Join thousands of students who trust us to help them ace their exams!Watch the first video
Multiple Choice
Why is there a problem replicating the ends of linear DNA during DNA replication?
A
The DNA polymerase cannot add nucleotides to the 5' end of the DNA strand.
B
The DNA polymerase cannot add nucleotides to the 3' end of the DNA strand.
C
The DNA polymerase can only replicate circular DNA molecules.
D
The DNA polymerase cannot fully replicate the 5' ends of the lagging strand.
Verified step by step guidance
1
Understand the structure of DNA: DNA is a double-stranded molecule with each strand having a directionality, characterized by a 5' end and a 3' end.
Learn about DNA replication: DNA replication involves the synthesis of a new strand complementary to the template strand, and this process is facilitated by the enzyme DNA polymerase.
Recognize the role of DNA polymerase: DNA polymerase can only add nucleotides to the 3' end of a growing DNA strand, which means it requires a primer to start synthesis and cannot initiate replication on its own.
Identify the issue with linear DNA replication: During replication of linear DNA, the lagging strand is synthesized in short fragments called Okazaki fragments, which are later joined together. However, the very end of the lagging strand cannot be fully replicated because there is no upstream 3' end available for DNA polymerase to extend from.
Understand the consequence: This inability to replicate the very end of the lagging strand results in the progressive shortening of linear DNA molecules with each round of replication, which is why mechanisms like telomerase are important for maintaining chromosome integrity.