In biology, cell theory is a scientific theory first formulated in the mid-nineteenth century, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells.

1. What makes you special
or unique?

2. CELL THEORY

3. OBJECTIVES:
At the end of this module, the Grade 12 students should be
able to:
1. State and explain the postulates of the cell theory.
2. Describe the structure and function of major and subcellular
organelles.
3. Realize one’s uniqueness.

4. Picture Analysis:

5. 1.What did you notice from the
picture?
2. What is the significant of having
division of labor in one family?

6.  Video Presentation about “Introduction to Cells”.
https://www.youtube.com/watch?v=gFuEo2ccTPA

7. 1. What is the message of the video?
2. What information/s did you get from the video?

8. CELL
“Prior to the invention of the very first
microscope, everything that could not be seen
by the naked eye was unexplainable”.

9.  The name CELL was
coined by an English
scientist,Robert Hooke
(1665).

10. Anton van Leeuwenhoek
1676 - Used a handmade
microscope to observe pond
scum & discovered single-
celled organisms. He called
them “animalcules”.

11. 1831, Robert Brown, , one of the
leading botanists of his time, was
able to compare different kinds of
plant specimens under the
microscope. He indicated that
there is one common thing about
them- they are all composed of
cells. Inside each cell is a dark
dense spot which he termed the
“nucleus”.
Robert Brown

12. Who came up with this theory?
Matthias Jakob Schleiden
All plants are
made of cells.
Onion skin cells

13. Theodor Schwann
Who came up with this theory?
Human red blood
All animals are
made of cells.

14. All cells come from
pre-existing cells.
Who came up with this theory?
Human red blood
Rudolf Ludwig Karl Virchow

15. CELL THEORY
1. All living organisms are made of cells.
2. The cell is the basic structural and
functional unit of life.
3. All cells come from pre-existing cells
(Omnis cellula e cellula)

16. - States that organisms can come from nonliving
sources.
- Contradicts the third postulate of cell theory.
• Francesco Redi (1668)
•John Needham (1745)
• Lazzaro Spallanzani (1729-1799)
• Louis Pasteur (1859)
Theory of Spontaneous Generation

17.  Romans - lens from the Latin word lentil
 1st Compound Microscope(1595) – Zacharias
Janssen
 Cellula (little rooms) – Robert Hooke (1665)
Microscope with higher magnification – Anton van
Leeuwenhoek
The invention of the Microscope and Discovery of the
Cell