UNIT-1 CELL AND FUNCTION BSC NURSING 1STYR ,1ST SEMESTER .

CELL
INTRO:The term ‘cell’ was coined by Robert Hooke in 1665 .The name cell is derived from
the Latin word ‘cellula’ , meaning ‘little room’. Cells are the fundamental building blocks
of all living organisms .Often called as “building blocks of life”. Whether an organism is
as simple as bacteria or as complex as a human, everything starts with a cell.
DEFINITION
Cells are defined as the smallest structural and functional units of life, capable of carrying out all
basic activities necessary for survival.
Each cell works like a tiny factory, producing energy, synthesizing proteins, and maintaining
life's essential processes
CELL THEORY
Proposed by Matthias Schleiden and Theodor Schwann in 1839.
The 3 main principles are
All the living organisms are made of cells
The cell is the basic unit of life
All the new cells arise from pre existing cells (RUDOLF VIRCHOW)
Contains 4 statement in addition to the original theory
The cell contains hereditary information (DNA) which is passed on from cell to cell during cell division
All cells are basically the same in chemical composition and metabolic activities
All basic chemical and physiological functions are carried out inside the cells
Cell activity is the basis for the life of organism
Cells perform essential functions that keep organisms alive. Some
vital functions include:
Energy production: Mitochondria convert glucose into ATP, which fuels cellular activity.
Protein synthesis: Ribosomes build proteins needed for growth and repair.
Reproduction: Cells divide to make more cells, enabling growth and healing (cell division).
Response to stimuli: Cells react to their environment (nerve cell)
Transport: Membranes regulate movement of substances using methods such as osmosis and active transport.
All cells share a few main components, though their complexity may differ.
The core structures found in most cells include:
Cell membrane: A protective barrier that regulates what enters and leaves the cell.
Nucleus: Usually present in eukaryotic cells, it stores genetic material (DNA).Cytoplasm: Fluid that fills the cell, where various organelles are suspended.
Organelles: Specialized structures like
Mitochondria, Ribosomes ,Endoplasmic reticulum, Golgi apparatus , Lysosomes
Also known as the plasma membrane or plasmalemma or unit membrane
A biological membrane that separates the interior of cell from the outside environment .
It is selectively permeable membrane
Structure:thickness-7-10 nanometer(nm)
It is composed of phospholipids ,cholesterol,protiens and carbohydrates.Protective: forms the outer boundary of the cell organelles
Selectively permeability : non-polar molecules such as co2,o2,n2,lipids,etc can move rapidly across the membrane.Polar molecules such as glucose,urea, ions,etc can penetrate the membrane much more slowly.Anchoring :it links adjacent cells together by junctional complexes to form tissues. Communication :it takes in foods and excretes wastes out of the cel

1. CELL BY URIKKHINBAM SONIA DEVI MSC (N)OBG

2. INTRODUCTION The term ‘cell’ was coined by Robert Hooke in 1665 .The name cell is derived from the Latin word ‘ cellula ’ , meaning ‘little room’. Cells are the fundamental building blocks of all living organisms .Often called as “ building blocks of life ”. Whether an organism is as simple as bacteria or as complex as a human, everything starts with a cell. DEFINITION Cells  are defined as the smallest structural and functional units of life, capable of carrying out all basic activities necessary for survival. Each cell works like a tiny factory, producing energy, synthesizing proteins, and maintaining life's essential processes

3. CELL THEORY Proposed by Matthias Schleiden and Theodor Schwann in 1839. The 3 main principles are All the living organisms are made of cells The cell is the basic unit of life All the new cells arise from pre existing cells ( RUDOLF VIRCHOW)

4. MORDERN COCEPT Contains 4 statement in addition to the original theory The cell contains hereditary information (DNA) which is passed on from cell to cell during cell division All cells are basically the same in chemical composition and metabolic activities All basic chemical and physiological functions are carried out inside the cells Cell activity is the basis for the life of organism

5. FUNCTIONS OF CELLS Cells perform essential functions that keep organisms alive. Some vital functions include: Energy production :  Mitochondria convert glucose into ATP, which fuels cellular activity. Protein synthesis :  Ribosomes build proteins needed for growth and repair. Reproduction:  Cells divide to make more cells, enabling growth and healing ( cell division ). Response to stimuli :  Cells react to their environment ( nerve cell ) Transport:  Membranes regulate movement of substances using methods such as  osmosis  and active transport.

