Question

When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). Which two classes of DNA do these different samples represent

Answer 1

Leading strand and Okazaki fragments

Step-by-step explanation:

The two classes of DNA that the different samples represent include the leading strand and the Okazaki fragments.

The large molecules DNA with thousands/millions of nucleotides constitutes the leading strand of the DNA while the short stretches of DNA with just a few thousand nucleotides in light constitute the Okazaki fragments.

This is because, during replication, the leading strands of DNAs are usually synthesized in a continuous manner and end up forming a long, continuous daughter strand while the lagging strands are usually synthesized in short, discontinuous fragments known as the Okazaki fragments.

The continuous/discontinuous replication of the leading/lagging strands of the DNA is due to the characteristics of the enzyme responsible for adding bases to the growing daughter strands. The DNA polymerase enzyme can only add nucleotides in the 5' to ' direction.