Practice Questions

TLS Online TPP Program

#Question id: 11584

Use the bar graph to answer the following question.

People who suffer from chronic fatigue syndrome (CFS) experience ongoing, debilitating fatigue. In one study, cortisol levels in the saliva during the first hour after waking were measured and compared between CFS patients and people without CFS (controls). The data is summarized in the graph. What can you infer from the data?

#Unit 7. System Physiology – Animal

A disruption to thyroid hormone production likely results in decreased cortisol in the saliva.
Cortisol is lower in CFS patients because they were just woken up.
The normal elevation in adrenocorticotropic hormone level in waking people is reduced in CFS patients.
CFS patients are generally more relaxed as demonstrated by their decreased stress response.

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TLS Online TPP Program

#Question id: 13049

#Unit 13. Methods in Biology

What is the role of goat anti-rabbit IgG horseradish peroxidase conjugate in the experiment?

TLS Online TPP Program

#Question id: 13050

#Unit 13. Methods in Biology

Which of the following expressions can be used in insects?

TLS Online TPP Program

#Question id: 13051

#Unit 13. Methods in Biology

Initiation of translation in higher eukaryotic organisms depends on a specific sequence of nucleotides surrounding the start (AUG) codon in the mRNA called……..

TLS Online TPP Program

#Question id: 13052

#Unit 13. Methods in Biology

What would be the effect on the PCR reaction if any of the following circumstances arose: 1) there are no primers in the reaction, 2) there are no dNTPs in the reaction, 3) there is no Taq polymerase in the reaction?

TLS Online TPP Program

#Question id: 13053

#Unit 13. Methods in Biology

What would the generally expected effect on the PCR reaction be of adjustments that increase the temperature of the annealing phase and the length of the elongation phase?

TLS Online TPP Program

#Question id: 13054

#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.

What would the expected effect be on a PCR reaction if the primers used were slightly shorter and more variable than the intended oligonucleotide sequences?