6. STRUCTURE OF CELLS All cells share a few main components, though their complexity may differ. The core structures found in most cells include: Cell membrane : A protective barrier that regulates what enters and leaves the cell. Nucleus : Usually present in eukaryotic cells, it stores genetic material (DNA). Cytoplasm : Fluid that fills the cell, where various organelles are suspended. Organelles : Specialized structures like Mitochondria, Ribosomes ,Endoplasmic reticulum, Golgi apparatus , Lysosomes

7. CELL MEMBRANE Also known as the plasma membrane or plasmalemma or unit membrane A biological membrane that separates the interior of cell from the outside environment . It is selectively permeable membrane Structure: thickness-7-10 nanometer (nm) It is composed of phospholipids,cholesterol,protiens and carbohydrates.

8. FLUID MOSAIC MODEL –Singer and Nicholas IN 1972 A fluid bilayer of phospholipids with embedded protein resembling a mosaic . PHOSPHOLIPID BILAYER :The basic structure is a double layer of phospholipid molecules ,with their head (hydrophilic)facing outward and inward , and their tail (hydrophobic)pointing towards the centre.it creates a selective barrier PROTIENS- Protiens are embedded within or attached to the bilayer . integral protiens or intrinsic protein –located in the inner surface peripheral protiens or extrinsic protein - located on the outer surface

9. FUNCTION OF PLASMA MEMBRANE Protective: forms the outer boundary of the cell organelles Selectively permeability : non-polar molecules such as co2,o2,n2,lipids ,etc can move rapidly across the membrane.Polar molecules such as glucose,urea,ions,etc can penetrate the membrane much more slowly. Anchoring : it links adjacent cells together by junctional complexes to form tissues. Communication : it takes in foods and excretes wastes out of the cells.

10. NUCLEUS STRUCTURE: - Spherical structure surrounded by nuclear membrane -Made up of chromosomes,on which genes are present. -Contains a nucleolus. It synthesize the RNA for ribosomes. FUNCTION: -DNA in nucleus serves as a block for synthesis of RNA -Genes are units of hereditary characteristics . -It is concerned with cellular reproduction and multiplication.

11. MITOCHONDRIA STRUCTURE: Filamentous or globular in shape Occur in variable numbers from a few hundred to few thousands in different cells. Made up of outer and inner membrane .Inner membrane folded to form cristae Interior (matrix) of mitochondrion contains a large number of enzymes to burn glucose in oxygen FUNCTION Mitochondria are power generating units of the cells (POWER HOUSE OF CELL) Contain DNA and can synthesize proteins.

12. RIBOSOME STRUCTURE Have a structure composed of two subunits-a large and a small one ,which are made of ribosomal RNA and proteins LOCATION Some are freely floating in the cytoplasm Others can attached to the surface of endoplasmic reticulum FUNCTION Responsible for protein synthesis for the cell

13. GOLGI APPARATUS/GOLGI BODIES STRUCTURE Collection of membranous tubules and vesicles found always in the neighbourhood of the nucleus FUNCTION Wrapping and packaging department of the cell Produces secretion granules

14. ENDOPLASMIC RETICULUM STRUCTURE It is a complex series of tubules whose walls are made up of unit membrane. TYPES AND FUNCTION: Agranular or smooth ER contains no granules . It is site of steroid synthesis in steroid secreting cells and detoxification processes in other cells 2. Granular or Rough ER: Contains granules called ribosomes It is the site of protein synthesis

15. LYSOSOMES STRUCTURE: These are large irregular structures surrounded by unit membrane and are found in the cytoplasm It is filled with large number of small granules which contain variety of enzymes , called lysozymes. FUNCTIONS Acts as a form of digestive system for the cell Engulf worn out components of the cellsand exogenous substances eg.bacteria and degrade them . When a cell dies, lysosomal enzymes causes autolysis of the remnant (suicidal bags)

16. CENTROSOMES OR CENTRIOLES These are two short cylinders visible only during cell division Located near the nucleus FUNCTION They are concerned with the movement of the chromosomes during cell division

17. CYTOSKELETON The cytoskeleton is a complex mesh of microtubules, microfilaments and intermediate filaments in the cells of eukaryotes and prokaryotes which are made up of proteins. FUNCTIONS OF CYTOSKELETON Provides  mechanical support  to the cell Keeps  cell organelles separate  from each other Maintains the  cell shape  too. Helps in cell  movement .

18. MICROTUBULES and MICROFILAMENTS Microtubules are long hollow structures on which chromosomes , mitochondria and secretion granules move from one part of the cell to the cell to another . Microfilaments are solid fibers and compromise the contractile protein actin. FUNCTION These are involved in movement of the chromosomes cell movement process that move secretion granules in the cell movement of proteins within the cell membrane