Question: 153: Given below are two statements:
Statement I :
Amino acids have a property of ionizable nature of -\mathrm{NH}_{2} and -COOH groups, hence have different structures at different pH .
Statement II :
Amino acids can exist as Zwitterionic form at acidic and basic pH .
In the light of the above statements, choose the most appropriate answer from the options given below:
(1) Both Statement I and Statement II are correct
(2) Both Statement I and Statement II are Incorrect
(3) Statement I is correct but Statement II is incorrect
(4) Statement I is incorrect but Statement II is correct
Answer: Option (1)
Explanation:
Amino acids contain both an amino group and a carboxyl group, which are ionizable in nature.
The amino group can accept a proton and the carboxyl group can donate a proton,
so the ionic form of an amino acid depends on the pH of the surrounding medium.
At different pH values, amino acids exist in different ionic forms such as
cationic, zwitterionic, or anionic forms.
Amino acids exist predominantly in the zwitterionic form, having both positive and negative charges, due to internal proton transfer.
This zwitterionic nature is observed depending on the pH conditions and is an important characteristic of amino acids.
Hence, both Statement I and Statement II are correct.