The `pH` value of the solution in which a particular amino acid does not migrate under the influence of electric field is called the:

Options

A. Neutralisation point
B. End point
C. lsoelectric point
D. All of these

Answer

To solve the question, "The pH value of the solution in which a particular amino acid does not migrate under the influence of an electric field is called the:", we will follow these steps:

### Step 1: Understand the Concept of Amino Acids and Charge
Amino acids can exist in different charged forms depending on the pH of the solution. At low pH (acidic conditions), amino acids tend to be positively charged, while at high pH (basic conditions), they can become negatively charged.

**Hint:** Remember that the charge of an amino acid can change with pH.

### Step 2: Define the Isoelectric Point (pI)
The isoelectric point (pI) is the specific pH at which an amino acid exists in a neutral form, known as the zwitterion. At this point, the amino acid has both positive and negative charges that balance each other out, resulting in no net charge.

**Hint:** The isoelectric point is where the amino acid is neutral and does not migrate in an electric field.

### Step 3: Identify the Zwitterion Form
At the isoelectric point, the amino acid exists as a zwitterion, which means it has both a positive charge (on the amino group) and a negative charge (on the carboxyl group). This form is stable and does not migrate towards either electrode when an electric field is applied.

**Hint:** The zwitterion form is crucial for understanding why the amino acid does not migrate.

### Step 4: Conclusion
Since the question asks for the pH value at which the amino acid does not migrate under the influence of an electric field, the correct answer is the isoelectric point.

**Final Answer:** The pH value of the solution in which a particular amino acid does not migrate under the influence of an electric field is called the **isoelectric point**.