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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?

#Part-B Specialized Branches in Biotechnology

  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: 21726

#Part-B Specialized Branches in Biotechnology

For a first order chemical reaction, the rate constant
TLS Online TPP Program

#Question id: 21727

#Part-B Specialized Branches in Biotechnology

In the reaction H2O2(aq) → H2O(l) + ½ O2(g), the initial concentration of H2O2 is 0.2546 M, and the initial rate of reaction is 9.32×10–4 M s–1. What will be [H2O2] at t = 35 s?
TLS Online TPP Program

#Question id: 21728

#Part-B Specialized Branches in Biotechnology

In the reaction A → products, we find that when [A] has fallen to half of its initial value, the reaction proceeds at the same rate as its initial rate. Is the reaction zero order, first order, or second order?
TLS Online TPP Program

#Question id: 21729

#Part-B Specialized Branches in Biotechnology

In the reaction, A → products, with the initial concentration [A]0 = 1.512 M, [A] is found to be 1.496 M at t = 30 s. With the initial concentration [A]0 = 2.584 M, [A] is found to be 2.552 M at t = 1 min. What is the order of this reaction?
TLS Online TPP Program

#Question id: 21731

#Part-B Specialized Branches in Biotechnology

The smog constituent peroxyacetyl nitrate (PAN) dissociates into peroxyacetyl radicals and NO2(g) in a first order reaction with a half-life of 32 min. 
If the initial concentration of PAN in an air sample is 2.7×1015 molecules/L, what will be the concentration 2.24 h later?
TLS Online TPP Program

#Question id: 21733

#Part-B Specialized Branches in Biotechnology

A rate law __________.