why plasma membrane is bilayer of phospholipid
Hello,
A Phospholipid Bilayer
The head “loving " water (hydrophilic) and the tails “hate” water (hydrophobic). Molecules that are hydrophobic can easily pass through the plasma membrane, if they are small enough, because they are water-hating like the interior of the membrane.
Phospholipids, a rranged in a bilayer, make up the basic fabric of the plasma membrane, t hey are well-suited for this role because they are amphipathic, meaning that they have both hydrophilic and hydrophobic regions. Chemical structure of a Phospholipid showing the hydrophilic head and hydrophobic tails.
I hope your question has been answered properly.
All the best!