Question

If the isoelectric pH of a protein is 3.2 then in a solution of pH 7.4 it will be in:

• A. positively charged form
• B. negatively charged form
• C. Zwitterionic form
• D. form immovable in the electric field

Hint:

pH > pI: negatively charged.
pH < pI: positively charged.
pH = pI: neutral (zwitterionic).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Isoelectric pH (pI) is the pH at which a protein has no net charge.
At pH above pI, the protein is negatively charged.

Step 2: Key Formula or Approach:
No specific formula.
Need to understand the relationship between pH and pI.

Step 3: Detailed Explanation:
pI = 3.2.
Solution pH = 7.4.
Since pH > pI, the protein will lose protons and become negatively charged.
Thus, it will be in negatively charged form.

Step 4: Final Answer:
At pH 7.4, the protein will be in negatively charged form.
Hence, the correct option is (B).