You have isolated two temperature-sensitive mutations in phage l that you suspect may be in the same gene. These phage mutants are called ts-1 and ts-2. Each mutant will form plaques at 35˚C but not at 42˚C. You cross ts-1 to ts-2 phage by coinfecting E. coli at the permissive temperature of 35˚C. When the resulting phage lysate is plated at 35˚C you count 10,000 plaques per ml of phage lysate, but when the same phage lysate is plated at 42˚C, there are only 80 plaques per ml. Find out the relative order of sm, ts-1 and ts-2?

TLS Online TPP Program

#Question id: 34173

#Unit 3. Fundamental Processes

The 3’–5’ exonucleolytic activity is found in which subunit of bacterial DNA Polymerase III

TLS Online TPP Program

#Question id: 34174

#Unit 3. Fundamental Processes

Once bound to a primer:template junction, DNA polymerase interacts tightly with much of the double stranded portion of the DNA by

TLS Online TPP Program

#Question id: 34175

#Unit 3. Fundamental Processes

A. For processive DNA synthesis, proofreading occurs without releasing the DNA from the polymerase

B. When a mismatched base pair is present in the polymerase active site, the primer:template junction is destabilize

C. The DNA polymerase active site binds such a mismatched template poorly, but the exonuclease active site has a 10-fold higher affinity.

D. The incorrect nucleotide is removed by the 5’-3’-exonuclease nuclease activity

Choose true and false

TLS Online TPP Program

#Question id: 34176

#Unit 3. Fundamental Processes

A. The lagging strand must be synthesized in the form of Okazaki fragments. 

B. Both strands are synthesized discontinuously. 

C. Not all of the fragment population represents bona fide Okazaki fragments; some are pseudofragments

D. Primers start with the sequence pppAG positioned opposite the sequence 3’–GTC-5’ in the template

Choose true and false

TLS Online TPP Program

#Question id: 34177

#Unit 3. Fundamental Processes

Which of the following combination of the statements regarding polA mutants is correct

A. fail to join their Okazaki fragments 

B. fail to removes the RNA primer

C. fail to removes the mismatch errors

D. fail to synthesis Okazaki fragments 

TLS Online TPP Program

#Question id: 34178

#Unit 3. Fundamental Processes

A. SSBs interact with ssDNA in a sequence-independent manner. 

B. SSBs primarily contact ssDNA through electrostatic interactions with the phosphate backbone and stacking interactions with the DNA bases.

C. SSBs interact with ssDNA in a sequence dependent manner via hydrogen bonds with phosphate backbone

D. SSBs shows sigmoidal behaviour of binding

Choose true and false