Final answer:
b) Serine The amino acid with an R group outlined as CH₂ - OH is serine. Its polar hydrophilic side chain distinguishes it from other amino acids like alanine, threonine, and cysteine.
Step-by-step explanation:
The amino acid that has a side chain (R group) of CH₂ - OH is serine. The R groups define the chemical nature of amino acids, making them distinct from each other.
For example, alanine is characterized by a simple methyl group (-CH₃), making it nonpolar, whereas serine, with its hydroxymethyl group (-CH₂OH), is polar and therefore hydrophilic.
The amino acid threonine also has a similar polar side chain, but with an additional methyl group, making it structurally different from serine.
On the other hand, cysteine contains a thiol group (-SH) and is known for forming disulfide bonds that can affect protein structure. Given the side chain mentioned (CH₂ - OH), the correct classification of the amino acid is serine, option (b).
The amino acid with the chemical structure shown, with an R group outlined by a red box (CH₂-OH), can be classified as b) Serine.
Serine is a polar amino acid with a hydrophilic side chain that contains a hydroxyl group, represented by -OH. It is one of the 20 common amino acids found in proteins.