this presentation providing about the cell .Cell is the basic living, structural, and functional unit of the body.
Cells are grouped together to form tissues, each of which has a specialized function, e.g.- Bone and blood tissue.
Different tissues are grouped together to form a organs, e.g. liver, stomach, and kidney etc.
Organs are grouped together to form a system, each of which performs a particular function responsible for maintaining homeostasis .
e.g. Urinary system, Respiratory system etc.
2. Cell
Cell is the basic living, structural, and functional unit of the body.
Cells are grouped together to form tissues, each of which has a specialized
function, e.g.- Bone and blood tissue.
Different tissues are grouped together to form a organs, e.g. liver, stomach,
and kidney etc.
Organs are grouped together to form a system, each of which performs a
particular function responsible for maintaining homeostasis .
e.g. Urinary system, Respiratory system etc.
4. Cytology
Cytology is the branch of science that deals with the microscopic study of
cells, their original structure and function .
The cell is divided into two major parts :
Plasma membrane
Sub-cellular organelles :
5. Plasma membrane
The thin barrier that separates the internal components of the cell from the
extracellular materials and external environment is the plasma membrane
6. Composition of Membrane:
The cell membrane is principally made-up of lipids, proteins and
carbohydrates.
The lipids are mainly phospholipids, cholesterol and glycolipids.
The membrane linked to either proteins or lipids.
8. Cytoplasm
It is a gel like substance enclosed within the plasma membrane .
Cytoplasm is transparent, viscous gel like fluid.
It containing 75 to 90% of water, suspended and dissolved components such as
proteins, lipids, and carbohydrate, different inorganic substances and salts.
Function of cytoplasm
• The cytoplasm functions to support and suspend organelles and cellular
molecules.
• Many cellular processes also occur in the cytoplasm, such as protein
synthesis, the first stage of cellular respiration (known as glycolysis), mitosis,
and meiosis.
9. Nucleus
The nucleus is usually a spherical or oval in shape.
It is the largest structure of the cell.
The nuclear membrane is double membrane which separates the nucleus
from the cytoplasm.
The nuclear membrane contains pores in membrane where inner and outer
parts of membrane fuses.
It contains a spherical structure called as nucleolus.
10. Functions of Nucleus
• It controls the heredity characteristics of an organism.
• It main cellular metabolism through controlling synthesis of particular enzymes.
• It is responsible for protein synthesis, cell division, growth and
differentiation.
• Stores heredity material in the form of deoxy-ribonucleic acid (DNA) strands.
11. Ribosomes:
These are tiny spheres that contain ribosomal RNA and several ribosomal
proteins
These are the site for proteins synthesis.
These are made up of two sub-unit;
Smaller sub-unit (40s)
Larger sub-unit(50s)
Ribosomes are two types :
Membrane bounded ribosomes
Free ribosomes
12. Endoplasmic Reticulum(ER)
The E.R is a pattern of membrane enclosed channels called as cisterns of
varying shapes.
It is an interconnected network of internal membrane .
Based on it association with ribosomes the ER is divided into two types:
Rough ER
Smooth ER
13. Mitochondria
The Mitochondria is called the power house of the cell.
They are organelles that act like a digestive system which takes in nutrients,
breaks them down, and creates energy rich molecules for the cell.
The biochemical processes of the cell are known as cellular respiration.
The mitochondria consist of two lipoprotein Membranes :
Outer mitochondrial membrane :
Inner mitochondrial membrane :
The region between the two membrane is called as the intermembrane space
14. Golgi complex
Golgi Apparatus or complex is Present near the nucleus.
It consists of four to six flattened sacs called as cisterns placed upon each
other like a pile of plates with expanded bulges at their ends.
The stack of Golgi sacs has two define regions cis and trans.
The Golgi apparatus gathers simple molecules and combines them to make
molecules that are more complex.
It then takes those big molecules, packages them in vesicles, and either stores
them for later use or sends them out of the cell.
It is also the organelle that builds lysosomes (cell digestion machines).
15. Lysosome
Lysosomes are specialized vesicles within cells that digest large molecules
through the use of hydrolytic enzymes.
