Question

The result of an electrophoretic separation of a mixture of amino acids X, Y and Z at pH = 5.0 is represented as (Given the isoelectric points of X, Y and Z are 9.87, 3.22 and 5.43, respectively) 

• A. A
• B. B
• C. C
• D. D

Hint:

Remember: pH<pI → positive; pH>pI → negative; pH = pI → no movement in electrophoresis.

Answer 1

The Correct Option is A

Step 1: Understanding charges at pH relative to pI.
If pH<pI → amino acid is positively charged (moves toward cathode, i.e., negative electrode).
If pH>pI → amino acid is negatively charged (moves toward anode, i.e., positive electrode).
At pH = 5:
X: pI = 9.87 → pH<pI → positive charge → moves to cathode (right).
Y: pI = 3.22 → pH>pI → negative charge → moves to anode (left).
Z: pI = 5.43 → pH ≈ pI → almost neutral → stays near center.
Step 2: Interpreting diagram positions.
Left = negative amino acid → Y.
Center = neutral amino acid → Z.
Right = positive amino acid → X.
Step 3: Conclusion.
The correct electrophoretic pattern is Y (left), X (right), Z (middle), matching option (C).