Question

Assume that a single layer of phospholipids coat the water in a beaker. which part of the phospholipid molecule will face the air?
a.the phosphate groups
b.the hydrocarbon tails
c.the phospholipids would dissolve and not form a membrane coat
d.both heads and tails as the molecules are amphipathic and will lie sideways

Answer 1

Answer: The correct answer is-

b.the hydrocarbon tails.

A phospholipid molecule comprises of a head group (that contains polar phosphate molecule) that is hydrophilic ( water attracting groups due to formation of hydrogen bonding or ionic bonds with water molecules) and two tails of fatty acid ( which are hydrophobic that is water repelling groups).

In this question, a single layer of phospholipid coats the water in a beaker. This means that head group of this layer is in contact of water ( present in the beaker) and the two fatty acid tails of hydrocarbon ( that are water repelling) are facing air.

Thus, option b) is the right answer.

Answer 2

The part of the phospholipid molecule that will face the water, as it is labelled to be hydrophilic would be the polar phosphate group. The correct response would be A.