Question

During DNA replication, newly formed DNA is built starting at the ___ end and moving towards the __ end

A) 5' end, 3' end
B) 3' end, 5' end
C) 5' end, 5' end
D) 3' end, 3' end

Answer 1

New DNA is synthesized from the 5' to 3' end, with DNA polymerase adding nucleotides to the 3' end. The leading strand is continuous, while the lagging strand is made of Okazaki fragments.

Step-by-step explanation:

During DNA replication, newly formed DNA is built starting at the 5' end and moving towards the 3' end. Therefore, the correct answer to the question is A) 5' end, 3' end. DNA replication occurs in this direction because DNA polymerase can only add nucleotides to the 3' end of a growing DNA strand, forming new phosphodiester linkages.

The leading strand is synthesized continuously in the direction away from the replication fork, while the lagging strand is synthesized in short pieces known as Okazaki fragments, which are later joined together.