Question

Briefly explain which components of the plasma membrane allow it to be selectively permeable. Specify how each of the components selected contribute to the selective permeability of the membrane.

Answer 1

• Hydrophobic center to a cell membrane ( also known as phospholipid bilayer) gives the membrane selective permeability.
• Cell membranes are primarily composed of lipid molecules called phospholipid.These membrane also contain protein.
• Each phospholipid has hydrophilic head that attract water and each phospholipid has 2 hydrophobic fatty acid tails that are repelled by water.
• When many phospholipids are put in a watery solution , they spontaneously form spheres called liposomes , that point all water loving heads towards the water and shield all water fearing tails from it.
• As a result of hydrophobic center of the membrane is that molecule that dissolves in water are not capable of passing through the membrane.Charged atoms and polar molecules such as glucose are repelled by the hydrophobic center of the membrane.
• On the other hand , hydrophobic molecules such as lipids can pass through the membrane.