TLS Online TPP Program

#Question id: 799


The two cleavage reactions required to generate the miRNA from these primary transcripts are mediated by two distinct RNases. A characteristic of both these enzymes is that they recognize and cleave RNAs on the basis of the structure of their substrates rather than their specific sequence. Which of the following statement is INCORRECT regarding the cleavage reactions that produces a mature RNA?

#Unit 1. Structure and Function of Biomolecules
  1. Drosha resides in the cell’s nucleus, and the Drosha-catalyzed cleavage event occurs in that cellular compartment that generates a pre-miRNA which is ~65–70 nucleotides long.

  2. The pre-miRNA liberated by Drosha is exported to the cytoplasm, where the second RNA cleavage reaction, performed by Dicer, takes place which cleaves pre-miRNA 22 nucleotides from its ends.

  3. For processing by Drosha, ssRNA lacking significant secondary structure, is needed flanking each side (5’ and 3’) of the stem-loop. It is the ssRNA–dsRNA junctions that are in responsible for determining the cleavage specificity of Drosha.

  4. The RNase II family enzymes are specific for dsRNA and cleave it in a manner that leaves a 2-nucleotide overhang on the 3’ ends of the dsRNA product. This 3’ overhang is important for recognition of that RNA molecule by the next enzyme in the pathway, Dicer.

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TLS Online TPP Program

#Question id: 11425

#Unit 10. Ecological Principles

Walter's climate diagrams allow us to identify any months that have a water deficit. These are months in which:

TLS Online TPP Program

#Question id: 11426

#Unit 10. Ecological Principles

Which of the following biomes is associated with a mediterranean climate?

TLS Online TPP Program

#Question id: 11442

#Unit 10. Ecological Principles

Forests dominated primarily by evergreen trees with abundant lianas and epiphytes are found in which of the following biomes?

TLS Online TPP Program

#Question id: 11443

#Unit 10. Ecological Principles

To qualify as a Biodiversity Hotspot, an area must contain__:

A .At least 1,500 species of endemic vascular plants

B .At least 70 percent land covered by vascular plants

C .At least 25 threatened species of mammals

D .At least one protected area such as national park

 Choose the correct option from the codes given below:

TLS Online TPP Program

#Question id: 11444

#Unit 10. Ecological Principles

Ecologist have proposed following explanation to lead maximize biodiversity at tropic.

A. Higher productivity in the tropics allows for more species present

 B. Old communities have greater species than younger community

 C. Natural enemies such as predators and parasite limit competition in the tropics, which allows more species to coexist

D. Very less intensity of disturbances in the tropics promote high succession diversity

TLS Online TPP Program

#Question id: 12586

#Unit 10. Ecological Principles

A biome with dry and rainy seasons, trees in patches, and ground cover of tropical bunchgrass is called a