KCET 2016 Biology Solved Paper

→ After one generation (after 20 min in which E. coli divides),all DNA molecules would be 15N–14N hybrids. Their density would be halfway between that expected for totally heavy and totally light DNA
→ After the second generation (40 min), the newly synthesized strands would continue to contain only light isotopes as they are now growing on 14NH4‌Cl medium. Two types of bands would appear in the gradients— those containing 15N–14N hybrids and those containing only 14N.