The cell membrane is a semi-permeable membrane that surrounds the cytoplasm of all cell types. It is composed mainly of phospholipids organized into a fluid mosaic structure along with embedded proteins and carbohydrates. The phospholipids are arranged as a bilayer with hydrophilic heads facing outwards and hydrophobic tails in the middle. Membrane proteins can be integral, embedded in the bilayer, or peripheral, attached to the surface. They perform functions like transport, signaling, and structural support.

1. CELL MEMBRANE

2. Cell Membrane (Plasma Membrane)
Semi-permeable membrane that isolates cytoplasm from the surrounding
environment
Found in all cell types
It is alive
Selectively-permeable to materials

3. Main component of cell membrane is a type of lipid, called
phospholipid
It includes speical proteins and carbohydrates embedded on it .

4. Fluid mosaic cell structure is well-recognized cell membrane model,
discovered by Singer and Nicholson in 1972.
The term ‘fluid’ refers fluidity of the membrane and ‘mosaic’ refers to
different organic compounds (lipid, protein and carbohydrates) which
cell membrane has

5. Cell membrane is made up of phospholipids.
A phospholipid molecule has two parts: hydrophilic head and
hydrophobic tail
Hydrophilic head is composed of glycerol and phosphate and
attracts water
Hydrophobic tail is composed of fatty acid chains and repels water.
This movements make cell membrane alive

6. There are two types of proteins on the cell membrane: integral and
peripheral
If the proteins are embedded into the phospholipid bilayer, they
are integral proteins
They are usually involved in transporting substances across the cell
membrane
If they are only found on the surface of the cell mebrane, they are
peripheral proteins.
They are involved in maintaining the cell’ shape or motility.

9. Membrane proteins may have different roles
Channel proteins allow movements of specific molecules across cell
membrane
Receptor proteins detect hormones arriving cells
Electron carriers allow electrons to pass across the membrane

10. Glycoproteins: function in the cell to cell recognition, selectively permeability of
cell membrane, receptors for chemical signals and recognition of hormones.
Glycolipids: They are called cell markers
or antigens and can be recognized by the
cells of the immune systems as self (of
the organism) or non-self (of cells
belonging to other organisms).
Cholesterol: maintains the integrity and
the fluidity of the cell membrane, also
gives the extra support.