Question

NA primase is TRUE? 27. Which ONE of the following statements about DNA primase is in polymerase cannot extend a new A) It is necessary for DNA synthesis because DNA polymerase canno strand in the 3 to 5' direction. B) It proofreads bases added by DNA polymerase. C) It is a type of RNA polymerase. D) It has terminal transferase activity. 28. How many of the following statements about PCNA are TRUE? • It encircles ssDNA. • It is an ATPase. . It stimulates the activity of DNA polymerase d. • It stimulates the activity of DNA polymerase e. • It stimulates the activity of DNA polymerase a. B) 2 C) 3 D) 4 29. You wish to increase the error rate of DNA synthesis by E. coli for a random mutagenesis experiment in the lab. What would be the best way to do this? A) Inactivate DNA polymerase III so the cell is forced to use DNA pol I. B) Mutate the DNA polymerase Ill active site so it is forced to use exonuclease activity C) Inactivate cellular pyrophosphatases. D) Inactivate the exonuclease active site of DNA polymerase III.

Answer 1

Q27. Ans: Option C.

DNA primase is a type of RNA polymerase which help in catalysing the synthesis of small segment of RNA or DNA in some organisms called a primer which is complement to single stranded DNA template.

Primase is crucial in DNA replication since no known replicative DNA polymerases can begin a DNA strand synthesis without an initial RNA or DNA(for temporary DNA elongation) priming.

After this elongation the fragment of RNA is replaced by an exonuclease of 5' to 3' and replenished with DNA.

Terminal transferase function Primases can, independent of a template, be able to add nucleotides to the end of a 3' end of DNA.Primase activity may also be present in other enzymes involved in DNA replication, such as helicases