Question

Which of these amino acids is most likely to be found at the periphery (edge) of a membrane bilayer in a transmembrane protein?

a) Glycine
b) Proline
c) Leucine
d) Serine

Answer 1

The amino acid serine is most likely to be found at the periphery of a membrane bilayer in a transmembrane protein because its polar side chain allows it to interact with the hydrophilic environment outside the cell membrane.

Step-by-step explanation:

The student asked which of these amino acids is most likely to be found at the periphery (edge) of a membrane bilayer in a transmembrane protein. Transmembrane proteins interact with the polar environment on the outside of the cellular membrane, thus the amino acids on their periphery tend to be polar or charged to facilitate this interaction. Among the options provided (glycine, proline, leucine, serine), serine is the amino acid with a polar side chain that is able to form hydrogen bonds with water. Therefore, serine is most likely to be found at the edge of a membrane bilayer.

Properties of amino acids dictate their position within proteins. As serine contains a hydroxyl group, it is polar and compatible with the hydrophilic environment outside the membrane, making it ideal for the periphery of a transmembrane protein. Unlike non-polar amino acids like leucine, polar amino acids such as serine play a crucial role in interactions with the aqueous environment, thus explaining their external localization on membrane proteins.

Answer 2

The amino acids which is most likely to be found at the periphery (edge) of a membrane bilayer in a transmembrane protein is a) Glycine

Step-by-step explanation:

Glycine is most likely to be found at the periphery (edge) of a membrane bilayer in a transmembrane protein. Its small size and flexibility allow it to be accommodated in the confined space near the membrane-water interface.

Proline, leucine, and serine, due to their specific structural characteristics, are more commonly found within the hydrophobic core of the membrane.

Therefore, option a) Glycine is correct answer.