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The correct option is (a) 1961

The EXPLANATION: The MECHANISM by which all the GENES of an operon operate, was first elucidated in 1961 by Francois Jacob and Jacques Monod of the Pasteur Institute in Paris. An operon consists of structural genes, a promoter REGION, an operator region and a regulator gene.

Right CHOICE is (a) cell DIVISION

Best explanation: There are mutations that alter the INFORMATION of a single gene and then there are a WHOLE range of alterations that chromosomes may be SUBJECTED to. Most of these alterations occur during cell division, when the chromosomal content is replicated and then distributed evenly among daughter cells.

Right CHOICE is (C) lysine

To elaborate: Ubiquitination is the PROCESS of ADDING ubiquitin molecules to damaged or old proteins. The last Amino acid of ubiquitin is attached to a lysine residue on the substrate PROTEIN.

Correct ANSWER is (a) apolipoprotein B-48

The explanation: A shortened VERSION of the protein, apolipoprotein B-48 is generated as a result of RNA editing. This protein is produced in the SMALL intestines, responsible for the absorption of fats.

The CORRECT option is (a) True

For explanation: Microarrays USED in the CHROMATIN immuno-precipitation contain DNA SEQUENCES prepared from the intergenic sequences. Intergenic sequences are the non-coding, regulatory REGIONS of the genetic sequence.

The correct option is (B) False

Explanation: TATA box determines the SITE of the ignition of TRANSCRIPTION WHEREAS the frequency with which RNA polymerase transcribes a gene is DETERMINED by the CAAT and GC boxes.

The CORRECT option is (a) True

To EXPLAIN: Sequence-specific transcription factors can ACT as TRANSCRIPTIONAL activators by STIMULATION the expression of adjacent gene or as transcriptional repressors by inhibiting its transcription.

The correct OPTION is (c) disaccharide

To explain I would say: LACTOSE is a disaccharide comprised of glucose and GALACTOSE. Oxidation of this disaccharide can provide a BACTERIAL cell with metabolic intermediates and energy.

The correct option is (a) transcription factors

Easy explanation: Deletion maps are used by the RESEARCHERS to DETERMINE which SITES in the genome interact with a particular transcription factor. In this procedure, cells are TRANSFECTED with altered DNA molecules that contain deletions.

Right choice is (d) glucose-effect

The best I can explain: The lac operon is negatively REGULATED by repressor PROTEINS. There is ALSO a positive CONTROL that prevails in the lac operon, called the glucose-effect. When glucose is present in the medium along with other SUBSTRATES, the catabolism of the letter is suppressed.

The correct choice is (c) UTRs

The best explanation: The untranslated REGIONS of messenger RNAs are CALLED untranslated regions. These regions do not code for proteins but play a vital role in translational-level CONTROL.

The correct answer is (d) inheritance

The EXPLANATION is: Whether a gene REMAINS active or INACTIVE during MAMMALIAN development depends solely on whether they were brought into the ZYGOTE by egg or sperm.

Right answer is (d) 2006

Easy explanation: Stem cells from CHICKEN and murine EMBRYOS were EXTENSIVELY studied by Shinya Yamanaka and Kazutoshi Takahashi and in 2006 they PUBLISHED a paper REGARDING the role of transcription factors in stem cells.

The correct choice is (a) True

Easy explanation: The STRUCTURAL genes code for the enzymes involved in metabolic PATHWAYS. The genes are LOCATED adjacent to each other and the RNA polymerase moves through the structural genes one after the other, TRANSCRIBING all of the genes into a single mRNA.

Right option is (a) mutations

To EXPLAIN I would SAY: CHROMOSOMAL aberration refers to the change in number of CHROMOSOMES or any other associated errors. There are various types of chromosomal ABERRATIONS including inversions, translocations, duplications etc. Mutation however is a broader term.

Correct CHOICE is (b) cytoplasm

The EXPLANATION: Pre-synthesized MRNAS are stored in the cytoplasm in an inactive STATE for future translation. When translation of these stored mRNA TAKES place, the inhibitory proteins are removed and poly-adenine tail is lengthened.

Correct answer is (d) DNA-digesting enzymes

For explanation: DNA-digesting enzymes are used in DNA footprinting to determine the genetic sequences that are PROTECTED by transcription factors. The basic principle of the technique is that when transcription factors bind to a PARTICULAR sequence, it protects the sequence from DIGESTION by nucleases.

Right OPTION is (c) AT

To elaborate: There are THREE proximal promoter elements TATA, CAAT and GC boxes. They are called so because of their presence at 100 to 150 base pairs upstream from the GENE.

Correct CHOICE is (a) 15

The explanation is: Prader-Willi syndrome (PWS) is an INHERITED neurological disorder caused due to a deletion in the imprinted genes of chromosome 15 inherited from the father. It is characterized by mental retardation, obesity and UNDERDEVELOPMENT of GONADS.

