Amino acids contain amino (–NH₂) and carboxyl (–COOH) functional groups. Depending upon the relative position of amino group with respect to carboxyl group, the amino acids can be classified as α, β, γ, δ and so on. Only α-amino acids are obtained on hydrolysis of proteins. They may contain other functional groups also. All α-amino acids have trivial names, which usually reflect the property of that compound or its source. Glycine is so named since it has sweet taste (in Greek glykos means sweet) and tyrosine was first obtained from cheese (in Greek, tyros means cheese.) Amino acids are generally represented by a three letter symbol, sometimes one letter symbol is also used. Amino acids are classified as acidic, basic or neutral depending upon the relative number of amino and carboxyl groups in their molecule. Equal number of amino and carboxyl groups makes it neutral; more number of amino than carboxyl groups makes it basic and more carboxyl groups as compared to amino groups makes it acidic. The amino acids, which can be synthesized in the body, are known as nonessential amino acids. On the other hand, those which cannot be synthesized in the body and must be obtained through diet, are known as essential amino acids.

Identify the amino acid with the formula HOOC-CH₂-CH₂-CH(NH₂)-COOH.

Glutamic acid

The correct answer is option 1. Glutamic acid.

The chemical formula of glutamic acid is \(HOOC-CH_2-CH_2-CH(NH_2)-COOH\).

Let us dissect each segment for better understanding:

\(HOOC\): This represents the carboxylic acid functional group. It consists of a carbon atom double-bonded to an oxygen atom (carbonyl group) and a hydroxyl group \((-OH)\) attached to the same carbon. This group gives glutamic acid its acidic properties.

\(-CH2-CH2-\) : These represent two methylene groups \((CH_2)\), simple hydrocarbon chains with two hydrogen atoms attached to each carbon.

\(-CH(NH_2)-\) : This central component features a carbon atom bonded to an amine group \((NH_2)\). This is the characteristic element of an amino acid, making it an essential building block of proteins. The amine group contributes to the basic nature of glutamic acid.

\(-COOH\): This final segment reiterates the presence of the carboxylic acid group, further emphasizing its functional role.

Matching the Formula:

When comparing the given formula \(HOOC-CH_2-CH_2-CH(NH_2)-COOH\) to the options provided, we find an exact match with glutamic acid.

Aspartic acid, while seemingly similar, lacks one methylene group \((-CH_2-)\) in its structure, resulting in a shorter side chain.

Glutamine and Arginine both possess significantly different side chains with distinct functional groups (\(NHCOCH_3\) and guanidinium, respectively), deviating from the provided formula.

Therefore, based on the presence and arrangement of the functional groups and hydrocarbon chains, the formula unequivocally identifies glutamic acid as the correct answer.

Additional Information:

Glutamic acid is a non-essential amino acid, meaning the body can synthesize it under normal conditions. It plays a crucial role in several biological processes, including:

Neurotransmission: Glutamate acts as an excitatory neurotransmitter in the brain, influencing learning, memory, and cognition.

Energy metabolism: Glutamate contributes to the Krebs cycle, a central pathway for energy production in cells.

Protein synthesis: Glutamic acid serves as a building block for protein synthesis, essential for various cellular functions.

Understanding the chemical structure and properties of amino acids like glutamic acid is vital for comprehending fundamental biochemical processes and their implications in human health.