The cell is the smallest structural, functional, and biological unit of all living organisms. It can capable of biosynthesis, replication and energy transformation.

1. ANIMAL CELL
Prof. Amol B. Deore
Department of Physiology
MVPS Institute of Pharmaceutical Sciences, Nashik

4. • The cell is the smallest structural, functional, and
biological unit of all living organisms which can capable
of biosynthesis, replication and energy transformation.
• They are often called the ‘building blocks of life’.
The cell

6. Cytology is the scientific
study of cellular structure
and function. Organisms
can be classified as
unicellular (consisting of
a single cell; including
bacteria) or multicellular
(including plants and
animals).
While the number of cells
in plants and animals
varies from species to
species, humans contain
about 100 trillion (1014)
cells.

7. All cells arise from existing cells by the process of
cell division, in which one cell divides into two
identical cells.
Different types of cells fulfil unique roles that
support homeostasis and contribute to the many
functional capabilities of the human organism.

8. ■ Most plant and animal cells are visible only under the microscope, with
dimensions between 1 and 100 µm.
■ Animal cell contains membrane bound nucleus, it also contains other
membrane bound cellular organelles.These cellular organelles carry
out specific functions that are necessary for the normal functioning of
the cell.

9. Typical animal cell

10. PLASMA MEMBRANE
■ A biological membrane that surrounds
the cytoplasm of a cell which covers the
cell.
■ In short, it is the outer boundary of the
cell. It is a thin, elastic structure about 7.5
to 10 nm in thickness.
■ It separates the internal environment
(inside the cell) from the external
environment (outside the cell).

11. ■ The plasma membrane is made up of lipid bilayer, which
contains lipid molecules— phospholipids, cholesterol, and
glycolipids.
■ The bilayer arrangement found because the lipids are
amphipathic molecules, which means that they have both polar
and nonpolar parts.
■ The polar part is made up of phosphate containing “head,”
which is hydrophilic (hydro means water; philic means loving).
■ The nonpolar part is made up of two long fatty acid “tails,”
which are hydrophobic (-phobic means fearing).

13. FUNCTIONS
• The membrane allow the passage of different nutrients and
electrolyte ions into and out of a cell.
• The plasma membrane also plays a vital role in
communication between cells to cells.
• Plasma membranes also contain proteins that allow cells to
detect external signalling molecules such as hormones.

14. CYTOPLASM
■ The intracellular substance in which all cell organelles are
suspended is known as cytoplasm.
■ Cytoplasm is a viscous, transparent, gel like semisolid fluid
containing 75-90% water, proteins, carbohydrates, lipids, organic
substances including amino acids, sugars polysaccharides and
inorganic substances such as mineral ions.

15. NUCLEUS The nuclear membrane is composed of
two membranes i.e. inner and outer
nuclear membranes.
The inner membrane surrounds and
contains the nucleoplasm and its
materials.
The outer membrane is continuous with
the endoplasmic reticulum (ER).
Both are made up of phospholipid bilayers
and nuclear pores.
These pores allow the passage of
materials from the nucleoplasm into the
cytoplasm.
For example, messenger RNA (mRNA)
and various proteins.

16. NUCLEOPLASM
The fluid medium of the nucleus is called the
nucleoplasm.
It consists of proteins, the nucleic acids DNA, RNA,
enzymes, and other chemicals of the nucleus.
CHROMATIN
The cells of the human body contain 46
chromosomes (22 pairs of autosomes and one pair
of sex chromosomes: one member of each pair
comes from the father and one member from the
mother).

17. The egg cell (ovum) and the sperm cell contain one half that number or 23
chromosomes.
Chromosomes are supercoiled structures of chromatins and act as genetic
material of the cell.
Each chromatin consists of million numbers of DNA molecules.
Each DNA molecule is made up of sequence of amino acids.

18. ENDOPLASMIC RETICULUM
■ It is a complex system composed of membrane
bound cavities.
■ The cavities are channel-like structures called as
cisternae which are used to store and transport
materials made by the cell.
■ The ER is attached to the outer membrane of
the nuclear membrane.
■ The endoplasmic reticulum ER is divided in to
two types.
1] Rough (granular) ER composed of
ribosomes;
2] Smooth (agranular) ER has no ribosomes.

