1. The history of cell theory began with early observations of cells in the 17th century by Robert Hooke and refinements in the 19th century by Theodor Schwann and Matthias Schleiden. 2. Schwann and Schleiden developed the cell theory which stated that the cell is the basic unit of structure and function in living things. 3. Modern cell theory recognizes that all living things are composed of cells, cells arise from preexisting cells, and the cell is the basic functional unit of life.

1. CELL
1

2. HISTORY OF A
2

3. 3

4. HISTORY OF A CELL
ROBERT HOOKE
4

5. In 1838, Theodor Schwann and
Matthias Schleiden were
enjoying after-dinner coffee and
talking about their studies on
cells. It has been suggested
that when Schwann heard
Schleiden describe plant cells
with nuclei, he was struck by
the similarity of these plant
CELL THEORY DEVELOPMENT
5

6. THREE CONCLUSIONS
ABOUT CELLS :
1.The cell is the unit of structure,
physiology and organization in living
things.
2.The cell retains a dual existence as a
distinct entity and a building block in the
construction of organisms.
6

7. The third statement was denounced later when Rudolph
Virchow’s experiment made a powerful statement.
The salient features of Cell Theory in its
present form are:
1. All organisms are composed of one or
more cells.
2. All cells arise from pre-existing cells.
3. Cell is the basic structural as well as
7

8. CELL TYPES AND

9. • These are small cells from
the Bacteria and Archaea
domains. They do not
contain a membrane-bound
nucleus or other membrane-
bound organelles. Their
activities related to life
functions are accomplished
9
PROKARYOTIC CELLS

10. • These are complex cells
in which a membrane-
bound nucleus and
membrane-bound
organelles are present.
Example of these cells
are of Protista, Plantae,
Animalia and Fungi.
10
EUKARYOTIC CELLS

11. PARTS OF
ANIMAL AND PLANT
CELLS

12. PLANT AND ANIMAL CELL
12

13. THREE BASIC STRUCTURES OF CELLS :
1.CELL
MEMBRANE
• The outer
boundary of
the cell.
13

14. THREE BASIC STRUCTURES OF CELLS :
2. NUCLEUS
• The control
center of the
cell.
14

15. THREE BASIC STRUCTURES OF CELLS :
3. CYTOPLASM
• The material between
the cell membrane
and the nucleus.
15

16. 16

17. ORGANELLES
17
• Cells have parts
that perform
specific jobs. They
perform the actual
work of a cell.
These organelles
are formed from
various molecules.

18. 18
ORGANELLES
• Some of the functions carried out by the
organelles are the protein building,
information storage, waste disposal,
transport of materials, and energy capture
and release. Single-celled organisms also
have organelles that are similar to those in
more advanced organisms to complete their
life processes. Several enzymes are needed

19. ORGANELLES AND THE FUNCTIONS
19

20. 20
MITOCHONDRIA
• A sausage-shaped organelles, they are
commonly called “power houses” of the
cell. They trap the energy that results
when food is broken down. Mitochondria
provide energy for the cell. Some types
of the cells are more active than others,
that’s why they can have more
mitochondria.

21. 21
THINK ABOUT THIS?
Why might a muscle cell have more
mitochondria than other cells?
• Muscle cells are always undergoing
some type of movement. Muscles are
also the ones exposed to strenuous
activities like doing some household
chores, running, walking, etc.

22. 22
Do you know that cells also
produce wastes?
• In cytoplasm, structures called
lysosomes contain chemical that digest
wastes and worn-out/damaged cell parts.
When a cell dies, chemicals in the
lysosomes act to quickly break down the
cell

23. 23
VACUOLES
• Serves as a
storage areas in
cells. They may
store water , food,
or waste products.
In plant cells,
vacuole are big. In
animal cell,

24. 24
CELL WALL
• The outer covering
of the plant cell is
not soft and thin.
Instead, it is
surrounded by a
rigid/tough
structure that

25. 25
CHLOROPLAST
• Substances
inside the
chloroplast help
a green plant
trap the sun’s
energy and then
produce food.

26. WHY CELLS CALLED
THE BASIC UNIT OF
LIFE ?

27. 27
WHY CELLS CALLED THE BASIC UNIT
OF LIFE ?
Cells make up the smallest level of a
living organism such as yourself and
other living things. The cellular level of an
organism is where the metabolic
processes occur that keep the organism
alive. That is why the cell is called the

28. 28
• Humans need various systems for
circulation, coordination, digestion,
excretion, immunity, movement,
reproduction, and respiration. The
systems perform the life processes.
WHY CELLS CALLED THE BASIC UNIT
OF LIFE ?

29. DO YOU KNOW?
Biggest cell in our body
is MEGAKARYOCYTE
( a kind of blood cell) ,
which have a diameter
of 0.2mm. They are
found in bone marrow
to prevent bleeding.

30. The smallest and
longest living cell in
our body is the
brain cell
DO YOU KNOW?