Question

Which strand forms the inner circle in rolling circle replication?

1) Outer strand
2) Inner strand
3) Both strands
4) None of the above

Answer 1

In rolling circle replication, the inner strand forms the inner circle and serves as the template for synthesis. The outer strand is displaced and does not make up the inner circle. The answer to the student's question is: 2) Inner strand.

Step-by-step explanation:

In rolling circle replication, the process begins with a nick on one of the strands of the circular DNA molecule. The DNA polymerase then uses the un-nicked strand, often referred to as the template strand, to synthesize a new strand. During this process, the nicked strand is displaced and can be described as the outer strand due to its displacement away from the circular path of replication. Therefore, it is the inner strand, which serves as the template for the DNA polymerase, that forms the inner circle during rolling circle replication.

In this replication method, enzymes such as DNA polymerase and RNA primase play crucial roles. New bases are added to the ever-growing strand, and the enzymatic activity of these enzymes allows for the synthesis of a single new copy of the DNA molecule. Thus, the answer to the student's question is 2) Inner strand, as it is the template for replication and forms the inner circle during this replication process.