DNA polymerase reads the template strand in which direction?

DNA polymerase reads the template strand in which direction?

• A. 5' to 3'
• B. None
• C. 3' to 5'
• D. Both directions

Answer: (C)

DNA polymerase reads the template strand in the 3' to 5' direction while it synthesizes the new strand in the 5' to 3' direction. This happens because the enzyme adds nucleotides to the 3' end of the growing strand, so it must move along the template from its 3' end toward its 5' end to produce a complementary 5' to 3' growing strand. The antiparallel arrangement of DNA means the template is read 3'→5' to create a new strand that runs 5'→3'. It cannot read the template in the opposite direction during normal replication, and both directions would disrupt the established synthesis chemistry.

DNA polymerase reads the template strand in the 3' to 5' direction while it synthesizes the new strand in the 5' to 3' direction. This happens because the enzyme adds nucleotides to the 3' end of the growing strand, so it must move along the template from its 3' end toward its 5' end to produce a complementary 5' to 3' growing strand. The antiparallel arrangement of DNA means the template is read 3'→5' to create a new strand that runs 5'→3'. It cannot read the template in the opposite direction during normal replication, and both directions would disrupt the established synthesis chemistry.