Precision will be reduced, but yield will be increased

Optimisation of a PCR reaction is often a compromise between the competing demands for precision, efficiency and yield. Although the specific effects may vary, generally, increasing the annealing temperature will increase non-specific primer binding and reduce precision. Increasing the length of the elongation phase will reduce the proportion of incomplete newly-synthesised strands and therefore increase yield. In this case, the potential effect on efficiency is unclear. Increasing the elongation phase would increase the reaction time, but the time taken to ramp down to a lower annealing temperature would be reduced.

In blue white screening insertional activation of Beta-D-galactosidase will give rise to

TLS Online TPP Program

#Question id: 15607

#Unit 12. Applied Biology

In gene transformation over high expression can be achieved by expressing the gene 

1. Inducible promoter

2. Constitutive  promoter

3. Terminator sequence

4. Increasing copy no. of gene

Which of the following are correct

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#Question id: 15608

#Unit 12. Applied Biology

Melanins are light-absorbing biopolymers useful as topical sunscreens, sunlight-protective coatings for plastics, etc. Which gene is used for producing melanin. 

TLS Online TPP Program

#Question id: 15609

#Unit 12. Applied Biology

Most bacteria, some protozoans  and even archaea use poly-β-hydroxybutyrate, a polymerized form of β-PHB, as 

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#Question id: 15615

#Unit 13. Methods in Biology

The three stop codons are (I) 5’UAG3’, (II) 5’UAA3’, and (III) 5’UGA3’. when mutagens that specifically induce G•C to A•T mutations on 5’, then what will be the result?

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#Question id: 15616

#Unit 13. Methods in Biology

The diagram below shows the F factor and a portion of the E. coli chromosome that has three different insertion sequences (IS) of the same type as is carried on F.

                     

Describe the three different Hfrs (Hfr #1, Hfr #2 and Hfr #3) that can be formed by recombination between the IS on F and each of the IS sequences on the chromosome. Some including the positions of each of the markers (A, B, C, and D) and state which of these markers would be transferred early?

TLS Online TPP Program

#Question id: 15617

#Unit 13. Methods in Biology

Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition you have a wild type (Lac+) strain carrying a Tn5 insertion known to be near several Lac genes on the E. coli chromosome. You grow P1 phage on this strain and use the resulting phage lysate to infect the lac1– strain, selecting for kanamycin resistance (Kanr). Among 100 Kanr transductants, you find that 82 are Lac– and 18 are Lac+. Express the distance between Tn5 and the lac1– mutation as a cotransduction frequency;