Aristotle (384 BC - 322 BC)
a Greek philosopher whose theory of abiogenesis or spontaneous generation was accepted for over 2000 years.
created his theories on the origin of life based on his many observations, however, he did not conduct any scientific experiments to test his ideas.
Francesco Redi (1626 - 1697)
Italian physician who used controlled scientific experiments to refute the theory of spontaneous generation
Louis Pasteur (1822 - 1895)
French scientist who finally settled the continued debate of the theory of abiogenesis.
Robert Hooke (1635 - 1703)
looked at cork with a compound light microscope (30X magnification) and was the first to see and name "cells".
Antony van Leeuwenhoek (1632 - 1723)
Dutch linen merchant who first described single-celled microorganisms. He called his sightings "animalcules"
Matthias Schleiden (1804 - 1881) and Theodor Schwann (1810 - 1882)
German scientists who studied cells in hundreds of plants and whose research contributed to the cell theory, stating that "all organisms are made of cells "
German physician who made microscopic observations of cells dividing and completed the cell theory still accepted today.
The Cell Theory
1. All organisms are composed of one or more cells.
2. The cell is the smallest functional unit of life.
3. All cells are produced from other cells.
specimens are illuminated with a beam of electrons instead of a beam of light. It magnifies up to 1.2 million times
sections of DNA that direct the activities of our cells
- changes in the gene can cause improper cell function
eg. Sickle cell anemia
carries all genetic information of the organism, coiled to form chromosomes, found in the nucleus of every cell
non-cellular structure made of a piece of genetic material enclosed in a protein coat.
In order to reproduce, a virus must infect a cell