This lesson introduces 9th grade students to the basic concepts of cells, including: 1) Cells are the smallest and basic unit of structure and function of all living organisms. 2) Cells were first observed by Robert Hooke in 1655 and further studied using microscopes invented by Anton Van Leeuwenhoek and others. 3) Cells vary greatly in size but are generally microscopic, ranging from 0.1 to 18 micrometers. 4) The modern cell theory postulates that all living things are composed of cells, cells are the basic functional units of life, and new cells are produced from existing cells.

1. A.I.C.E.S.R.
B.Ed. Lesson Note
Name of Professor: S. S. Chepe Subject Lesson No.:
Name of School: - Lesson No.:
Std: 9th
Div: A Time: 1.00-1.30 P.M. Date: 16/8/14 Type of Lesson: Integrated
Teaching Subject: Science and Technology Teaching Unit: Cell: The Unit of Life
Content Teacher Activity & Procedure Student
Role/Activity
Skills
Presentation-
Sub unit 1- Concept of
cell-
Sub unit 2- Cells- How
many?
Good afternoon students. Students when you
come to school what do you observe?
Yes, many vehicles, people, houses, shops,
vendors, etc.
You must have also seen some bungalows, small
buildings or towers.
What is the common thing between the houses?
Do they all look same or are they different?
Do they have any common property?
What are the basic building blocks used to
construct them?
As we know that every structure is made up of
some blocks. Same is true for living beings. There
are millions of living beings on the earth but still
they all have the same building blocks known as
‘cell’.
So let us study today the basic unit of life i.e. cell
in detail along with its Structural Organization
and function of each of the cell organelles.
Teacher writes the name of the topic on CB.
Students, the cells were discovered by Robert
Hooke in the year 1655. He observed a thin slice
of cork under self designed microscope. These
compartments of the cork were empty. He found
they resembled the structure of honey comb and
labeled them as ‘cells’, which in Latin means
‘small rooms’. But these cells were dead.
So every living thing, however different, is made
up of these separate tiny units called as cells.
Students, what do you think about the number of
cells in an organism?
Yes there can be an organism made up of single
cell known as unicellular organisms.
Name a unicellular organism.
There can be organisms with too many cells.
What do you think we can call them?
Yes they are multi-cellular organisms.
Larger the organism, larger the no. of cells in it.
Good
afternoon
They are made
up of bricks
There are few
cells.
multi-cellular
organisms
Set
Induction
Chalk Board
Work
Explanation

2. Subunit 3-
Morphology of cells-
(Size of the cell)
Invention of
Microscope
Sub unit 4-
Modern Cell Theory-
Co-operative Activity
The Modern Cell Theory
has following postulates-
1. All organisms are
made up of one or
more cells.
2. Cell is the structural
and functional unit of
life, i.e. all the vital
functions of an
organism occur within
the cells.
3. All cells arise from
pre-existing cells, i.e.
no cell originates
spontaneously but
comes into being only
by division of
cells.“Omnis celula a
cellula”. Every
Students, what do you think about the size of a
cell?
Are you sure the cells are always very minute?
Teacher shows an egg and says that even an egg is
a single cell.
An egg and amoeba both are single cells.
Size of the cell varies greatly (0.1m to 18 cm)
The unit used to measure size of the cell is
micrometer.
Why do you think that small size of cells is
beneficial?
Small size ensures greater surface area which in
turn ensures greater diffusion of the
nutrients into the cell.
What else can be the benefit of smaller cell size?
Yes, greater exchange of material in and out the
cells.
It also ensures easy repair of the damaged cells.
But how do we observe these cells by naked eyes?
What can we use to enable us observe the minute
cells?
Microscope was first invented by Anton Van
Leeuwenhoek in 1673.
It was only when the electron microscope was
invented in 1940, that the study of cells became
possible.
Teacher shows some slides of microscope.
Teacher shows the gradual modification and
advancement in the technique.
Teacher asks to describe what it looks like?
Teacher makes the students to form groups and
discuss among them-
What are organs made up of?
Cell is said to be structural unit of life. Why?
It is also said as the functional unit of life. What
could be the reason for it?
Students what do you think about formation of
new cells?
From where can new cells be formed in the body?
How?
What happens to the existing cells?
How can we say that heredity takes place?
The points discussed above are nothing but
Modern Cell Theory.
So students, today we have studied the Concept of
cell also the postulates of Modern Cell Theory.
They are very
minute
Students
discuss in
groups.
Questionning
Stimulus
Variation
Questionning

3. organism starts its life
as a single cell.
4. Cells contain the
hereditary information
is passed from cell to
daughter cell during
division.
5. All cells are basically
the same in chemical
composition.
We have seen that the size of the cell is from
fraction of millimeter to few centimeters. We have
also studied and observed various microscopes.
Teacher wipes the CB.
1. What is a cell?
2. Who invents cell?
3. How is simple microscope different than
compound, electron and stereo
microscope?
Teacher gives assignment- Prepare a chart
depicting the efforts of various inventors in
studying cells and their functions.
Closure
Assignment
Chalk Board Summary
Date:14/12/17 Subject: Science and Technology Std.-IX
Topic: Cell : The Unit of Life
 Cell=Small rooms(Latin)
 Unit to measure cell-1 micrometer = 1/1000
millimeter
 Cells were first discovered by-Anton Van
Leeuwenhoek in 1673.
Definition-Smallest structural and functional unit.