Question

paul is studying dna replication in a cell - free system. his solution contains the template dna, dna polymerase i, primase, helicase, and all four dntps. however, when he begins the reaction, he observes that short dna fragments are synthesized, but then the reaction stops suddenly. addition of which component would most likely restore dna synthesis?
dna polymerase iii
single - strand binding proteins
dna ligase $$
more ntps
atp

Explanation:

In DNA replication, short fragments (Okazaki fragments) are formed on the lagging - strand. DNA ligase is required to join these fragments together. Since short DNA fragments are synthesized but the reaction stops, the likely missing component is DNA ligase which can catalyze the formation of phosphodiester bonds between adjacent nucleotides to continue DNA synthesis.

Answer:

C. DNA ligase