The cell theory was developed in the 19th century based on observations by early microscopists. Robert Hooke first observed dead plant cells in the 1600s and coined the term "cell". Anton van Leeuwenhoek later observed the first living cells using an early microscope. In the 1830s, Matthias Schleiden concluded that plants are made of cells. Theodor Schwann then concluded that animals are also made of cells. Together these conclusions formed the first two tenets of cell theory - that all organisms are made of one or more cells, and that the cell is the basic unit of life. Rudolf Virchow later added the third tenet - that all cells come from pre-existing cells.

1. CELLTHEORY
BY-MOHIT HINSU

2. HISTORY OF CELL
■ The first cells from an organism (cork)[dead plant cell] were
observed by Hooke in the 1600s.
■ He saw a series of walled boxes that reminded him of the tiny
rooms, or cellula, occupied by monks.
■ When looking at under the microscope he described it as like the
tiny room that monkes lived in called cellula.
■ And then they give name cell

3. Antony van leeuwenhoek
■ Anton van Leeuwenhoek is another scientist who saw these cells soon
after Hooke did.
■ He made use of a microscope containing improved lenses that could
magnify objects almost 300-fold, or 270x.
■ They see first living cell.
■ Leeuwenhoek named these “animalcules,” which included protozoa
and other unicellular organisms, like bacteria.
■ He also made over 500 microscopes to view specific objects.

4. ■ Leeuwenhoek made his own microscope lenses, and he was so
good at it that his microscope was more powerful than other
microscopes of his day. In fact, Leeuwenhoek’s microscope was
almost as strong as modern light microscopes. Using his
microscope, Leeuwenhoek was the first person to observe human
cells and bacteria.
■ FATHER OF MICROBIOLOGY ANTONY VAN LEEUWENHOEK.

5. CELLTHEORY
■ Credit for developing cell theory is usually given to two scientists:
Theodor Schwann and Matthias Jakob Schleiden
■ While Rudolf Virchow contributed to the theory, he is not as
credited for his attributions toward it.
■1838-Matthias Jakob Schleiden ,BOTANIST FROM
GERMANY.
■ Every structural part of a plant was made up of cells or the result
of cells.

6. ■ Theodor Schwann [ physician ][1839]
■ Schwann published his observations in 1838 in the Neue notisen
geb. nat.-heilk. This was followed in 1839 by the publication of his
book Mikroskopische Untersuchungen über die
Uebereinstimmung in der Struktur und dem Wachsthum der
Thiere und Pflanzen (Microscopic investigations on the similarity
of structure and growth of animals and plants). It is considered a
landmark work, foundational to modern biology.
■ states that along with plants, animals are composed of cells or the
product of cells in their structures.This was a major advancement
in the field of biology since little was known about animal structure
up to this point compared to plants.

7. ■ From these conclusions about plants and animals, two of
the three tenets of cell theory were postulated.
■ 1. All living organisms are composed of one or more cells.
■ 2. The cell is the most basic unit[structural and functional] of life.
 Rudolf Virchow [1855]added the third tenet to
cell theory.
 3. All cells arise only from pre-existing cells.

8. Modern interpretation
■ The generally accepted parts of modern cell theory include:
■ All known living things are made up of one or more cells
■ All living cells arise from pre-existing cells by division.
■ The cell is the fundamental unit of structure and function in all
living organisms.
■ The activity of an organism depends on the total activity of
independent cells.[citation needed]
■ Energy flow (metabolism and biochemistry) occurs within cells.
■ Cells contain DNA which is found specifically in the chromosome
and RNA found in the cell nucleus and cytoplasm.
■ All cells are basically the same in chemical composition in
organisms of similar species

9. What are the exceptions to cell theory?
■ Viruses are not applicable to cell theory. They are made up of
proteins and one of nucleic acids i.e., DNA or RNA. So they lack
protoplasm, the essential part of the cell.