Which of the following mechanisms is involved in double-strand DNA repair? a. Homology-dependent repair b. Nonhomologous end joining c. Mismatch repair d. A and B e. A, B, and C

When E. coli cells are mixed with recombinant vector DNA and subject to a stress such as heat shock, a small fraction of the cells will take up the plasmid DNA, a process known as :     A. Ligation.   B. Transformation.   C. Transfection.   D. Digestion.

49. The actions of the mismatch repair system become especially critical in regions of DNA that carry ________________sequences. A. Deleted B. New C. Old D. Repeated E. Both A and D

Which of the following is/are not required for DNAreplication to occur?a. DNA polymerase d. primersb. nucleotides e. helicasec. template DNA f. all are required

. Which of the following statements best describe the mismatch repair pathway?a. It is part of the 3′to 5′proofreading function of DNApolymerase.b. It acts after DNA replication by recognizing mismatched base pairs.c. It is activated by stalled replication forks.d. It is coupled to transcription.

Which proteins are responsible for the unwinding of the double-stranded DNA during  relication?   A. Primases.   B. Lyases.   C. Helicases   D. Topoisomerases   E. Ligases

A mutation caused by a base deamination or a tautomerization is called a a. silent mutation b. transition mutation c. nonsense mutation d. missense mutation

A small section of bacterial DNA template (anti-sense) strand has the following nucleotide sequence: GTT GTG ACG TAA A mutation in the above sequence involved a substitution of a single base, but did not affect the protein produced when the gene involved was transcribed and translated. Which of the following gene sequences could have the mutation described above? a. GTT GTG ACA TAA b. GTT GGG ACG TAA c. GTA GTG ACG TAA d. GTT GTG ACT TAA

Which of the following is the most accurate description of the E.coli replisome? a. Clamp loader positions two Pol III core polymerases on the leading strand and one Pol III core polymerase on the lagging strand b. Single strand template DNA forms two loops on the lagging strand while two Pol III core polymerases synthesize Okazaki fragments c. Okazaki fragments are synthesized in the opposite direction to movement of the replication fork d. Clamp loader only connects with Pol III core polymerases associated with the lagging strand e. Both b. and c. are accurate

The initial mechanism for repairing nucleotide errors in DNA is ________. a. mismatch repair b. DNA polymerase proofreading c. nucleotide excision repair d. thymine dimers