Question

The direction of DNA synthesis by DNA polymerases is sometimes 5′ to 3′ and sometimes 3′ to 5′, depending on whether the organism is a prokaryote or a eukaryote.

Options:
A. False
B. True

Answer 1

DNA polymerase synthesizes DNA in the 5' to 3' direction in both prokaryotic and eukaryotic cells, making the statement False. Both strands, leading and lagging, are synthesized simultaneously, with Okazaki fragments forming on the lagging strand.

Step-by-step explanation:

The correct answer to the question is False. DNA polymerase synthesizes DNA only in the 5' to 3' direction, regardless of whether the organism is a prokaryote or a eukaryote. This is because DNA polymerases can only add nucleotides to the 3' end of a DNA strand. The leading strand is synthesized continuously in the direction of the replication fork, while the lagging strand is synthesized discontinuously in short stretches called Okazaki fragments that are later joined together.

In both prokaryotic and eukaryotic cells, the direction of DNA synthesis remains the same. The anti-parallel nature of the DNA double helix means that while one strand can be synthesized continuously (the leading strand), the other strand (the lagging strand) must be synthesized in fragments as the replication fork opens up more of the DNA helix.