डी.एन.ए. रेणू वेगळे करण्यासाठी अगारोज जेल्स वापरतात कारण अगारोज _____

The correct answer is Option B (is a highly porous material).

Key Points:
• Agarose Gel Electrophoresis Principles:
• Agarose is a natural linear polysaccharide polymer extracted from red seaweed (*Rhodophyta*).
• Molecular Sieving Mechanism:
• Upon cooling, agarose forms a three-dimensional polymer network held by hydrogen bonds, creating a highly porous molecular sieve.
• Because DNA molecules carry uniform negative charges due to their phosphate backbones (PO₄³-), they migrate toward the positive anode under an electric field.
• The microscopic matrix pores exert a size-dependent friction: smaller DNA fragments pass through the pores quickly, while larger fragments are impeded, effectively fractionating DNA strictly by molecular size.
• Hence, agarose is chosen because it is a highly porous material (Option 2).
• Key Takeaway: Agarose forms a porous molecular sieving matrix that separates negatively charged DNA fragments by size during electrophoresis.