CELL THEORY | EMERGENCE OF CELL THEORY (Simple & Easy Note)

CELL THEORY | EMERGENCE OF CELL THEORY (Simple & Easy Note)

By learningcentury.blogspot.com

EMERGENCE OF CELL THEORY

Following are the scientists contributed to the emergence of cell theory.

1)    Robert Hook (1665)

2)    Anton Van Leeuwenhoek

3)    Jean Baptist-de-Lamarck  (1809)

4)     Robert Brown (1831)

5)     Mathias Schleiden (1838)

6)     Theodor Schwann (1839)

7)     Jan Evangelista Purkinje(1839)

8)     Rudolf Virchow (1855)

9)     Louis Pasteur (1962)

1)   Robert Hook (1665)

a.    In 1665, Robert Hooke, an English scientist, was the first person to observe cells with a small microscope.

b.    He magnifies thin slices of cork 30 times (30x) and able to see individual cork cells.

2)   Anton Van Leeuwenhoek

a.    He was a Dutch Scientist and at the same time made a much more powerful microscope.

b.    He magnified firstly “animalcules” pond water with 300 times (300x) and observe unicellular organisms.

3)   Jean Baptist-de-Lamarck  (1809)

a.    He also observe cells from the parts of plants and animals under microscope.

b.    He concluded that all living organisms are made up of cellular tissues.

4)    Robert Brown (1831)

a.     He discovered the nucleus spherical body in plant cells.

b.     He made a new concept about cell that cells are not empty chambers.

5)    Mathias Schleiden (1838)

a.     In 1838, a German botanist Mathias Schleiden claimed that all plants were made of cells.

6)    Theodor Schwann (1839)

a.     He was German Zoologist, supported Schleiden and proved that animals were also made up of cells.

7)    Jan Evangelista Purkinje(1839)

a.     In 1839, a Czech Scientist Jan Evangelista Purkinje gave the name “protoplasm” to the fluid substance of the cell.

8)    Rudolf Virchow (1855)

a.     In 1855, German scientist Rudolf Virchow changes the ideas of many scientists.

b.     By giving a statement  “Omnis cellula e cellula ” means that new cells arise from pre-existing cells by cell division,

9)    Louis Pasteur (1962)

a.     Louis Pasteur in 1962 proofs experimentally the Virchow’s idea that microorganisms (bacteria) arise from existing bacteria.

CELL THEORY

MAIN POINTS:

After the first observation of the life under the microscope, it took two centuries of research to formulate the cell theory.

Schwann and Schleiden summarized the cell theory into three conclusions I-e

1)     All animals and plants are made up of cells and cell products. Some are unicellular and some are multicellular.

2)     Cell is the structural and functional units of living organisms.

3)     New cells arise from the pre-existing cells by cell division,

The expanded version of the cell theory also includes;

Ø  Cells carry genetic material passed to daughter cells during cell division.

Ø  All cells are essentially the same in chemical composition.

Ø  Energy flow occurs within cells

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