Question

structural features of cell wall and plasma membrane

Answer 1

All cells are surrounded by a plasma membrane. The membrane is composed of a phospholipid bilayer arranged back-to-back. The membrane is also covered in places with cholesterol molecules and proteins. The plasma membrane is selectively permeable and regulates which molecules are allowed to enter and exit the cell.

Answer 2

Hello!!

_______________________________

Cell Wall:

➡️ The cells of bacteria, fungi algae and plants have an additional non-living rigid structure called the "cell wall" that surrounds the plasma membrane.

Functions of Cell Wall:

➡️ It maintains shape of the cells.

➡️ it protects the cell from mechanical injury.

➡️ It wards off the attacks of pathogens like viruses , bacteria and fungi.

➡️ It allows the material to pass in and out of the cell.

➡️ It helps in cell-to-cell interaction and provides Barrier to undesirable macromolecules.

Cell Membrane:

➡️ Plasma membrane is an absolute requirement for all living organisms as it is responsible for the relationship of a cell with the outside world.

➡️ Cell membrane is composed of lipids that are arranged in a bilayer.

➡️ In human beings, the membrane of the erythrocytes has approximately 52% protein and 40% lipids.

Functions of Cell Membrane:

➡️ The fluid nature of the membrane is important from the point of view of functions like cell growth, formation of intercellular junctions, secretion, endocytosis, cell division etc.

➡️ Plasma membrane allows the transport of the molecules across it.

➡️ The membrane is selectively permeable to some molecules present on either side of it.

➡️ The passage of substances across cell membrane occurs by various methods such as passive transport and active transport.

_______________________________

Thanks!!