Arrange the following DNA fragments A, B, C, D separated after Gel Electrophoresis in increasing order of number of their base pairs
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In gel electrophoresis, remember the simple rule: "Small runs fast." The fragments at the bottom of the gel are the smallest, and those at the top are the largest. Always check if the question asks for increasing or decreasing order of size.
Step 1: Understanding the Concept:
Agarose gel electrophoresis is a technique used to separate macromolecules like DNA based on their size.
DNA has a uniformly negative charge, so when an electric field is applied, it migrates from the negative electrode (at the top, by the wells) towards the positive electrode (at the bottom).
The agarose gel acts as a sieve. Smaller DNA fragments move faster and farther through the gel than larger fragments. Step 2: Detailed Explanation:
The starting points are the "Wells" at the top.
The distance traveled is inversely proportional to the size of the DNA fragment.
Observing the positions on the gel:
Fragment A has traveled the farthest distance, making it the smallest.
Fragment D has traveled the next farthest distance.
Fragment C has traveled less distance than D.
Fragment B has traveled the shortest distance, making it the largest.
The question asks for the order of increasing number of base pairs, which means from smallest to largest.
Step 3: Final Answer:
The correct order from smallest to largest is A, D, C, B.
