Molecular Biology Questions for CSIR NET Examination (Part-7)

You have discovered a new transposon, TnX, and would like to identify its mode of replication. A heteroduplex of the TnX sequence is made with a few mismatches and introduced into bacteria. The newly transposed genomic loci are sequenced. You find that the sequence of the transposon matched exactly with one of its parent strands. This suggests that:  (CSIR_2017_II)

To assess the impact of a newly identified drug when added to a culture of subconfluent HeLa cells, a researcher analyzes the fluorescence activated cell sorting (FACS) profile of untreated (- Drug) versus treated (+ Drug) cells.

Based on the FACS profile shown above, this drug inhibits (CSIR_2017_II)

Following table lists the two major forms of DNA duplexes, conformation of base attached to the sugar and the nature of major and minor grooves.

Which of the following combination correctly depicts the types of DNA duplexes and their properties (numbered within bracket)? (CSIR_2017_II)

Imagine the following RNA sequence is translated in the mammalian cytosol and mitochondria. RNA sequence:
     AUG AUA CUG UGA CUU AGG CUC UAA
Following are some putative peptide sequences

Find out the correct combination of peptides made in the cytosol and mitochondria. (CSIR_2017_II)

Cell cycle checkpoints are surveillance mechanisms that ensure order and fidelity of events of the cell cycle. Given below are some of the checkpoint proteins and their


Match the checkpoint protein with its function. (CSIR_2017_II)

In all organisms, it is critical that replication initiation be tightly controlled to ensure that chromosome number and cell number remain appropriately balanced. Given below are several statements regarding regulation of replication in E. coli.

(A). Hemimethylation and sequestration of oriC (origin of replication) by a protein called SeqA prevents initiation of replication.
(B). Availability of DnaA protein is an important requirement for initiation of replication.
(C). The ratio of ADP: ATP is important as high level of ADP is required for initiation of replication.
(D). Recruitment of Hda protein by sliding clamp inhibits ATP hydrolysis required for initiation of replication.

Which of the above statements are NOT true? (CSIR_2017_II)

In E. coli, though DNA polymerase I (Pol I) plays an essential role in the replication process, it is not the major polymerase. Instead, the enzyme responsible for advancement of replication fork is Pol III. From the four DNA structures (A, B, C and D) given below, students made several interpretations about the shorter arm being extended by Pol I and/or Pol III.

Which one of the interpretation written below is correct? (CSIR_2017_II)

tRNA genes of a Gram positive bacteria were sequenced. While some of the genes possessed sequence corresponding to the –CCA end of the tRNA, others did not. Interestingly, even the genes that lacked the sequence corresponding to the –CCA end of the tRNA were found to code for a functional tRNA. This is because (CSIR_2017_II)

A construct (shown below) was generated to access the activity of bidirectional promoter (A and B) which has a common regulatory DNA element (X). The construct was used to transform E. coli.

The activity of the promoter (as shown in the graph below) is recorded in the presence of increasing levels of an E. coli encoded regulatory protein which binds to DNA element X.

The above experiment is repeated in a mutant E. coli with mutation which abolishes binding of the regulatory protein to element X. Which one of the following graphs best depicts the activity of the reporter genes in the mutant strain? (CSIR_2017_II)

In Burkitt’s Lymphoma a reciprocal translocation between chromosome 8 and 14 is observed. If an individual is heterozygous for this translocation, the consequence in meiosis will be as follows:

(A). Four chromosomes, i.e., normal chromosome 8 and 14, and translocated chromosome 8 and 14, pair together
(B). The two normal chromosomes 8 and 14, and two translocated chromosomes pair separately
(C). All gametes produced from this meiosis are non-viable as they have deletions and duplications
(D). In one of the cross configurations called "alternate segregation" all gametes having normal or translocated chromosomes, survive
(E). The gametes having normal chromosomes only survive while all gametes having translocated chromosomes are non-viable, hence the translocations are used as crossover suppressors

Which of the following combinations best describes the meiotic consequences for the translocation described above? (CSIR_2017_II)