The R group or side chain of the amino acid serine is -CH₂-OH. The R group or side chain of the amino acid alanine is -CH₃. Where would you expect to find these amino acids in a globular protein in aqueous solution?
A)Serine would be in the interior, and alanine would be on the exterior of the globular protein.
B)Alanine would be in the interior, and serine would be on the exterior of the globular protein.
C)Both serine and alanine would be in the interior of the globular protein.
D)Both serine and alanine would be on the exterior of the globular protein.
E)Both serine and alanine would be in the interior and on the exterior of the globular protein.

Question

Quizplus · Accepted Answer

Alanine has a non-polar side chain (-CH₃), which would be more likely to be found in the hydrophobic interior of the globular protein. Serine has a polar side chain (-CH₂-OH), which would be more likely to be found on the surface or exterior of the protein where it can interact with water molecules. Therefore, alanine would be expected in the interior, and serine would be expected on the exterior of the globular protein.

The R Group or Side Chain of the Amino Acid