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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Which of the following phenomena was experimentally proved by Meselson and Stahl?A. DNA is genetic materialB. Central dogmaC. TransformationD. Semi conservative DNA replication |
| Answer» Correct Answer - D | |
| 152. |
Which of the following phenomena was experimentally proved by Meselson and Stahl?A. TransformationB. TransductionC. Semi-conservative DNA replicationD. Central dogma |
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Answer» Correct Answer - c (c) : The Meselson and Stahl experiment was an experiment to prove that DNA replication was semi-subsequently and it was first shown in Escherichia coli and subsequently in higher organisms, such as plants and human cells. Semi-conservative replication means that when the double stranded DNA helix was replicated, each pf the two double stranded DNA helices consisted of one strand coming from the parental helix and one is newly synthesised. |
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| 153. |
What does 'lac' refer to in what we call the lac operon ?A. Lac insectB. The number , 1,00,000C. LactoseD. Lactase |
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Answer» Correct Answer - C Lac operon refers to the DNA sequence in the genome of the bacterium E. coli encodong enzymes involved in lactose uptake and metabolism. |
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| 154. |
Why is the enzyme cellulase needed for isolating genetic material from plant cells and not from the animal cells? |
| Answer» Because plant cells have walls made up of cellulose and cellulase enzyme degrades cellulose and helps in the isolation of genetic material. | |
| 155. |
The codon AUG isA. OchreB. AmberC. Initiation codonD. Termination codon |
| Answer» Correct Answer - C | |
| 156. |
Mention two functions of the codon AUG. |
| Answer» AUG has dual function, it codes for methionine (met.) and it acts as.initiator codon. | |
| 157. |
The initiating codon AUG specifies forA. valineB. leucineC. lysineD. methionine |
| Answer» Correct Answer - D | |
| 158. |
The initiation codon in protein synthesis isA. AUGB. GUGC. metD. AUG or GUG |
| Answer» Correct Answer - D | |
| 159. |
Assertion : A change in nitrogen bass at the third position of a codon causes change in the expression of the codon. Reason : A codon is mostly read by all the three nitrogen bases.A. If both assertion and reason are true and reason is the correct explanation of assertionB. If both assertion and reason are true but reason is not the correct explanation of assertionC. If assertion is true but reason is falseD. if both assertion and reason are false. |
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Answer» Correct Answer - d (d) : According to the Wobble hypothesis , only the first two position of a triplet codon on mRNA have a precise pairing with the bases of the tRNA anticodon . The pairing of the third position bases of the codon may be ambiguous and varies according to the nucleotide present in this position. Thus ,a single tRNA type is able to recognise two or more codons differing only in the third base. The same is called wobble position. |
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| 160. |
The arrangement of three bases in the genetic code signifies a specificA. ProteinB. Amino acidC. PlasmidD. Nucleic acid |
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Answer» Correct Answer - b b) Amino acids is coded by a group of three bases called as condon. |
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| 161. |
Which of the following group of codons code for amino acid serneA. CUU, CUC, CUA and CUGB. UAU , UAC , UGU and UGCC. UCU, UCC, UCA and UCGD. UGU ,UGC, UGA and UAG |
| Answer» Correct Answer - c | |
| 162. |
Refer to the given diagram. What does it represent ? A. Transcription in prokaryotesB. Transcription in eukaryotesC. Translation in prokaryotesD. Translation in eukaryotes |
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Answer» Correct Answer - b (b) : The given diagram represents post-transcriptional processing resulting in the formation of mRNA . Since, introns and exons are present m it is trsanscription in eukaryotes. |
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| 163. |
Polycistronic mesenger RNA (mRNA) usually occurs inA. bacteriaB. prokaryotesC. eukaryotesD. both a and b |
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Answer» Correct Answer - d (d) : When a particular gene codes for a mRAN strand it is said to be monocistronic or monogenic. When several genes (cistrons) are transcribed into a single mRNA molecule, it is described as polycistronic or polygenic. Prokaryotic mRNA are polycistronic. |
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| 164. |
mRNA iin prokaryotes is usuallyA. monocistronicB. polycistronicC. monokaryoticD. replicative |
| Answer» Correct Answer - B | |
| 165. |
In regulation of gene expression in prokaryotes Lactose acts as the suppreessor for gene expression Tryptophan acts as the inducer for gene expression Regulator gene is the one that produces the repressor moleculeA. A alone correctB. B alone correctC. C alone correctD. B and A are correct |
| Answer» Correct Answer - c | |
| 166. |
