Question

All DNA polymerases lay down nucleotides in a ____________ direction and move along the template in a _________ direction

- 5' → 3', 3'→ 5'

- 5'→ 3', 5' → 3'

- 3' → 5', 3' → 5'

- 5→ 3, 3 → 5

- 3' → 5', 5' → 3'

Answer 1

DNA polymerases add nucleotides in the 5'→ 3' direction while reading the template strand in the 3'→ 5' direction. The leading strand is synthesized continuously towards the replication fork, while the lagging strand is synthesized in Okazaki fragments away from the fork.

Step-by-step explanation:

All DNA polymerases lay down nucleotides in a 5'→ 3' direction and move along the template in a 3'→ 5' direction. This is because DNA polymerases can only add nucleotides to the 3' end of a growing DNA strand, thus extending the strand in the 5'→ 3' direction. The enzyme reads the template strand in the opposite 3'→ 5' direction to ensure the correct base pairing during DNA replication. The leading strand is synthesized towards the replication fork, allowing continuous replication in the same direction as the fork progression. In contrast, the lagging strand is synthesized away from the replication fork in short stretches known as Okazaki fragments, which requires a primer to start each new fragment.