20. Rough ER
All cells have a rough endoplasmic reticulum.
It is also called as granular endoplasmic reticulum because it contains ribosomes.
The rough ER is the site of protein biosynthesis.
The cavities of the rough ER work in the separation and transport of these proteins.

22. Smooth ER
Smooth (or agranular) endoplasmic reticulum does not have attached
ribosomes. It also differs in function.
Only certain cells have the smooth ER including adrenal gland, sex glands
(ovary and testes), adipose tissues, liver, small intestine, pancreas etc.
Smooth ER performs biosynthesis of steroidal hormones, sex hormones
digestive enzymes, fatty acid, phospholipids, triglycerides and cholesterol.
Enzymes within the smooth ER can detoxify a variety of chemicals
including alcohol and certain drugs.

23. RIBOSOMES
■ There are many, many ribosomes in the cell because they are so essential to cell
function.
■ Free ribosomes are small tiny granules distributed throughout the cytoplasm and
some are attached to the rough-granular endoplasmic reticulum.
■ They are the actual sites of protein synthesis. Free ribosomes synthesise proteins
which are utilized for the metabolism of the cell and growth.
■ The attached ribosomes are the sites for the protein synthesis to be secreted by the
cell. Ribosomes are composed of ribosomal RNA (rRNA) and several ribosomal
proteins.
■ Messenger RNA (mRNA) attaches to ribosomes during proteins synthesis.

24. GOLGI APPARATUS
■ The Golgi apparatus is also called as
Golgi body.The shape of Golgi
apparatus is like a tea cup. It may be
attached to the endoplasmic reticulum.
■ They are covered by two membranes:
Inner membrane and outer membrane.
■ The inner membrane is composed of
number of folds/cavities called as
cisterns.
■ The Golgi apparatus also consists of
secretory vesicles.

26. ■ Carbohydrates synthesis like glucose takes place in the Golgi
apparatus.
■ Proteins formed by ribosomes are stored in the secretory vesicles of
Golgi apparatus.
■ In the pancreas, the digestive enzymes are stored in Golgi apparatus
and then are secreted.
■ The secretory vesicles of Golgi bodies which are composed of digestive
enzymes further develop in to Lysosomes.
■ The Golgi bodies also perform processing, sorting, packaging and
transport of lipids and proteins to cell membrane, lysosomes, and
secretory vesicles.
Functions

28. All the proteins exported from the cell follow the similar route
Ribosomes (site of protein synthesis) Rough ER Transport vesicles
Golgi apparatus Secretory vesicles
Proteins release to outside of the cell by exocytosis

31. MITOCHONDRIA
Mitochondrion is a bean-shaped
organelle that acts as a “energy
transformer” of the cell.
They are the site of cellular
respiration and energy
metabolism.
They act by generating ATP, an
energy rich molecule.

32. They are usually 3-4 µm in size.The number of mitochondria varies in
different types of cells.
Cells with high metabolic activity have high number of mitochondria,
while those with low metabolic activity have a lower number.
There are about 1600-2000 mitochondria present in liver cells, muscle
cells, kidney, while sperm cells contain only 20-24.
Mitochondria are composed of two membranes.The outer membrane
is smooth gives its capsule shape to mitochondrion;
while the inner membrane is arranged in a series of folds called as
cristae.The central cavity of a mitochondrion is called as the matrix.

34. The matrix contains DNA, some proteins, ribosomes
and several enzymes required for metabolism of
carbohydrates, lipids and amino acids (citric acid cycle,
β-oxidation, oxidative phosphorylation).
These reactions convert nutrient molecules (such as
glucose) intoATP, which provides cellular energy to the
cell.
Oxygen molecules are required during cellular
respiration, which is why you must constantly breathe
it in.

36. The cellular respiration can be stated as follows:
Food (like glucose) + oxygen Energy + waste+ water
C6H12O6 + 6O2 ATP + 6CO2 + 6H2O
Most of the energy-producing reactions, which occur in the
mitochondria, take place on the surface of the cristae.
For this reason, the mitochondria are known as the
powerhouses of the cell.