Cell - Focus Dentistry

A cell is the smallest unit that is capable of performing life functions.

Cell, the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed.

Prokaryotic cell	Eukaryotic cell
Lack a nucleus or membrane-bound structures (e.g.bacteria)	Have a nucleus and membrane-bound organelles (e.g.animals plants, fungi)

Mathias J Schleiden (1838) ; a German botanist and Theodore Schwann (1839) ; a British Zoologist proposed cell theory.
All living organisms are composed of cells and product of cells.
All cells arise from pre existing cells through the process of cell division.
The body of living organisms is made up of one or more cells.

Cell has non living outer layer called CELL WALL found only in plant cells.
Below cell wall is CELL MEMBRANE.
CELL MEMBRANE encloses PROTOPLASM.
PROTOPLASM has semi fluid matrix called CYTOPLASM and large membrane bound structure called NUCLEUS.
CYTOPLASM has many membrane bound organelles like Endoplasmic reticulum , Golgi Bodies Mitochondria ,Plastids and vacuoles.
They also have non membrane bound structures called Ribosomes and Centrosomes.
Cytoplasm without Cell organelles are called Cytosol.

Present in all cells, just below the cell wall in plant cells,outermost membrane in animal cells.
Semi-permeable.
Made up of phospholipids, proteins, carbohydrates and Cholesterol.
FUNCTION: It allows outward and inward movement of molecules across it like diffusion, osmosis, active transport, phagocytosis and pinocytosis.

Semi fluid matrix present between cell membrane and nuclear membrane.
It has various living cell inclusions called cell organelles and non living substances called Ergastic substances.

Known as the cell’s “command center,” the nucleus is a large organelle that stores the cell’s DNA (deoxyribonucleic acid).
The nucleus controls all of the cell’s activities, such as growth and metabolism, using the DNA’s genetic information.
Within the nucleus is a smaller structure called the nucleolus, which houses the RNA (ribonucleic acid).
RNA helps convey the DNA’s orders to the rest of the cell and serves as a template for protein synthesis.

Free in cytoplasm	Attached to RER
Makes proteins for use w/in cell.	Makes proteins for export out of cell.

If the proteins from the rough ER require further modification, they are transported to the Golgi apparatus (or Golgi complex).
Like the ER, the Golgi apparatus is composed of folded membranes.
It searches the protein’s amino acid sequences for specialized “codes” and modifies them accordingly.
These processed proteins are then stored in the Golgi or packed in vesicles to be shipped elsewhere in the cell.

Spherical or rod shaped.
It has two membranes, outer membrane is smooth, inner membrane produces finger like infoldings called Cristae.
Inner membrane also has stalked particles called Racker’s particles or Oxysomes.
The mitochondria is filled with granular mitochondrial matrix.
Matrix has circular mitochondrial DNA, RNA, 70sRibosomes, proteins, Enzymes and lipids
FUNCTION : Synthesizes and stores energy rich molecules ATP(Adenosine Tri phosphate) during aerobic respiration

The endoplasmic reticulum (ER) is a membranous organelle that shares part of its membrane with that of the nucleus.
Some portions of the ER, known as the rough ER, are studded with ribosomes and are involved with protein manufacture.
The rest of the organelle is referred to as the smooth ER and serves to produce vital lipids (fats).

Cleanup crews OR the suicidal bag of cell.
Lysosome – organelle that contains chemicals & enzymes necessary for digesting certain materials in the cell.
Single membrane bound vesicles filled with hydrolytic enzymes found only in animal cells.
Produced from golgi complex.
4 Types - Primary, secondary, residual & auto lysosomes
FUNCTION: Intracellular digestion, Destroy old and non functional cells, Recycles worn out cell