TLS Online TPP Program

#Question id: 4314


A researcher introduces double-stranded RNA into a culture of mammalian cells and can identify its location or that of its smaller subsections experimentally, using a fluorescent probe. Some time later, she finds that the introduced strand separates into single-stranded RNAs, one of which is degraded. What does this enable the remaining strand to do?

#Unit 3. Fundamental Processes
  1. attach to histones in the chromatin

  2. bind to complementary regions of target mRNAs

  3. activate other siRNAs in the cell

  4. bind to noncomplementary RNA sequences

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TLS Online TPP Program

#Question id: 12341

#Unit 10. Ecological Principles

The figure shows population growth trajectories over time (as indicated by the arrows) of two stored-grain beetle  species  when  grown  together  under  constant  conditions.  Three  experiments  were  performed  that  differed only in the initial densities of the two species. Which of the following is the best interpretation of the experimental results?


TLS Online TPP Program

#Question id: 12342

#Unit 10. Ecological Principles

Which of the following is a biological attribute that would most likely allow a species to become cosmopolitan in distribution?

TLS Online TPP Program

#Question id: 12343

#Unit 10. Ecological Principles

Hybrids between some related species of plants are sterile because the parent plants had different chromosome numbers. Occasionally the chromosome number of such a hybrid  plant doubles spontaneously. Which of the following best describes the descendants of those plants with the double chromosome number?

TLS Online TPP Program

#Question id: 12344

#Unit 10. Ecological Principles

The concept of punctuated equilibrium refers to

TLS Online TPP Program

#Question id: 12345

#Unit 10. Ecological Principles

Shannon's index of diversity is calculated using the equation below, where pi is the proportion of the ithShannon's index of diversity is calculated using the equation below, where pi is the proportion of the ith species and ln is natural logarithm. For a community with a given number of species, which of the following statements is true? species and ln is natural logarithm. For a community with a given number of species, which of the following statements is true?


TLS Online TPP Program

#Question id: 12346

#Unit 10. Ecological Principles

The schematic below shows the relationship between survivorship with age (relative to maximum lifespan) in Species 1 (dashed line) and Species 2 (solid line). Which of the following inferences is compatible with this figure?