838- German Botanist, Matthias Schleiden, concluded that ____________________________________
1839- German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all ____________________________________________.
1858- Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must arise from preexisting cells.
THE CELL THEORY
1. All organisms are composed of ____________________________.
2. The cell is the _____________________________ in all living things.
3. All cells are ________________________________of preexisting cells.
WHAT WE KNOW ABOUT CELLS NOW:
n All cells contain __________________ information (DNA).
n Chemical and physiological processes happen _________________ the cell (movement, digestion).
n There are structures (___________________) within the cell that perform important jobs.
HOW HAS THE CELL THEORY BEEN USED?
The basic discovered truths about cells, listed in the Cell Theory, are the basis for things such as:
n Disease/Health/Medical Research and Cures (AIDS, Cancer, Vaccines, Cloning, Stem Cell Research, etc.)