The pH at which an amino acid carries no net charge is called it's

Options

A. isoelectric point
B. inversion point
C. neutralisation point
D. triple point

Answer

To answer the question, "The pH at which an amino acid carries no net charge is called its ___", we can follow these steps:

### Step 1: Understanding the Structure of Amino Acids
Amino acids are organic compounds that contain both an amine group (–NH2) and a carboxylic acid group (–COOH), along with a side chain (R group) that varies between different amino acids. The presence of these functional groups is crucial for understanding their behavior in different pH environments.

**Hint:** Recall the basic structure of amino acids, focusing on the amine and carboxylic acid groups.

### Step 2: Defining Net Charge
The net charge of an amino acid depends on the pH of the solution. At different pH levels, the amine group can be protonated (–NH3+) or deprotonated (–NH2), and the carboxylic acid group can be protonated (–COOH) or deprotonated (–COO−). The overall charge of the amino acid will vary based on the ionization of these groups.

**Hint:** Consider how the ionization of the amine and carboxylic acid groups changes with pH.

### Step 3: Identifying the Isoelectric Point
The isoelectric point (pI) is the specific pH at which the amino acid has no net charge. At this pH, the positive and negative charges balance each other out, resulting in a neutral overall charge. This point is crucial for understanding the behavior of amino acids in biological systems.

**Hint:** Remember that the isoelectric point is where the amino acid is neutral, meaning the positive and negative charges are equal.

### Step 4: Conclusion
Based on the information above, the pH at which an amino acid carries no net charge is called its **isoelectric point (pI)**.

**Final Answer:** The pH at which an amino acid carries no net charge is called its **isoelectric point**.