Question

What is the structure of L-glyceraldehyde?

Answer 1

Hint: L-glyceraldehyde belongs to the L-series of the amino acids and is a naturally occurring amino acid and in this the -OH group is occurring on the left side and with the $\text{-C}{{\text{H}}_{2}}-\text{OH}$ group occupying the terminal position. Identify the structure.

Complete step by step answer:
Amino acids are the organic compounds containing both the amino group and carboxylic group in their molecules. They are represented by the general formula as:

Here, -C- is called as alpha carbon because the carbon atom attached next to the carboxylic group is called as alpha carbon and the amino acid is known as the alpha amino acid.
R is the side chain and is different for different amino acids.
-COOH is the carboxylic group.
$-\text{N}{{\text{H}}_{2}}$ is the amino group.
In the amino acid , the acidic properties are due to the $-\text{NH}_{3}^{+}$group and the basic properties are due to the $\text{-CO}{{\text{O}}^{-}}$.
With the exception of glycine, all the other alpha amino acids have chiral carbon atom i.e. the carbon which consists of four different groups attached to it and they have two optically active isomers as:

All the naturally amino acids belong to the L-series which have $-\text{N}{{\text{H}}_{2}}$ group on the left side as the -OH group in L-glyceraldehyde.
The structure of L-glyceraldehyde is as:

Thus, the option(c) is correct.

Note: Amino acids are very essential for the healthy body and human body can synthesize 10 out of 20 amino acids found in proteins and such amino acids are called as the non- essential amino acids and the remaining 10 amino acids are not synthesized in the body and have to take from the diet and these are called as the essential amino acids.