3. INTRODUCTION
All function of the bodies of living organisms
are performed by various system. These
systems are groups of organs performing one
principal junction. Each organ is made up of
tissues and each tissue is made up of cells.
The cell is the basic structure and functional
unit of life. Cells are also known as the
building blocks of life. They are of two types :
1) Animal cell
2)Plant cell
Animal cells are eukaryotic cells, or cells with
a membrane bound nucleus. It consists of:
4. NUCLEUS
It is a spherical body containing
many organelles, including
the nucleolus . The nucleus
controls many of the
functions of the cell &
contains DNA. The nucleus is
surrounded by the nuclear
membrane.
5. RIBOSOMES
Small organelles
composed of RNA-rich
cytoplasmic
granules that are
sites of protien
synthesis.
6. MITOCHONDRIA
It is a spherical to rod
shaped organelles
with a double
membrane. The
mitochondria
converts the energy
stored in glucose
into ATP for the cell.
7. LYSOSOME
These are the round
organelles
surrounded by a
membrane and
containing
digestive enzymes.
This is where the
digestion of cell
nutrients takes
place.
8. Golgi bodies
It is flattened, layered,
sac like organelle
that look like a
stack of pancakes
and is located near
the nucleus. It
produces the
membrane that
surrounds the
lysosomes.
9. Endoplasmic reticulum
They are of two types :
1) Rough
endoplasmic reticulum:
transports materials
through the cell &
produces protiens in sacs
called cristinae.
2) smooth
endoplasmic reticulum:
it contains enzymes and
produces and digests fats.
10. Plasma cell membrane
It is the thin layer of
protien and fat that
surrounds the cell.
The cell membrane
is semi permeable,
allowing some
substances to pass
into the cell and
blocking others.
11. conclusion
Cell is the structural & functional unit of life.
Structurally the cell is formed of three
major parts: plasma membrane ,
cytoplasm & its contents and nucleus. In
animal cell, cell wall is absent. Vacuoles
may present or absent. Animal cell possess
both centrioles and centrosomes. In animal
cell , food is present in the form of
glycogen , which is a polysacchride.
