A mixture containing DNA fragments a, b, c and d, with molecular weights of a+b = c, a>b and d>c, was subjected to agarose gel electrophoresis. The positions of these fragments from cathode to anode sides of the gel would be

In agarose gel electrophoresis, DNA fragments are separated based on their size. Smaller fragments migrate faster through the gel than larger fragments. The anode is positively charged and the cathode is negatively charged. Since DNA is negatively charged, it migrates towards the anode.

Given that:

• a + b = c
• a > b
• d > c

From these relationships, we can deduce the order of molecular weights:

1. d > c: Fragment d has the highest molecular weight.
2. c = a + b: Fragment c has a molecular weight equal to the sum of a and b.
3. a > b: Fragment a has a higher molecular weight than fragment b.

Therefore, the order of fragments from smallest to largest molecular weight is b, a, c, d. In electrophoresis, smaller fragments migrate faster towards the anode. Thus, the order of fragments from cathode to anode will be b, a, c, d.