Read the statements regarding the lac operon and choose the correct option. 1. An inducer regulates the switching on and off of lac operon. 2. Repressor protein dissociates from operator region and prevents RNA polymerase from transcribing the operon. 3. In the presence of lactose, the repressor is activated by interaction with lactose. 4. RNA polymerase has access to the promoter and transcription proceeds only when the repressor is inactivated.A. 1 and 4 alone are correctB. 2 alone is correctC. 3 and 4 alone are correctD. 1 and 3 alone are correct |
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Answer» Correct Answer - A `**" "`Repressor protein associates from operator region and prevents RNA polymerase from transcribing he operon. `**" "`In the presence of lactose, the repressor is inactivated by interaction with lactose. |
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| 167. |
In prokaryotes, the predominant site (or primary step) of control of gene expression is atA. Control of rate of transcriptional initiation.B. Control of rate of translation initiation.C. Control of rate of initiation of replicationD. Processing level |
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Answer» Correct Answer - A In prokaryotes, control of the rate of transcriptional initiation is the predominant site for control of gene expression. |
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| 168. |
Assertion : The predominant site for control ofgene expression in prokaryotes is transcription initiation. Reason : The activity of RNA polymerase is regulated by accessory proteins, which affect recognition of start sites.A. If both assertion and reason are true and reason is the correct explanation of assertionB. If both assertion and reason are true but reason is not the correct explanation of assertionC. If assertion is true but reason is falseD. if both assertion and reason are false. |
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Answer» Correct Answer - a (a) In prokaryotes, control of the rate of transcriptional initiation is the predominant site for control of gene expression. In a transcription unit, the activity of RNA polymerase at a given promoter , isin turn turn regulated by interaction with accessory porteins, Which affect its ability its ability to recognise start sites. These regulatory proteins can act both positively (activators) and negatively (repressors). |
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| 169. |
RNA polymerase required for initiationA. Sigma subunitB. Beta-subunitC. RHO subunitD. Spliceosome |
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Answer» Correct Answer - A RNA polymerase requires sigma subunit for initiation. |
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| 170. |
Assertion. In bacteria the cpromosome is irregularly folded into a compact mass, the nucleoid or genophore of definite form. Reason. In bacteria there is no organised nucleus.A. If both A and R are true and R is the correct explanation of A.B. If both A and R are true but R is not the correct explanation of A.C. If A is true but R is false.D. If both A and R are false. |
| Answer» Correct Answer - A | |
| 171. |
All the terminator codons begin with the nucleotide of `:`A. GuanineB. UracilC. CytosineD. Adenine |
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Answer» Correct Answer - B All the terminator codons (UAA, UAG and UGA) begin with uracil. |
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| 172. |
Which of the following types of RNA molecule can be described as soluble, relatively small nd having a folded compact shapeA. rRNAB. tRNAC. mRNAD. Nucleolar RNA |
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Answer» Correct Answer - b b) t RNA molecules have been variously termed as soluble RNA or supernatant RNA or adapter RNA. |
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| 173. |
Which is soluble RNA :-A. hn RNAB. rRNAC. mRNAD. tRNA |
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Answer» Correct Answer - D `**` From the very beginning of the proposition of code, it was clear to Francis Crick that there has to be a mechanism to read the code and also to link it to the amino acids, because amino acids have no structural specialties to read the code uniquely. `**` He postulated the presence of an adapter molecule that would on one hand read the code and on other hand would bind to specific amino acids. `**` The tRNA, then called sRNA (soluble RNA), was known before the genetic code was postulated. |
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| 174. |
Nuclear DNA sends information for protein synthesis throughA. tRNAB. mRNAC. rRNAD. All of the above |
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Answer» Correct Answer - B Nuclear DNA sends information for protein synthesis through mRNA. |
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| 175. |
Supercoiled DNA can be traced inA. Prokaryotes and eukaryotesB. Eukaryotes onlyC. Prokaryotes onlyD. None of these |
| Answer» Correct Answer - a | |
| 176. |
Genetic information transfer nucleus to cytoplasm byA. DNAB. RNAC. LysosomeD. All |
| Answer» Correct Answer - b | |
| 177. |
The given flow chart represents the flow of genetic information between biomolecules. Identify the processes A,B,C and D and select the correct option. A. `{:(A,B,C,D),("Translation"," Transcription ","Replication","Reverse ),(,,,"Transcription"):}`B. `{:(A,B,C,D),("Replication"," Transcription ","Translation","Reverse ),(,,,"Transcription"):}`C. `{:(A,B,C,D),("Replication"," Transcription ","Reverse","Translation" ),(,,"Transcription",):}`D. `{:(A,B,C,D),("Replication"," Reverse ","Transcription","Translation" ),(,"Transription",,):}` |
