The main components of the plasma membrane contain hydrophobic and hydrophilic regions that give the membrane selective permeability. Which of the following is the main component that creates the hydrophobic and hydrophilic regions? (3 points)
a. Cholesterol molecules creating membrane fluidity
b. Carbohydrates for cell recognition
c. Glycolipids containing hydrophobic lipid portion
d. Phospholipids containing hydrophobic fatty acids tails

The main components that creates the hydrophobic and hydrophilic regions of the plasma membrane are phospholipids containing hydrophobic fatty acids tails.

Explanation:

Phospholipids are the main component of the cell membrane —lipid bilayer— and responsible for its selective permeability.  Each phospholipid is composed of one glycerol molecule, which forms the head, and two fatty acid tails, plus one phosphate molecule.

In the lipid bilayer, the phospholipid heads are oriented towards the surface, while the tails are located inside, allowing interaction with both polar and apolar molecules.

The hydrophilic regions of the membranes are in contact with the liquids of the extracellular and intracellular spaces, while the hydrophobic region is inside the membrane, limiting the passage of polar molecules or ions.

The other options are not correct because:

    a. Cholesterol molecules are part of the membrane, but are not responsible for the hydrophobic and hydrophilic regions.

    b. Carbohydrates for cell recognition do not determine membrane permeability.

    c. Glycolipids, like integral proteins, are part of the membrane, but do not determine the polarity of the regions.