This document discusses the levels of biological organization from cells to the biosphere. It begins by defining key terms like organelles, unicellular, and multicellular cells. It then covers the discovery of cells by pioneers like Hooke, Van Leuwenhoek, Brown, Schleiden, Schwann, and Virchow and their contributions to developing the cell theory. The cell theory states that all living things are composed of cells, cells come from pre-existing cells, and cells are the fundamental units of life. The document also defines unicellular as single-celled and multicellular as composed of many cells. It includes an activity where students answer questions in groups about cells.

1. Levels of Biological
Organization

3. L E C L S
CELLS

4. O G R N A L E L S
E
ORGANELLES

5. AINAML
ECLSANIMAL CELLS

6. TNLAP
LECLSPLANT CELLS

7. UINECLULAL
R
UNICELLULAR

8. MLUITECLULA
LRMULTICELLULAR

9. What do you think is our lesson
for today?

10. Today I will:
Discuss the discovery of the cell and
the development of the cell theory;
Describe the unicellular and
multicellular cells; and
Realize the fruits of patience and
perseverance.

11. INSTRUCTION:
•Go to your respective groups for an
activity. Bring with you your lecture
notebook and ballpen.

12. Read the selection
“The Development of Cell
Theory”
and prepare for questions
that will be answered by
group.

13. •Have you ever seen a cell?
•When?
•What do you remember about
it?

14. •The cell is the smallest unit of matter that
can carry on all the processes of life.
•Most cells are visible only with a
microscope.
•Cells contain a variety of internal
structures called ORGANELLES.

15. According to the selection, who were
the pioneers in the discovery of cells
and what are their contributions?

16. ROBERT HOOKE
(1635 –1703)
An Englishman, he
coined the term “cell”
and was responsible for
introducing cytology as
a discipline in biology.

17. ANTON VAN
LEUWENHOEK (1632 –
1723)
A Dutch naturalist, he
discovered bacteria and
other microscopic
organisms in rainwater. He
studied the structure of
plant and animal cells.

18. ROBERT BROWN
(1773 – 1858)
A Scottish botanist,
he discovered the
presence of nuclei
within cells.

19. MATTHIAS SCHLEIDEN
(1804 – 1881) &
THEODOR SCHWANN
(1810 – 1882)
The German botanist
and zoologist,
respectively,
introduced the concept
that all plants and
animals are made up of
cells.

20. RUDOLF VIRCHOW
(1821 – 1902)
A German physician, he
found that cells divide to
form new cells. He
concluded that cells
come from preexisting
cells.

21. State the CELL
THEORY.
According to the cell theory, proposed over 150
years ago:
• All living things are composed of cells.
• All cells come from pre-existing cells.
• Cells are the fundamental (smallest) units of
life.

22. WHAT IS A UNICELLULAR?
Organisms that are
made-up of only one
cell.

23. WHAT IS A MULTICELLULAR?
Organisms that are
composed of
countless cells.

24. WHAT DO YOU THINK:
•Are cells alive?
•Why do you think this is true?
•Where are cells located in your
body?

25. PREPARE FOR A
QUIZ

26. ¼ Sheet of paper: Match column A
with column B. Write letters only.
Column A Column B
___16.Matthias Schleiden
___17. Robert Brown
___18. Rudolf Virchow
___19.Theodore Schwann
___20. Robert Hooke
a. discovered the nucleus.
b. concluded that plants are
composed of cells.
c. the first to use the term “cell”.
d. stated that animals are made up
of cells.
e. stated that all cells come from
pre-existing cells.

27. 1.Organelles
2.Cell
3.Tissues
4.Organ
systems
5.Population
6.Biosphere
7.Organs
8. Biosphere
9. Ecosystem
10. Population
11. Organism
12. Organ
Systems
13. Organ
14. Tissue
15. Cells
16. b
17. a
18. e
19. d
20. c

29. ASSIGNMENT:
Research more on the cell
and how the development of
instruments and techniques
contributed to its study.