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TLS Online TPP Program

#Question id: 4109

When E. coli is grown on a medium containing a mixture of glucose and lactose, it proliferates with complex kinetics. The bacteria proliferate faster at the beginning than at the end, and there is a lag between these two phases when they virtually stop dividing. Assays of the concentrations of the two sugars in the medium show that glucose falls to very low levels after a few cell doublings, but lactose remains high until near the end of the experimental time course (not shown). Although the concentration of lactose is high throughout most of the experiment, β-galactosidase, which is regulated as part of the Lac operon, is not induced until more than 100 minutes have passed. Choose correct explanation why the Lac operon is not induced by lactose during the rapid initial phase of bacterial proliferation

A. The rapid bacterial growth at the beginning of the experiment results from the metabolism of glucose. The slower growth at the end results from metabolism of lactose.

B. CAP and the Lac repressor mediate induction in the situation

C. The bacteria stopped growing in the middle of the experiment because they ran out of glucose but did not yet possess the enzymes necessary for lactose metabolism

D. Induction of the Lac operon requires that two conditions be met: lactose must be present and glucose must be absent.

#Unit 3. Fundamental Processes

  1. A, B, C & D      

  2. B, C & D                

  3. A, D & E  

  4. E only

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TLS Online TPP Program

#Question id: 13057

#Unit 13. Methods in Biology

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.
How primer concentration leads to decrease in PCR efficiency?
TLS Online TPP Program

#Question id: 13058

#Unit 13. Methods in Biology

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.
Which of the following true about real time PCR?
TLS Online TPP Program

#Question id: 13059

#Unit 13. Methods in Biology

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.
Efficiency during ligation of blunt ended insert and vector cannot be cannot be enhanced by means of…..
TLS Online TPP Program

#Question id: 13060

#Unit 13. Methods in Biology

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: 13061

#Unit 13. Methods in Biology

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.
Arrange in the order of their increasing capacity:
TLS Online TPP Program

#Question id: 13062

#Unit 13. Methods in Biology

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.
A restriction enzyme cleaves a circular plasmid vector to produce fragments : 1kb, 0.3kb, 2kb, 1kb and 0.3kb. How many bands will be visible on agarose gel?