Given below is the schematic representation of the process of electrophoresis. Identify the alphabets representing the: Anode end, and Lightest/Smallest DNA in matrix.
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Remember the phrase "Run towards the Red Anode." Since DNA is negative, the smallest fragments will travel fastest and be found closest to the positive anode end (S), while heavy fragments lag behind near the loading wells.
Step 1: Understanding the Question:
The question provides a diagram of an agarose gel electrophoresis plate showing sample loading wells and separated bands. We need to identify which letter corresponds to the positive electrode terminal (Anode end) and which letter points to the smallest migrated DNA fragment. Step 2: Key Formula or Approach:
DNA molecules carry a uniform negative charge due to the phosphate groups in their structural backbone. Therefore, when placed in an electric field, they migrate away from the negative cathode terminal toward the positive Anode terminal.
Agarose gel functions as a molecular sieve. Smaller, lighter DNA fragments travel through the pores much faster and farther than larger, heavier fragments. Step 3: Detailed Explanation: (I) Identifying the Anode End: The sample loading wells are labeled as P on the left side near end U. Because DNA is loaded into these wells and moves from left to right toward end S, end U represents the negative cathode and end S represents the positive Anode terminal. Thus, S is the anode end. (II) Identifying the Smallest DNA Fragment: The DNA fragments separate by size along the lane. The bands labeled Q are closest to the wells, meaning they are the largest, heaviest fragments that moved the least. The bands labeled R have migrated the farthest toward the positive terminal S. This indicates that they are the smallest, lightest DNA fragments. Thus, R represents the smallest DNA in the matrix. Step 4: Final Answer:
(I) The Anode end is represented by the letter S.
(II) The lightest/smallest DNA fragment in the matrix is represented by the letter R.
