Cell and Tissue
Cell
– cell is the smallest and functional unit of the body
-it also known as building blocks of the life
-The cell word derived from Latin word Calla which means ‘small room’
-Smallest cell of the human body – Sperm
-Largest cell of the human body- Ovum
-The smallest living cell on the earth – micro plasma
-The largest living cell on the earth – Egg cell of ostrich
-Father of cell – Robert Hook (1665) [discovered dead cell in cork cell]
-Anton van Leeuwenhoek (1674) [Discovered live cell in algae of water]
-the human body develops from a single cell called
-which is result from the fusion of ovum and sperm
A Cell consist of a –
- Plasma membrane
- Nucleus (organelles)
- Cytoplasm
CELL MEMBRANE
-It is also known as plasma membrane or cytoplasmic membrane.
-it a semipermeable or selective membrane in nature
-cell membrane is the protective sheath covering the cytoplasm
-it is compose of two layers of phospholipid in which these two layers of phospholipid protein molecules and sugar molecules embedded in
-the plasma membrane is formed by protein, lipid and carbohydrate
-the phospholipid molecules have a head which is electrically charged and hydrophilic in nature (water loving)
Protein – 50%
Lipid- 40%
Carbohydrate – 10%
-And a tail which has no charged and it hydrophobic in nature means water hate
-the phospholipid bilayer is arranged like a sandwich
#Function of cell membrane
- Carbohydrate molecules attached to outside of the cell membrane and protein molecules gives the cell its immunological identity
- It can act as specific receptor for hormone and other chemicals messenger
- It involve in transportation between intracellular and extracellular
- Transport of substance from plasma membrane
There are two types of transport
- Passive transport
- Active transport
Passive transport –
– Energy is not required
– It occurs when substance move form an area of higher concentration to lower concertation
Ex. Diffusion & osmosis
Diffusion – diffusion mean transport of gas from a higher concentration to lower constriction
Osmosis – transportation of a solvent (water) through a semi-permeable membrane from higher concentration to lower concentration
Active transport –
Transport of substances from lower to higher concertation using energy from the cell
Ex. Endocytosis & exocytosis
Endocytosis – it is process by which cell absorb external material by engulfing it is sub divided into – phagocytosis (खाना) & phagocytosis (पीना)
Exocytosis – it is a process for moving large molecule out of the cell. Ex. – Na⁺, K⁺, pump which exchange in sodium? Potassium ion across the cell membrane
