Question

The Feulgen stain is used for staining

• A. plasma membrane
• B. chromosomes
• C. phospholipids
• D. mitochondria

Answer 1

The Correct Option is B

The Feulgen stain is a specific histochemical staining technique used for detecting DNA in chromosomes. 

Step 1: Understanding Feulgen Stain Mechanism - Feulgen staining is based on the Schiff reagent, which reacts with aldehyde groups produced after DNA hydrolysis with acid. - The resulting reaction produces a reddish-purple coloration, making chromosomes visible under a microscope. - This technique is highly specific for DNA, allowing for quantitative analysis. 

Step 2: Evaluating the Options - Option (A) - Incorrect: The plasma membrane is not specifically stained by Feulgen stain. - Option (B) - Correct: Chromosomes (DNA) are selectively stained by Feulgen stain. - Option (C) - Incorrect: Phospholipids are stained using Sudan stains. - Option (D) - Incorrect: Mitochondria are typically stained with Janus Green B, not Feulgen stain. 

Step 3: Conclusion Since Feulgen stain is used specifically for DNA, which is found in chromosomes, the correct answer is option (B).