Consider the above diagram of DNA molecules All molecules ar

Consider the above diagram of DNA molecules. All molecules are ~ 1000b long. Which molecule(s) could be a substrate for primase? C and D A, C and D B only A only A and D

Solution

\'B\' only is the correct answer.

Explanation: Primase attaches to 3\' end of DNA template; so that RNA synthesis occurs in 5\' to 3\' direction. In option A Primase will not be able to attach to 3\' end of template because sticky end is there at there at 5\' template end. Please note that in options A, C and D the DNA strands are not consistent. RNA polymerase continues synthesis in even and consistent strands; these three strands are not even and consistent.