A lesson about different theory of cell

1. CELL THEORY

2. Scientists once thought that life
spontaneously arose from
nonliving things. Thanks to
experimentation and the invention
of the microscope, it is now known
that life comes from preexisting life
and that cells come from
preexisting cells.

3. •In 1665, Robert Hooke published
Micrographia, a book filled with
drawings and descriptions of the
organisms he viewed under the
recently invented microscope. The
invention of the microscope led to
the discovery of the cell by Hooke.
While looking at cork, Hooke
observed box-shaped structures,

4. which he called “cells” as they
reminded him of the cells, or rooms,
in monasteries. This discovery led to
the development of the classical cell
theory.
The classical cell theory was
proposed by Theodor Schwann in
1839.

5. There are three parts to this theory.
The first part states that all organisms
are made of cells.The second part
states that cells are the basic units of
life. These parts were based on a
conclusion made by Schwann and
Matthias Schleiden in 1838, after
comparing their observations of plant
and animal cells.

6. The third part, which asserts that
cells come from preexisting cells
that have multiplied, was described
by Rudolf Virchow in 1858, when he
stated omnis cellula e cellula (all
cells come from cells).

7. Since the formation of classical cell
theory, technology has improved,
allowing for more detailed
observations that have led to new
discoveries about cells. These
findings led to the formation of
the modern cell theory, which has
three main additions: first,
that DNA is passed

8. between cells during cell division;
second, that the cells of
all organisms within a
similar species are mostly the
same, both structurally and
chemically; and finally, that energy
flow occurs within cells.