The simplified diagram of rhodopsin shows the protein embedded in the phospholipid bilayer of the membrane. Portions of the protein extend into the intracellular and extracellular spaces.

Question

A general bullet-shaped protein embedding in a phospholipid bilayer membrane. The protein contains coiling ribbons inside it. These ribbons coil most tightly in the center and then spread out in the head of the bullet. In the tightly coiled section there is a separate, bunched chain of small spheroids.

Which characteristics best describe the side chains in the part of the protein in contact with the phospholipid tails of the membrane?

Non-polar; hydrophobic
Polar; hydrophilic
Charged – basic; hydrophilic
Charged – acidic; hydrophilic

Answer 1

The side chains in the part of the protein that is in contact with the phospholipid tails of the membrane are best described as non-polar; hydrophobic.

This is because the hydrophobic tails of the phospholipids repel water and are predominantly composed of non-polar fatty acid chains. Consequently, proteins that interact with these phospholipid tails typically have non-polar (hydrophobic) amino acid side chains that help to stabilize the protein within the membrane by avoiding interactions with the aqueous environment.