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Answer» Correct Answer - c (c) : DNA replication refers to the porcess of formation of two similar copies of DNA using parental DNA as template. The expression of the genetic material accurs normally through the production of proteins. This involves two consecutive steps. These are transcription and translation. THe DNA codes for the production of massenger RNA (mRNA) during transcription. mRNA carries coded information to ribosomes. The ribosomes read this information and use it for protein synthesis. This process is called translation. Crick decribed this undirectional flow of information in 1958 as the central dogma of molecular biology. Many tumour viruses contain RNA as genetic material and replicate by first synthesising a complementary DNA. This process is called reverse transcription (teminism). It is carried out by an RNA-dependent DNA polymerase called reverse transcriptase. |
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| 178. |
Synthesis of DNA from RNA is explained byA. central dogma reverseB. reverse transcriptionC. teminismD. all of these. |
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Answer» Correct Answer - d (d) : DNA replication refers to the porcess of formation of two similar copies of DNA using parental DNA as template. The expression of the genetic material accurs normally through the production of proteins. This involves two consecutive steps. These are transcription and translation. THe DNA codes for the production of massenger RNA (mRNA) during transcription. mRNA carries coded information to ribosomes. The ribosomes read this information and use it for protein synthesis. This process is called translation. Crick decribed this undirectional flow of information in 1958 as the central dogma of molecular biology. Many tumour viruses contain RNA as genetic material and replicate by first synthesising a complementary DNA. This process is called reverse transcription (teminism). It is carried out by an RNA-dependent DNA polymerase called reverse transcriptase. |
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| 179. |
5-methyl uracil isA. Another name of thymineB. A purine baseC. A double ring structureD. Both A and C |
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Answer» Correct Answer - A 5-methyl uracil is another name of thymine |
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| 180. |
If the length of E. coli DNA is 1.36 mm, then how many base pairs are present in E. coil ?A. `3.6 xx 10^(4)`B. `3.6 xx 10^(6)`C. `4.0 xx 10^(6)`D. `4.6 xx 10^(6)` |
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Answer» Correct Answer - C No. of base pair `=("Total length")/("Length between 2 bases")` `=(1.36xx10^(-3))/(0.34xx10^(-9))=4xx10^(6)` |
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| 181. |
What does A and B represent in the given representation ? A. A-Ribonucleoside, B-DeocyribonucleosideB. A-Ribonucleotide, B-DeocyribonucleotideC. A-Nucleoside, B- NucleotideD. A-Nucleotide, B- Nucleoside |
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Answer» Correct Answer - c (c) : `"sugar" +"Nitrogenous base" rarr "Nucleoside sugar" +"Nitrogenous base" +"Phosphate" rarr "Nucleotide"` |
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| 182. |
Histone proteins areA. basic , negatively chargedB. basic , positively chargedC. acidic, positively chargedD. acidic, negatively charged. |
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Answer» Correct Answer - b (b) : In eukaryotes, DNA organisation is complex. There is a set of positively changed, basic porteins called histones. Histones are rich in the basic amino acid residues lysine and arginine. There are five types of histone proteins-`H_(1),H_(2)A,H_(2)B, H_(3) and H_(4)`. Four of them `(H_(2)A, H_(2)B, H_(3) and H_(4))` produce histone octamer called nu body or core of nucleosome . The negatively charged DNA is wrapped around the positively charged histone octamer to form nucleosome. DNA connecting two adjacent nucleosomes is called linker DNA which bears `H_(1)` histone proteins. |
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| 183. |
Select the incorrect statement.A. Two chains of DNA are coiled in right-handed fashion.B. In protein only right handed helices are observed.C. Right end of protein chain is reducing end while left end is non-reducing.D. Living state is the non-equilibrium steady state to be able to perform work. |
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Answer» Correct Answer - C Right end of polysaccharide chain is reducing end while left end is nor - reducing. |
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| 184. |
What does the given diagram represent ? A. NucleosomeB. SpliceosomeC. Histone complexD. Both (a) and (b) |
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Answer» Correct Answer - a (a) : In eukaryotes, DNA organisation is complex. There is a set of positively changed, basic porteins called histones. Histones are rich in the basic amino acid residues lysine and arginine. There are five types of histone proteins-`H_(1),H_(2)A,H_(2)B, H_(3) and H_(4)`. Four of them `(H_(2)A, H_(2)B, H_(3) and H_(4))` produce histone octamer called nu body or core of nucleosome . The negatively charged DNA is wrapped around the positively charged histone octamer to form nucleosome. DNA connecting two adjacent nucleosomes is called linker DNA which bears `H_(1)` histone proteins. |
