Which Enzyme Joins the Paired Sticky Ends of DNA Fragments

Question

Which enzyme joins the paired sticky ends of DNA fragments?  
A) Reverse transcriptase
B) Restriction enzyme
C) DNA ligase
D) DNA polymerase
E) Polynucleotide kinase

Accepted Answer

DNA ligase joins the paired sticky ends of DNA fragments by catalyzing the formation of phosphodiester bonds between the 3'-hydroxyl end of one DNA fragment and the 5'-phosphate end of the other DNA fragment, creating a continuous strand of DNA. Reverse transcriptase is an enzyme that synthesizes a complementary DNA copy from an RNA template, restriction enzymes cut DNA at specific recognition sites, DNA polymerase extends DNA strands during DNA replication or repair, and polynucleotide kinase is involved in phosphorylation of DNA and RNA molecules.