Practice Questions

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

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.
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.
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.
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.

More Questions

#Question id: 2968

#Part-B Specialized Branches in Biotechnology

What is the name of the microtubule-organizing center found in animal cells as an identifiable structure present during all phases of the cell cycle?

#Question id: 2969

#Part-B Specialized Branches in Biotechnology

In the cells of many eukaryotic species, the nuclear envelope has to disappear to permit which of the following events in the cell cycle?

#Question id: 2976

#Part-B Specialized Branches in Biotechnology

Match the following Regulators with its functions.

Column I	Column II
A. Wee1 kinase	i. Degradation of phosphorylated Sic1 or p27KIP1
B. Cdc25A phosphatase	ii. Induces degradation of B-type cyclins
C. APC/CCdc20	iii. Activates vertebrate S phase CDKs
D. SCF	iv. Inhibits CDKs

Which of the following is correct?

#Question id: 2982

#Part-B Specialized Branches in Biotechnology

Match the following proteins (Column I) with their functions (Column II) during cell cycle.

Column I	Column II
A. Cdc25C phosphatase	i. Activates vertebrate S phase CDKs
B. INK4	ii. Activation of Mitotic CDKs
C. Cdc25A phosphatase	iii. Binds and inhibits G1 CDKs
D. APC/CCdc20	iv. Degradation of securin

#Question id: 2987

#Part-B Specialized Branches in Biotechnology

Following statements are regarding the goals of gap phases.

(i) to prepare for the next phase of the cell cycle.

(ii) to check that the previous phase of the cell cycle has been completed appropriately.

(iii) to inhibits CDKs activity.

(iv) to enhance servillance mechanisms.

Which of the following is correct?

#Question id: 2988

#Part-A Aptitude & General Biotechnology

Use the figure to answer the question below.

If the cell whose nuclear material is shown in the figure continues toward completion of mitosis, which of the following events would occur next?