Question

A phospholipid molecule is amphipathic and produces two layers coming in contact with $H_{2}O$. The head of phospholipid molecule is

• A. At an angle of ${40}^o$
• B. At the outer surface
• C. On the inner side
• D. Embedded in protein molecules

Answer 1

Answer: (B)

At the outer surface

The lipid molecules are amphipathic, i.e., they possess both hydrophilic (Watter loving) and non polar hydrophobic (water repelling) ends. The hydrophilic region is in the form of a head occurring at outer surface while the hydrophobic part contains two tails of fatty acids. Hydrophobic tails usually occur towards the centre of the membrane. If results in the membrane. It results in the formation of a lipid bilayer. Most common lipid in the bilayer is phospholipid. So, the correct answer is 'at the outer surface'.