Perfect notes to become topper.

1. THE FUNDAMENTAL UNIT OF
LIFE- “THE CELL”

2. Learning Objectives
 Students will be able to learn about discovery
and definition of cell.
 Students will be able to understand the type of
cells.
 Student will be able to differentiate between
prokaryotic and eukaryotic cells.

3. Discovery of the cell
 In 1665, ROBERT HOOKE observed the section of cork under
microscope and saw ‘honeycomb’ like structures.
 These structures were called ‘CELLULAE’ by him which later become
‘CELL’(L. cella = compartment).
 He describe these ‘dead’ cells in his book – ‘MICROGRAPHIA’.

5. Discovery of the cell
 In 1670, ANTONY VON LEEUWENHOEK, a Dutch cloth
merchant and an amateur lens grinder, observed ‘LIVING
CELLS’ for the first time.
 In 1838, M. J. SCHLEIDEN and T. SCHWANN, proposed cell
theory which was extended by R. VIRCHOW in 1855 with the
statement- Omnis cellula e cellula.

6. Definition of the cell
 Cell is the structural and functional unit of the organism’s
body. OR
 Cell is the smallest, basic unit of life/living being that is
responsible for all of life processes.
Diag. Different types of Cells

7. Who discovered the living cells
for the first time? Can you write
the name ?
Lets find out..

9.  Based on permeability membranes are of following types-
 (i) Impermeable membrane : These do not allow the passage of any
of the substances through them.
 (ii) Permeable membrane : These allow the passage of all types of
substances through them.
 (iii) Semi-permeable membrane : These are the membrane which
permit the movement of only solvent molecules and not the solutes .
 (iii) Selectively-permeable membrane :These are the membrane
which permit the movement of solvent molecules and selected solute
molecules .
Types Of Membranes

10. Plasma Membrane/ Cell Membrane/ Plasma
lemma-
It is a biological membrane that separates a cell’s
contents from its outside surrounding or external
environment.
Properties:
● Thin-walled, elastic
● Made up of proteins and lipids
● It is a living component of the cell
Functions:
● Protects the contents of the cell from its external
environment
● Its semi-permeable allows only selective materials
to flow in and out of the cell

15. TYPES OF THE CELL
 Based on nuclear organisation cells are of two types- Prokaryotic
and Eukaryotic cells.
 Prokaryotic cells- (Pro= primitive ; karyon= nucleus) cells
which lack prominent nucleus, e. g. bacteria, PPLO etc.

16. TYPES OF THE CELL
 Eukaryotic cells - (Eu= true; karyon= nucleus) cells which have
prominent nucleus, e. g. plant and animal cells etc.

17. Quiz Time
• Who discovered the living cells for the first time ?
• What is a cell?
• How will you differentiate between prokaryotic and
eukaryotic cells?

18. We know that all
living organism are
made of cell but
what are the
constituents of a
Cell?

19.  Organelle literally means “little organs”.
 An organelle is a subcellular structure that has one or more
specific jobs to perform in the cell, much like an organ does
in the body. Few examples are-
Cell Organelles

20. Concept map

25. DIFFERENCE

27. ENDOPLASMIC RETICULUM

39. Why is endocytosis found only in animal cell, and
not in plant cell?
• Animal cell is having only plasma membrane as outer
covering, and it is soft and flexible, thus invagination
of plasma membrane is possible.
• Plant cell is having outer cell wall, which is tough,
rigid and flexible.
• So, invagination or infolding of plasma membrane is
hindered because of cell wall.