CHEMISTRY The two amino acids having R groups with a negative net charge at pH 7.0 are Cysteine and methionine Aspartate and glutamate Proline and valine Arginine and histidine Next This form was created inside of University of Babylon: Report Abuse Google Forms
The Correct Answer and Explanation is:
The correct answer is Aspartate and glutamate.
Explanation:
At physiological pH (around 7.0), amino acids with side chains that can lose a proton (become negatively charged) typically have acidic functional groups. These side chains are known to have a negative net charge at this pH.
- Aspartate (Asp) and glutamate (Glu) are the two amino acids with carboxylate groups (-COO⁻) in their side chains. The carboxyl group can dissociate, losing a proton (H⁺) and thereby carrying a negative charge at physiological pH (pH 7.0). This makes both of these amino acids negatively charged at this pH.
- Cysteine and methionine do not have acidic side chains; cysteine has a thiol group (-SH), which does not ionize significantly at pH 7.0. Methionine has a non-polar side chain and thus does not carry a charge at physiological pH.
- Proline and valine both have non-polar side chains and do not have acidic or basic groups that can gain or lose protons. Therefore, they do not have a net negative charge at pH 7.0.
- Arginine and histidine have positively charged side chains (due to the presence of amino groups in their side chains), so they would have a positive net charge at physiological pH, not a negative one.
Thus, aspartate and glutamate are the amino acids that have R groups with a negative net charge at pH 7.0.
