Historical Development Cell Theory
1. Robert Hooke In 1662, he observed tiny compartments in the cork of a
mature tree and gave them the Latin name cellulae (meaning small rooms). This
was the origin of the biological term cell.
2. Anton Von Leeuwenhoek - By the late 1600s, he had observed diverse
protistans, sperm, even a bacterium an organism so small it would not be seen
again for another two centuries.
3. R.J.H. Dutrochet French botanist who prepared plant cells and studied them
between 1824 and 1830. He discovered and named the phenomenon of osmosis, which
is the passage of a liquid through a semi-permeable membrane. He was the first
to carefully study respiration and light sensitivity in plants.
4. Robert Brown In 1827, he noticed the constant presence of an opaque spot
in egg cells, pollen cells, and then cells of the growing tissues of orchid
plants and called this spot protozoa in 1834.
5. Dujardin He discovered one celled animals called rhizopoda, now called
protozoa in 1834.
6. Matthias Schlieden In 1838, he suggested that the nucleus and cell
development are closely related. He decided that each plant cell leads a double
life one independent, involving its development, the other as an integral
part of the plant.
7. Theodor Schwann In 1839, after years of studying the structure and growth
of animal tissues, he concluded that animals, as well as plants, consist of
cells and cell products, and even though the cells are part of a whole
organism, they have an individual life of their own.
8. Rudolf Virchow In 1849, he completed his studies of cell growth and
reproduction of their division into two cells. He concluded that every cell
comes from an already existing cell.
9. Walther Flemming In the early 1880s, while using dyes to study the
structure of cells, he found a structure, which strongly absorbed dye, and
named it chromatin. He observed that the chromatin separated into stringy
objects during cell division, which became known as chromosomes. Flemming named
the division of somatic cells mitosis, from a Greek word for thread. He also
observed that the chromosomes formed two star shaped structures on either side
of the dividing cell, which he named asters.
10. C. Golgi In 1898, he described the existence of a network of thread like
structures and small sacs (vesicles) in the cytoplasm of nerve cells. This
complex organelle composed of flattened sacs and vesicles is now known as a
Golgi body or Golgi apparatus.
11. J.D. Watson and F.H.C. Crick In 1953, after Watson realized that the
shape of the base pairs meant they could only be arranging in a certain way,
Watson and Crick published a paper proposing that the DNA moleule had double
helical structure.
State the three principles of the cell theory:
1. All organisms are composed of one or more cells.
2. The cell is a basic unit of life.
3. New cells arise only from cells that already exist.