The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma that have apparently undergone speciation from ancestral stock since the last glacial retreat about 10,000 years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species?

TLS Online TPP Program

#Question id: 11580

#Unit 7. System Physiology – Animal

Melatonin is secreted by the ________.

TLS Online TPP Program

#Question id: 31035

#Unit 4. Cell Communication and Cell Signaling

Which of the following is not a RTK ligand? 

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?

TLS Online TPP Program

#Question id: 5846

#Unit 8. Inheritance Biology

The bacteriophage can lysogenize after infecting a bacterium, i.e. integrate into the host bacterial chromosome by site-specific recombination, and may reside there for many generations before an excision event regenerates the viral genome in an infective form.  Which one of the following is not a component of these events?

TLS Online TPP Program

#Question id: 28371

#Unit 5. Developmental Biology

At which cell of the embryo where the Gurken protein is diffuses and do not allow to synthesizes of pipe protein ?