It contains 60 kinds of powerful digestive and Hydrolytic enzymes that can
Hydrolyse large molecules such as RNA, DNA, proteins and lipids .
Vesicles are small spheres of fluid surrounded by a lipid bilayer membrane.
They have roles in transporting molecules within the cell.
Lysosomes are only found in animal cells; a human cell contains around 300 of
them
Lysosome enzymes work best at acidic PH= 5 and inactivated at neutral PH
value.
16. Transfer of material across the Plasma
membrane
Movement of small molecules across the membrane:
(A)Diffusion
Simple diffusion
Facilitated diffusion
Osmosis
(B)Active transport
Movement of large molecules across the membrane:
Endocytosis
Exocytosis
17. Simple Diffusion or Passive transport
Diffusion is the movement of a substance from an area of high concentration
to an area of low concentration without utilization of energy.
Diffusion happens in liquids and gases because their particles move randomly
from place to place.
Diffusion is an important process for living things; it is how substances move
in and out of cells.
Substance moves across the cell membrane by 3 basic mechanism:
The molecules remains in the aqueous phase and diffusion through aqueous
channels pores in the membrane.
The molecules leaves the aqueous phase on one side of the membrane , dissolved
in the lipid bilayer and cross it and again enters the aqueous phase on opposite
side of membrane .
The molecules combine with carrier molecules and help them across the cell
membrane .
18. Facilitated diffusion :
It is called as carrier as carrier –mediated diffusion .
The carrier protein facilitated the diffusion of the substances to the other
side membrane .
Energy is not required for the such transfer.
Many lipids insoluble substances like certain vitamins, glucose cross the
membrane by this process.
The transfer is in the direction of the contraction gradient , from higher
concentration to lower concentration .
19. Osmosis
Osmosis. The movement of water molecules through a selectively permeable
membrane from a region of high water concentration to low water concentration
is called osmosis.
A solution where there is higher water concentration outside the cell is called a
hypotonic solution
20. Active transport :
When the material is transport out against the concentration gradient i.e
from lower concentration to higher concentration with utilization of energy
then the process called as active transport .
Energy is obtained from the hydrolysis of ATP .
Active transport is of two types :
(a) Primary Active Transport :
(b) Secondary Active Transport :
21. Primary Active Transport :
Energy is derived from hydrolysis of ATP which changes the shape of carrier
protein .
The carrier protein pumps a substance across a plasma membrane against its
concentration gradient .
22. Secondary Active Transport
Secondary active transport, is transport of molecules across the cell
membrane utilizing energy in other forms than ATP.
This energy comes from the electrochemical gradient created by pumping ions
out of the cell. This Co-Transport can be either via antiport or symport.
23.
24. Endocytosis :
It is a transport mechanism that involves engulfing extracellular materials
within a segment of the cell membrane to form a vesicle called as vesicular
transport.
For example:
Macromolecular nutrients like facts and starches , oil soluble vitamin A , D , E,
K and drug such as insulin.
Endocytosis Includes:
Phagocytosis:
Pinocytosis:
25. Exocytosis
Undigested substance called as residual body excreted through the cell
membrane by a process as exocytosis,
Exocytosis' main purpose is to expel material from the cell into the
extracellular fluid.
This is the opposite of what occurs in endocytosis.
In exocytosis, waste material is enveloped in a membrane and fuses with the
interior of the plasma membrane.
26.
27. Cell division
Cell division is the process by which a parent cell division into two or more
daughter cells.
These cells divide once in approximately every 24 hours.
The duration of the cell cycle is can vary with organism and the cell type.
There are two types of the cell division:
Somatic cell division
Reproductive cell division
28. Somatic Cell division
The cell cycle is an orderly sequence of events by which a somatic cell
duplicates its contents and division into .
Human cell contains 23 pairs of chromosomes .
One member of each pair is inherited from each parent.
Somatic cells contain two sets of chromosomes ; they are called as diploid
cells, denoted as 2n.
The cell cycle is divided into two basic phases :
Interphase
Mitotic phase