Cell hap

Prepared by
Ms. Nisha S. Mhaske
M.Pharm (Q.A.T)
Lecturer, PRES’s COPD, Chincholi.
Email : nisha.mhaske@pravara.in

 It is a basic living structural and functional unit of body.
 The cell can be studied under two major parts- cell membrane &
cell organelles.
 The living cells are made up of a substance called protoplasm,
which is slightly opaque, colorless & soft jelly like substance
consisting of water and large no. of substances in solution or
suspension.
 Protoplasm within the cell and outside the nucleus is called
cytoplasm.

 Outermost layer consist of cytoplasmic membrane.
 It consist of bio-molecular layer of lipid molecule, coated
with a protein layer on each surface.
 It is composed of various layers.
 It has small pores and acts as selective sieve through which
certain substances are allowed to enter into the cell and the
transport outside the cell few other substances in the form
of excretion.

 It has active transport processes across the cell membrane.
 Lipids mainly are phospholipids, cholesterol and glycolipids.
 Also some carbohydrates are involved in the cell membrane.
Approximate composition is as follows
Proteins 55 %
Phospholipids 25 %
Cholesterol 3 %
Other lipids 4 %
Carbohydrates 3 %

 Principally cell membrane is made up of lipids and
proteins.
1. Membrane Lipids
 All membrane lipids are amphipathic.
 It is divided into the hydrophilic polar head and the
hydrophobic hydrocarbon tails.
 The glycolipids are sugar containing lipids.
 Cholesterol is more abundant towards the outside of the
plasma membrane.

2. Membrane Proteins
 It is studied under 2 main forms
a. Integral proteins/
transmembrane proteins
b. Peripheral proteins
i. Channel protein
ii. Carrier protein
iii.Receptor protein
iv.Pumps

a) Integral proteins/ transmembrane proteins
i. Channel protein
 They are responsible for the transfer of small water-
soluble substance.
ii. Carrier protein
 They helps to transfer materials across the bilayer through
active transport mechanism.
iii. Receptor protein
 These bind with different neurotransmitters or other
chemical substances leading to the changes in
intracellular reactions.
iv. Pumps
 These are also proteins and they actively transfer the ions
across the bilayer against the concentration gradient.

b. Peripheral Protein
 They are also called as extrinsic protein.
 They do not penetrate the lipid membrane completely, but
remain attached to the integral proteins.

 They act as the receptor, some are enzyme.
 It having small pores and active transport process and that
will help in the transferring of substances across the cell
membrane.

 Nucleus
 Endoplasmic Reticulum (ER)
a. Smooth endoplasmic reticulum or Agranular ER
b. Rough Endoplasmic reticulum or granular ER
 Ribosomes
 Golgi apparatus or Golgi bodies
 Mitochondria
 Lysosomes
 Centrioles
 Microtubules

 Central mass within the cell called nucleus.
 Protoplasm inside the nucleus called nucleoplasm
 The eukaryotic nucleus is bound by double membrane, called
nuclear membrane
 And this nuclear membrane externally continuous with the
endoplasmic membrane.
 Nuclear membrane contain pores.

 Nucleus contain nucleoli (Singular is nucleolus)
 Nucleolus is cluster of DNA
 Nucleus contain 46 Chromosomes which contain genes, which
are responsible for the maintenance of the cellular structure as
well as for the control of the cellular activities.
 Nuclear membrane has pores, the pores allow transfer of water
and water soluble material.

 Layers of plasma membranes are folded inwards and forms
a vesicles are called endoplasmic reticulum.
 It is largest membrane in eukaryotic cell.
 It is of 2 types:-

 The amount of smooth endoplasmic reticulum, varies from
cell to cell.
 Function of Smooth Endoplasmic reticulum
 Synthesis of fatty acids and phospholipids
 Certain enzymes present in smooth ER, modify and detoxify
many toxic chemicals and carcinogens.

 Those endoplasmic reticulum carries granules and that
granules are called as Ribosome.
 And hence that ER called as Rough ER because
appearance is granular and rough.
 Function of Rough Endoplasmic reticulum
 Because of presence of ribosome, rough ER is responsible
for synthesis of certain proteins.
 Also responsible for production of antibodies.

 Ribosomes are small granules which are made up of ribosomal
RNA (rRNA) and many ribosomal proteins.
 They are made up of 2 subunits; the smaller one and the larger
one both containing RNA of smaller and larger size
respectively.
 Ribosomes are of 2 types
 One attached to endoplasmic reticulum
 Others observes free in cytosol, called cytoplasmic or free
ribosomes.

 Synthesis of protein
 Free ribosomes produces proteins to be utilized by
the cell itself.

 Tightly packed system of smooth-surfaced vesicles
near the nucleus called Golgi apparatus.
 It is made up of continuous series of flattened
membranous sacs.
 The stack of Golgi sacs has 2 defined regions- Cis &
Trans.
 The proteins from endoplasmic reticulum come to he
Golgi apparatus through transfer vesicles, and fuse
with the sacs of cis region.
 These raw proteins are then carried to trans region.

 They stores proteins and is also responsible for
modifying them.
 Through secretary vesicles these proteins are secreted
outside the cell when needed.

 It is called as powerhouse of cell.
 Intracellular organelles which are surrounded by double
unit membrane.
 The number of mitochondria vary from cell to cell.
 It can be less than hundreds, to more than several
thousand, depending on energy requirement of cell.
 The mitochondria is composed of two lipo-protein
membranes.
a. The outer one is intact and covers the whole structures
b. Inner one is folded internally to form shelves.

 Many oxidative enzymes present in mitochondria.
 These enzymes causes oxidation of nutrient, CO2 & water.
 Releases energy which is utilized in formation of ATP
(Adenosine Triphosphate)
 Hence, mitochondria are called as powerhouse of cell.
Causes Oxidation of
Energy
Mitochondria
Oxidative
Enzymes
Nutrient, CO2 &
Water
That energy is
utilized in the
formation of ATP

 It is also intracellular structure surrounded by a
lipoprotein unit membrane.
 It is filled with a large number of small granules
which are aggregates of digestive enzymes.
 These digestive enzymes can digest proteins, nucleic
acid, mucopolysachharides and glycogen.

 Each cell contains two centrioles which are small
cylindrical structures.
 Two centrioles, together form the centrosome.
 Situated near the nucleus.
 Important role in cell division.

 Many cells contain fine tubular structures called
microtubules which are arranged in bundles.
 Provides rigid physical structures for certain parts of
cells like cilia.
 They are also used for movement of cytoplasm.

 Human Anatomy & Physiology, by Rahul Phate, Career
publications, First edition-Jan 2004.
 Human Anatomy & Physiology, by S.B.Bhise &
A.V.Yadav, Nirali Prakashan, 25th edition-July 2013.

Cell hap

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

Similaire à Cell hap

Similaire à Cell hap (20)

Plus de Nisha Mhaske

Plus de Nisha Mhaske (20)

Dernier

Dernier (20)

Cell hap