Right option is (b) 2

To explain I would say: The transcription factors USUALLY contain TWO domains, activation domain that interacts with other DNA-binding PROTEINS thereby regulating transcription, and DNA-binding domain that BINDS to the DNA SEQUENCE.

The CORRECT answer is (B) Translational-level

For explanation: Translational-level control determines for how LONG a period, and how OFTEN a particular messenger RNA molecule is translated. The translational-level control is prevalent in the CYTOPLASM.

The correct choice is (c) 3

The best I can explain: The lac operon is an inducible operon that CONSISTS of 3 tandem STRUCTURAL genes namely the z gene, y gene and the gene; encoding the β-galactosidase, galactoside permease and thiogalactoside transacetylase RESPECTIVELY.

The correct option is (c) nervous system

To elaborate: RNA editing is not as WIDESPREAD as alternative splicing but it is PARTICULARLY important in nervous system. A significant number of NEURAL messages have ONE or more adenines converted to inosines.

Right answer is (a) transcription

To explain: RNA EDITING is the process TAKING PLACE after the RNA is transcribed where specific nucleotides are CONVERTED to other nucleotides, GENERATING amino acid substitutions.

Right ANSWER is (c) 5

Easiest explanation: The CRY-of-the-cat syndrome arises DUE to a deletion in human chromosome 5. This was elucidated by Jerome Lejeune while he OBSERVED a newborn with FACIAL malformations and a cry resembling that of a suffering cat.

Correct ANSWER is (c) lactose

To EXPLAIN I would say: When lactose is PRESENT in the medium, it binds to the REPRESSOR protein changing its conformation while preventing the former’s binding at the operator region. Thus the structural genes are transcribed and lactose is catabolized, THEREFORE lactose acts as an inducer in the lac operon.

Right option is (d) regulatory gene

Easiest explanation: In a bacterial OPERON, promoter region and operator region are located upstream of the cluster of STRUCTURAL GENES, and the regulatory genes are located DOWNSTREAM of the structural genes.

Right choice is (a) True

Explanation: Under MINIMAL conditions, when GLUCOSE is PRESENT as an energy source there is no need for the CELL to utilize lactose. Under such conditions an AVERAGE cell contains fewer than 5 copies of enzyme β-galactosidase and single copy of associated mRNA.

The correct choice is (c) 3

The best I can explain: DUPLICATION occurs due to the presence of more COPIES of a gene than normal. PARTIAL trisomy is the condition where a gene is repeated thrice, in PLACE of two normal copies of the gene there are three copies.

Right answer is (a) True

For explanation I would say: Inversions are chromosomal aberrations that OCCUR when there are two breaks in the chromosome and the SEGMENT amidst the breaks becomes resealed in a reverse ORIENTATION. During crossing over the aberrant chromosome does not pair properly with its homologue, the gametes then generated by meiosis either possess DUPLICATION or a deletion.

The correct choice is (b) alternative splicing

The best I can explain: Alternative splicing regulates gene expression at the level of RNA processing. It helps a gene encode more TWO or more RELATED PROTEINS.

Right ANSWER is (c) abnormal meiosis

Best explanation: Meiosis is the cellular process where a SINGLE cell divides twice to give RISE to 4 distinct cells, the gametes. Zygotes containing a chromosomal deletion are a PRODUCT of abnormal meiosis.

Correct option is (b) beta-subunit

To explain I WOULD say: Once the protein is polyubiquitinated, it is ready for enzymatic degradation by the PROTEASOME. The cap of proteasome RECOGNIZES the protein and REMOVES the ubiquitin CHAIN and unfolds the target protein.

Correct answer is (a) True

For explanation: Although EXACT FACTORS that determine the longevity of a PROTEIN are not yet clear. One of the determinants is amino acid SEQUENCE at the N-terminus of the polypeptide. Polypeptides that terminate in arginine and LYSINE are short-lived.

Right answer is (d) 30

Best EXPLANATION: When an mRNA leaves the nucleus, it contains ROUGHLY 200 ADENINE RESIDUES (in the poly-adenine tail), but these are nibbled AWAY by a deadenylase. The degradation of mRNA starts when the residues are reduced to 30.

The CORRECT choice is (b) bicoid

To explain I would say: During oogenesis, MESSENGER RNA TRANSCRIBED from the bicoid GENE of fruit fly is specifically localized at the anterior end of the oocyte while MRNA from the oskar gene becomes localized at the opposite end.

Correct choice is (B) Poly(A) tail

The best I can explain: The MRNA undergoes post transcriptional modification to PREVENT premature degradation in the cytoplasm. The mRNA undergoes 5’ CAPPING by a methylated guanosine residue and a 3’ Poly-A-tail using the Rho protein.

The correct answer is (C) 6

The EXPLANATION is: In the leucine-zipper motif, the leucines OCCUR every SEVENTH amino acid along the length of alpha-helix. The alpha-helix is the PART of the DNA-binding domain that fits into the major groove of DNA.