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Right ANSWER is (c) AGG

Best EXPLANATION: There are a few exceptions to the universality of genetic code that are FOUND to occur in codons of mitochondrial MESSENGER RNAs. AGG and AGA are read as stop codons rather than as arginine.

The correct option is (a) a

Easiest EXPLANATION: The AMINO acid attaches at the 3’ end of a transfer RNA molecule, whereas the OPPOSITE end bears the ANTICODON. The region of 3’ and downwards is called the amino-acid acceptor arm.

Right choice is (a) petunia

Explanation: The studies began in 1990 using petals of petunia FLOWER plants, that ultimately led to the DISCOVERY of posttranscriptional gene SILENCING (PTGS).

The correct choice is (c) let-7

Easiest explanation: In 2000, it was SHOWN that a 21-nucleotide RNA, let-7 present in small worms is HIGHLY conserved THROUGHOUT evolution. Humans encode several RNAS IDENTICAL to let-7.

The correct CHOICE is (a) protein complex

For explanation I would say: TFIID is a transcription FACTOR in eukaryotes but essentially it is a multiprotein complex made up of many smaller proteins which also includes the TATA BINDING protein.

Correct option is (C) 45S

To ELABORATE: The 45S RNA MOLECULE is a pre-rRNA, of length 13,000 nucleotides. It is cleaved into 18S, 5.8S and 28S mature rRNA. Most of the pre- rRNA is SPLICED and reduced in length before turning into mature rRNA.

The correct option is (a) GLUTAMIC ACID

For explanation: There is valine in sickle CELL hemoglobin, in place of glutamic acid in NORMAL cell hemoglobin.

Right OPTION is (b) False

For explanation: The UGA is a stop codon in all organisms with one exception, the codons of mitochondrial MESSENGER RNA. UGA is READ as TRYPTOPHAN rather than a translation stop.

The correct ANSWER is (a) True

To elaborate: Eukaryotic mRNAs have SPECIAL modifications on 5’ and 3’ termini, which are not present in prokaryotic mRNAs or on rRNAs or tRNAs. These include POLY(A) tail on 3’ end and methylated GUANOSINE cap on 5’ end.

The correct OPTION is (a) humans

Explanation: Transfer RNAs (called TRNAS) play an important role in peptide synthesis. Humans contain about 1300 tRNA genes GREATER than other ORGANISMS mentioned. BACTERIA has least number of tRNA genes.

The correct choice is (C) 1908

Easiest explanation: Archibald Garrod was a Scottish physician who in 1908 REPORTED that the absence of an ENZYME LED to an inherited DISORDER Alcaptonuria.

Correct ANSWER is (a) polyphenylalanine

Best explanation: The first artificially synthesized protein is polyphenylalanine, synthesized using the poly(U) genetic sequence. After the successful synthesis of polyphenylalanine, it was confirmed that the codon UUU SPECIFIES PHENYLALANINE.

Right option is (b) Argonaute

The best explanation: Argonaute proteins are components of the RNA induced SILENCING complex. This RISC is involved in RNAI and therefore involved in gene silencing.

Right answer is (a) True

Best explanation: RNA INTERFERENCE (RNAi) is thought to have evolved as a type of genetic IMMUNE system, protecting the organism from UNWANTED foreign genetic material such as dsRNA, which is otherwise non-existent in cells.

Correct option is (b) hnRNA

The EXPLANATION is: Heterogeneous nuclear RNAs (hnRNA) are LARGE MOLECULAR weight RNA molecules, present exclusively in the NUCLEUS. They are precursors to the cytoplasmic mRNAs.

Right answer is (b) False

Easy explanation: 5S rRNA is PRESENT as PART of the large ribosomal subunit in both eukaryotic and prokaryotic ORGANISMS. UNLIKE other types of rRNA, 5S rRNA is transcribed from a separate primary transcript.

The correct choice is (c) snoRNA

The explanation: The processing of pre- RRNA is done using the SMALL nucleolar RNAs (called snoRNA) along with some proteins. Processing of pre- rRNA INCLUDES removal of non-coding SEQUENCES and posttranscriptional modifications.

Correct choice is (d) promoter

To EXPLAIN: The RNA polymerases are not capable of recognizing the PROMOTERS located on the DNA to be transcribed. Transcription FACTORS assist the RNA POLYMERASE in doing so.

Right choice is (d) trypsin

Explanation: In 1956 Vernon Ingram of Cambridge University discovered the molecular CONSEQUENCE of MUTATION that CAUSES SICKLE cell ANEMIA. He used the proteolytic enzyme, trypsin, to cleave the hemoglobin.

Correct answer is (a) Anticodon

Explanation: The part of tRNA that participates in complementary interaction with the codon of MESSENGER RNA is called anticodon, located in the MIDDLE loop of tRNA MOLECULE.

Correct answer is (b) cytoplasm

Explanation: MESSENGER RNAs (MRNAS) are PRESENT in the cytoplasm and are attached to RIBOSOMES where they are translated.

The correct choice is (a) RNA

For explanation: A messenger RNA is a complimentary copy of ONE of the two STRANDS of DNA that make up a gene. Transcription is the process of SYNTHESIS of RNA from a DNA TEMPLATE.

The correct answer is (a) pyrophosphatase

The best EXPLANATION: Reactions LEADING to the synthesis of nucleic acids must occur under IRREVERSIBLE conditions. These conditions are met during transcription with the AID of ENZYME called pyrophosphatase.

The CORRECT choice is (a) True

The BEST explanation: RNA is a mobile nucleic ACID that moves from the nucleus to the cytoplasm after transcription from the gene.

The correct answer is (a) GTP hydrolysis

For EXPLANATION I would say: The large RIBOSOMAL subunit joins the mRNA strand when initiator TRNA is bound and IF3 is DISPLACED. After a large subunit joins the complex, GTP is hydrolyzed to drive the conformational change in the ribosome so as to release IF2.

Right ANSWER is (b) AUG

The best explanation: INITIATION codon, AUG, is the SITE where the ribosome machinery attaches itself on the mRNA strand. ATTACHING to the initiation codon puts the ribosome in the PROPER reading frame of translation.

The correct OPTION is (C) protein synthesis

Easy explanation: Translation is the process of protein synthesis. Proteins are synthesized by DECODING the sequence of genes with the HELP of some adaptor MOLECULES and intermediaries such a transfer and messenger RNAs.

Correct choice is (a) gene knock-down

Explanation: When small interfering RNA are used in place of double STRANDED RNA, gene knock-down takes place. Subsequently there is INHIBITION of specific protein SYNTHESIS encoded by an mRNA having the same nucleotide sequence as that of INJECTED siRNA.

The correct answer is (b) fruit FLIES

Explanation: PIWI PROTEINS have been best studied in fruit flies, where their ABSENCE leads to defects in suppression of transposon movement in GERM cells and incapability of forming gametes.

Right OPTION is (a) nonsynonymous

To EXPLAIN I would say: Nonsynomous are the changes that cause a CHANGE in the amino acid sequence when there is a change in the NUCLEOTIDE sequence. Such changes affect the PHENOTYPE of an individual and are hence selected for or against in the process of natural selection.