Answer:
3rd generation = 2 Hybrid DNA molecules + 6 Light DNA
In Percentage 2÷8 × 100 = 25%
25% of the DNA are hybrid
Explanation:
Semi conservative model proposed by Watson and Crick states that one strand of the DNA comes from parent DNA which act as a template for the other newly formed strand.
First generation:
If cells containing 15 N DNA are transferred to a medium with only 14 N then in initial first generation two parent strands becomes separated and act as template for newly synthesized strands. this means that in first generation both DNA molecules are hybrid, one strand of 15 N DNA and other strand of 14 N DNA
Ist generation = 2 Hybrid DNA molecules
Second generation:
In Second generation these two hybrid molecules become unzip. Two strands are 15N and two strands are 14N. All these 4 strands act as template and 4 new strands are synthesized. The molecules of Hybrid DNA is still 2 with 2 molecules of Light DNA.
2nd generation = 2 Hybrid DNA molecules + 2 Light DNA
Third generation:
In Third generation these two hybrid molecules and two light DNA molecules become unzip. Two strands are of 15N and six strands are of 14N. All these 8 strands act as template and 8 new strands are synthesized. The molecules of Hybrid DNA is still 2 with 6 molecules of Light DNA.
3rd generation = 2 Hybrid DNA molecules + 6 Light DNA
In Percentage 2÷8 × 100 = 25%
25% of the DNA are hybrid
