Which enzyme adds nucleotides during DNA replication?

Which enzyme adds nucleotides during DNA replication?

• A. Helicase
• B. Telomere
• C. Ribosome
• D. DNA polymerase III

Answer: (D)

During DNA replication, nucleotides are added by DNA polymerases to the 3' end of the growing strand, using the parent strand as a template and synthesizing in the 5' to 3' direction. The main enzyme responsible for this synthesis in bacteria is DNA polymerase III, which carries out the bulk of the DNA elongation on both the leading and lagging strands (with primers provided by primase). Helicase, by contrast, unwinds the double helix but does not add nucleotides. The term telomere refers to chromosome ends, not an enzyme (though telomerase acts on ends in some cells). The ribosome builds proteins from mRNA, not DNA. Thus, DNA polymerase III is the enzyme that adds nucleotides during DNA replication.

During DNA replication, nucleotides are added by DNA polymerases to the 3' end of the growing strand, using the parent strand as a template and synthesizing in the 5' to 3' direction. The main enzyme responsible for this synthesis in bacteria is DNA polymerase III, which carries out the bulk of the DNA elongation on both the leading and lagging strands (with primers provided by primase). Helicase, by contrast, unwinds the double helix but does not add nucleotides. The term telomere refers to chromosome ends, not an enzyme (though telomerase acts on ends in some cells). The ribosome builds proteins from mRNA, not DNA. Thus, DNA polymerase III is the enzyme that adds nucleotides during DNA replication.