Question

tell me about cell:structure and function

Answer 1

each organ in the system perform different functions such as digestion, assimilation and absorption. Different organs of a plants perform specific functions.

Answer 2

Every cell is enclosed by a thin covering called the cell membrane, or plasma membrane,or plasmalemma. It can be seen only with electron microscope. It is not visible through the light microscope as its thickness is well below the resolving power of this microscope.

✧Molecular Structure

●Cell membrane is composed of two layers of lipids.
●It contains the continuous layer of proteins on either surface.

●Cell membrane consist of phospholipid bilayer sandwiched b/w two protein layers.

●The lipids and phospholipid molecules are a set at right angles to the surface.
●Oligosaccharide molecules associated with the exoplasmic surface of cell membrane add to its asymmetry.
●The biologocal membrane are semipermeable and allow passage of selectively substances by (i) physical processes (diffusion, osmosis) and (ii) biological processes (transport by membrane proteins and internalization of macromolecules, fluid droplets and large particles).

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Functions of cell membrane

1-It maintains the individuality and form of the cell.
2-It keeps the semifluid cell contents in place and distinct from the environmental materials.
3-It protects the cell from injury.
4-It regulates the flow of materials into and out of the cell.
5-It forms organelles within the cytoplasm.
6-Its junctions keep the cells together.
7-Its infolds help in the intake of materials by endocytosis.
8-It outfolds increase the surface area for absorption of nutrients.
9-Its receptor molecules permit the flow of information into the cell.
10-It permit exit of secretions and wastes by exocytosis.