TLS Online TPP Program

#Question id: 15595


How might the function of extracellular endonucleases help protect the bacterium from infection by viruses?

#Unit 8. Inheritance Biology
  1. They would prevent the virus from binding to the outside of the bacterial cell.
  2. They would destroy the viral coat, so it cannot inject its genetic material
  3. They would destroy cut the viral DNA into small pieces
  4. All of the above.
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TLS Online TPP Program

#Question id: 8296

#Unit 9. Diversity of Life Forms

Giardia intestinalis can cause disease in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals, thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics. In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species.


According to the phylogenetic tree in the figure above, G. intestinalis constitutes a ________ group.

TLS Online TPP Program

#Question id: 8680

#Unit 9. Diversity of Life Forms

Giardia intestinalis can cause disease in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals, thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics. In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species


By examining the phylogenetic tree diagrammed in the figure above, what conclusion can you draw about the species G. microti?

TLS Online TPP Program

#Question id: 8682

#Unit 9. Diversity of Life Forms

Giardia intestinalis can cause disease in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals, thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics. In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species


Which of the following changes would a modern systematist be most likely to make after learning of the results of the rRNA analyses?

TLS Online TPP Program

#Question id: 8683

#Unit 9. Diversity of Life Forms

Use the following information to answer the question.

Refer to the figure. Which of the following forms a monophyletic group?

TLS Online TPP Program

#Question id: 8684

#Unit 9. Diversity of Life Forms

Use the following information to answer the question.



Which of the following trees, if any, depicts the same relationship among species as shown above?

TLS Online TPP Program

#Question id: 8685

#Unit 9. Diversity of Life Forms

Which of the following would be most useful in creating a phylogenetic tree of a taxon?