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| 185. |
A typical nucleosome contains :A. 100 bp of DNA helixB. 200 bp of ONA helixC. 300 bp of DNA helixD. 400 bp of DNA helix |
| Answer» Correct Answer - B | |
| 186. |
Refer the given figure of nucleosome and select the option that correctly identifies the parts A,B and C. A. `{:(A,B,C,),("DNA"," Histone octamer ",H_(1)"histone", ),(,,,):}`B. `{:(A,B,C,),("Histone octamer", H_(1)"histone",DNA, ),(,,,):}`C. `{:(A,B,C,),("Histone octamer",DNA, H_(1)"histone", ),(,,,):}`D. `{:(A,B,C,),(DNA, H_(1)"histone","Histone octamer" ,),(,,,):}` |
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Answer» Correct Answer - c (c) : In eukaryotes, DNA organisation is complex. There is a set of positively changed, basic porteins called histones. Histones are rich in the basic amino acid residues lysine and arginine. There are five types of histone proteins-`H_(1),H_(2)A,H_(2)B, H_(3) and H_(4)`. Four of them `(H_(2)A, H_(2)B, H_(3) and H_(4))` produce histone octamer called nu body or core of nucleosome . The negatively charged DNA is wrapped around the positively charged histone octamer to form nucleosome. DNA connecting two adjacent nucleosomes is called linker DNA which bears `H_(1)` histone proteins. |
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| 187. |
Codons that specify same amino acids are calledA. synonymsB. autonymsC. synergesticD. antagonistic |
| Answer» Correct Answer - A | |
| 188. |
Reverse transcriptase is `:`A. RNA dependent RNA polymeraseB. DNA dependant RNA polymeraseC. DNA dependent RNA polymeraseD. RNA dependent DNA polymerase |
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Answer» Correct Answer - D Reverse transcriptase is RNA dependent DNA polymerase . H Temin and D Baltimore discovered reverse transcription . Reverse transcriptase has modified central dogma of molecular biology as RNA `to` DNA `to` RNA `to` Protein. |
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| 189. |
A 340 Å long segment of DNA molecules has 20 thymine nitrogenous bases, what will be the number of guanine nitrogen b ases in the same segmentA. 10B. 40C. 80D. 160 |
| Answer» Correct Answer - c | |
| 190. |
In DNA nitrogen bases are joined to each other byA. H-bondsB. Peptide bondsC. Glycosidic bondsD. Phosphodiester bonds |
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Answer» Correct Answer - A In DNA nitrogen bases are joined to each other by H-bonds. |
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| 191. |
Genes are packed in bacterial chromosome byA. histonesB. basic proteinC. acidic proteinD. actin |
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Answer» Correct Answer - B Bacteria are prokaryotic organisms . Polyamines (bacic proteins ) like spermidine and cadaverine (instead of histones) are associated with DNA packagineg in bacteria. |
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| 192. |
Eukaryotic genes may not function properly when cloned into bacterial cell because ofA. inability to excise intronsB. destruction by native endonucleasesC. destruction by native endonucleasesD. failure of promoter to be recognised by bacterial RNA polymerase |
| Answer» Correct Answer - D | |
| 193. |
In pyrimidines, N is at _____position in its noe ring.A. 1,3B. 7,9C. 1D. 1 & 9 |
| Answer» Correct Answer - A | |
| 194. |
Which organic molecule, other than nucleic acids , can replicate ? |
| Answer» Prion, and infectious protien that may increase in number by converting related protine to more prions. Prions cause degenerative diseases , e.g., scrapie in sheep, the "mad-cow diase " which recently badly affected the British beef industry , and Creutzfeldt -akob (CJ) disease in human. American scientist Stanley Prusiner got Nobel Prize for his work on prion. | |
| 195. |
Which organic molecule, other than proteins, act as biocatalysts? |
| Answer» Thomans Cech and his co-workers discovered in 1980s that RNA molecules are important catalysts in modern cells. This finding disproved the long held view that protins ( enzymes ) alone serve as biological catalysts. | |
| 196. |
Which is not part of transcription unit ?A. PromoterB. TerminatorC. Structural geneD. Inducer |
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Answer» Correct Answer - D `**" "`The segment of DNA that takes part in transcription is called transcription unit. `**" "`A transcription unit in DNA is defined primarily by the three regions in the DNA : (i) A Promoter (ii) The Structural gene (iii) A Terminator |
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| 197. |
ssDNA is genetic material is found inA. `phixx174` coliphageB. `T_(2)` coliphageC. influenza virusD. wound Tumor virus |
| Answer» Correct Answer - A | |
| 198. |
PCR and RFLP are employed inA. DNA sequencingB. Genetic fingerprintingC. Study of enzymesD. Genetic transformation |
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Answer» Correct Answer - B PCR abd RFLP are employed in genetic engineering. |
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| 199. |
DNA nucleotides are attached byA. Hydrogen bondB. Covalent bondC. Van der waal bondD. Electrovalent Bond |
| Answer» Correct Answer - a | |
| 200. |
In Operon concept, regulator gene functions asA. RepressorB. RegulatorC. InhibitorD. All of these |
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Answer» Correct Answer - a a) Regualar gene produces a repressor that binds to operator gene and stops the working of the latter. |
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