TLS Online TPP Program

#Question id: 780


Drosha and Pasha:

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. are found in introns of transcribed genes;

  2. participate in mRNA degradation;

  3. cleave individual stem-loops;

  4. convert single-stranded to double-stranded to ssRNA.

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TLS Online TPP Program

#Question id: 12100

#Unit 10. Ecological Principles

Prairie dogs once covered the expanses of the Great Plains. Their grazing made the grass more nutritious for the huge herds of bison, and a variety of snakes, raptors, and mammals   preyed on the rodents. In fact, the black- footed ferret (now endangered) specialized in prairie dog predation. Today, growing housing and agricultural developments have covered many prairie dog towns. Which of the following statements about prairie dogs is true?

TLS Online TPP Program

#Question id: 5443

#Unit 8. Inheritance Biology

Two varieties of maize averaging 25 and 125 inches in height, respectively, are crossed. The F1 progeny is quite uniform averaging 75 inches in height. Plant height is control by 3 QTL, what is the probability of plant with 25 inch height in F2 generation?

TLS Online TPP Program

#Question id: 19098

#Unit 4. Cell Communication and Cell Signaling

Quorum sensing in E. carotovora is mediated by

TLS Online TPP Program

#Question id: 15418

#Unit 5. Developmental Biology

In which type of interaction, the responding tissue has already been specified and needs only an environment that allows the expression of particular traits?

TLS Online TPP Program

#Question id: 4973

#Unit 11. Evolution and Behavior

Fossils of Lystrosaurus, a dicynodont therapsid, are most common in parts of modern-day South America, South Africa, Madagascar, India, South Australia, and Antarctica. It apparently lived in arid regions, and was mostly herbivorous. It originated during the mid-Permian period, survived the Permian extinction, and dwindled by the late Triassic, though there is evidence of a relict population in Australia during the Cretaceous. The dicynodonts had two large tusks, extending down from their upper jaws; the tusks were not used for food gathering, and in some species were limited to males. Food was gathered using an otherwise toothless beak. Judging from the fossil record, these pig-sized organisms were the most common mammal-like reptiles of the Permian.Which of Lystrosaurusʹ features help explain why these organisms fossilized so abundantly?

I. the presence of hard parts, such as tusks

II. its herbivorous diet

III. its persistence across at least two geological eras

IV. its widespread geographic distribution

V. its mixture of reptilian and mammalian features