1. CELL : STRUCTURE AND FUNCTION

2. INTRODUCTION
The cell is the basic structural, functional, and biological unit of all known living organisms.
The buildings built of similar bricks, have different designs, shapes and sizes. Similarly, in the living world, organisms differ from one another but all are made up of cells.

3. ONION CELL UNDER MICROSCOPE
CELL MEMBRANE
NUCLEUS
CYTOPLASM

4. DISCOVERY OF CELL In 1665, ROBERT HOOKE observed
slices of cork under a simple
magnifying device.
Cork is a part of bark of tree.
He noticed partitioned boxes or
compartments in the cork slice.
These boxes appeared like a
honeycomb.
Hooke coined the term ‘cell’ for
each box.

5. NUMBER OF CELL ORGANISM UNICELLULAR MULTICELLULAR
All living organism are divided into two types , based on number of cell :
ORGANISM
UNICELLULAR
MULTICELLULAR
Organisms made up of single cell are called unicellular ( uni : one; cellular : cell) organisms
Example : amoeba , paramecium etc.
Organisms made of more than one cell are called multicellular (multi : many; cellular : cell) organisms
Example : human being , grass , elephants etc.

6. SHAPE OF CELL Spherical shape Spindle shape Long branched shape RBC
MUSCLE CELL
NERVE CELL

7. SHAPE OF CELL Amoeba has no definite shape, unlike
other organisms. It keeps on changing
its shape. The projections of varying
lengths protruding out of its body. These
are called pseudopodia .These projections
appear and disappear as Amoeba moves
or feeds.
White blood cell (WBC) in human
blood is another example of a
single cell which can change its
shape .

8. SIZE OF CELL The size of cells in living organisms may be as small
as a millionth of a metre
(micrometer or micron) or
may be as large as a few cm.
The smallest cell is 0.1 to 0.5
micrometer in bacteria.
The largest cell measuring
170 mm ×130 mm, is the egg
of an ostrich.

9. PARTS OF CELL
Cell membrane
Cytoplasm
Nucleus

10. CELL MEMBRANE The cell membrane also known as the plasma membrane or
cytoplasmic membrane.
Cell membrane is a biological
membrane that separates the
interior of all cells from the
outside environment.
The boundary of the plant cell is the cell membrane covered by another thick covering called the cell wall. It provides the cell with both structural support and protection.
Cell wall is absent in animal cell.

11. CYTOPLASM It is the jelly-like substance present
between the cell membrane and
the nucleus.
Various organelles of cells are
present in the cytoplasm. These
are mitochondria, golgi bodies,
ribosomes, etc.
Most cellular activities such as metabolic pathways including glycolysis, and processes such as cell division occur in cytoplasm.

12. NUCLEUS
The cell nucleus is a membrane bound structure that contains the cell's hereditary information and controls the cell's growth and reproduction.
Nucleus is separated from the cytoplasm by a membrane called the nuclear membrane. This membrane is also porous and allows the movement of materials between the cytoplasm and the inside of the nucleus.
With a microscope of higher magnification, we can see a smaller spherical body in the nucleus. It is called the nucleolus.

13. In addition, nucleus contains thread-like structures called chromosomes. These carry genes and help in inheritance or transfer of characters from the parents to the offspring.
The chromosomes can be seen only when the cell divides.
Nucleus, in addition to
its role in inheritance,
acts as control center of
the activities of the cell.

14. On the presence of nuclear membrane organism are divided into two types:
1. Prokaryotes : The cells having nuclear
material without nuclear membrane are
termed prokaryotic cells. The organisms
with these kinds of cells are called prokaryotes
(pro : primitive; karyon : nucleus). Examples are
bacteria and blue green algae.
2. Eukaryotes : The cells, like onion cells and
cheek cells having well organised nucleus
with a nuclear membrane are designated as
eukaryotic cells. All organisms other than
bacteria and blue green algae are called
eukaryotes.(eu : true; karyon: nucleus).
HYDRA
BIRDS

15. Comparison between animal cell and plant cell

16. bibliography
Science NCERT class 8th
Google pictures

17. THANK YOU