TLS Online TPP Program

#Question id: 19841


Which of the following is true regarding Reverse transcriptase ?

#Unit 13. Methods in Biology
  1. is used to proch1ce cDNA (complementary DNA) copies of, usually, mRNA that are used for creation of cDNA libraries
  2. for removing 5' -phosphate from DNA ends.
  3. for addition of phosphate group to an end having a free 5'-0H.
  4. for removal of single-stranded protrusions from ends; both 3'- and 5'-extensions are removed.
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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: 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: 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: 12340

#Unit 10. Ecological Principles

Keystone species are thought to have profound effects on the structure and composition of ecological communities because they

TLS Online TPP Program

#Question id: 12339

#Unit 10. Ecological Principles

If a species is a keystone predator, then its removal from a community should

TLS Online TPP Program

#Question id: 12338

#Unit 10. Ecological Principles

Ecology as a discipline directly deals with all of the following levels of biological organization except