Question

Identify the correct statement related to amino acids

• A. Nonessential amino acids cannot be synthesized in the body
• B. These are soluble in ether
• C. These are low melting solid substances
• D. In aqueous solution they exist as zwitterion

Hint:

Remember that the zwitterionic form of amino acids is crucial for their properties in aqueous solutions and their biological roles. The simultaneous presence of positive and negative charges within the same molecule influences their solubility, reactivity, and interactions with other molecules.

Answer 1

The Correct Option is D

Amino acids are organic compounds that serve as the building blocks of proteins. They have characteristic features that determine their behavior in different environments. Let's evaluate the given statements:

1. Nonessential amino acids cannot be synthesized in the body: This statement is incorrect. Nonessential amino acids can be synthesized by the human body, which is why they are termed "nonessential."
2. These are soluble in ether: Amino acids are generally not soluble in nonpolar solvents like ether; they are more soluble in polar solvents like water due to the nature of their functional groups.
3. These are low melting solid substances: Amino acids have relatively high melting points due to strong intermolecular forces such as hydrogen bonding. This statement is incorrect in its broad categorization.
4. In aqueous solution they exist as zwitterion: This is the correct statement. Amino acids, when dissolved in water, typically exist in the form of zwitterions, where the amino group is protonated (-NH₃⁺) and the carboxyl group is deprotonated (-COO^-), resulting in a molecule with both positive and negative charges.

Therefore, the correct statement regarding amino acids is: In aqueous solution they exist as zwitterion.