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				This section includes 61 Mcqs, each offering curated multiple-choice questions to sharpen your Genetic Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. | Choose the incorrect statement for cre-lox excision. | 
| A. | The chromosomal copy of the target gene replaces the target gene flanked by loxP sites | 
| B. | The second step is supply of Cre recombinase | 
| C. | Integration of cre takes place under a controllable promoter followed by induction of the promoter | 
| D. | Induction results in expression of cre, recombination along loxP sites and excision of the sequence between | 
| Answer» B. The second step is supply of Cre recombinase | |
| 2. | Excision of DNA flanked by loxP sequences is also known as _________ | 
| A. | subtle excision | 
| B. | croxing | 
| C. | floxing | 
| D. | sequence specific excision | 
| Answer» D. sequence specific excision | |
| 3. | Down regulation of expression of endogenous genes by transformation with constructs that would generate sense RNA, rather than anti-sense RNA is known as ___________ | 
| A. | suppression | 
| B. | co-suppression | 
| C. | multisuppression | 
| D. | anti-suppression | 
| Answer» C. multisuppression | |
| 4. | In some organisms, presence of double stranded RNAs leads to breakdown of corresponding single stranded mRNA. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» B. False | |
| 5. | The ________ protein of bacteriophage P1 mediates site-specific recombination at a 34 bp sequence, loxP. | 
| A. | cre recombinase | 
| B. | gene II | 
| C. | gene IV | 
| D. | gene VIII | 
| Answer» B. gene II | |
| 6. | Hepatitis delta virus capable of self cleavage. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» B. False | |
| 7. | siRNAs can either be introduced directly or by microinjection. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» B. False | |
| 8. | Double stranded RNA is cleaved by a nuclease called as Dicer and small fragments are generated known as ___________ | 
| A. | short interfering RNAs | 
| B. | long interfering RNAs | 
| C. | short interspersed RNAs | 
| D. | long interspersed RNAs | 
| Answer» B. long interfering RNAs | |
| 9. | DNA _________ is also a method for gene silencing through short RNAs. | 
| A. | acetylation | 
| B. | phosphorylation | 
| C. | methylation | 
| D. | acylation | 
| Answer» D. acylation | |
| 10. | RNA molecule with catalytic activity is termed as________ | 
| A. | ribosomes | 
| B. | catalytic RNA | 
| C. | reactive RNA | 
| D. | ribozyme | 
| Answer» E. | |
| 11. | Choose the correct statement for self cleavage reaction. | 
| A. | It is nucleophilic attack reaction by 2’ hydroxyl of RNA | 
| B. | It is nucleophilic attack reaction by 3’ hydroxyl of RNA | 
| C. | It is nucleophilic attack reaction by 2’ hydroxyl of DNA | 
| D. | It is nucleophilic attack reaction by 3’ hydroxyl of DNA | 
| Answer» B. It is nucleophilic attack reaction by 3’ hydroxyl of RNA | |
| 12. | The process of RNA inactivation by siRNAs is termed as ___________ | 
| A. | RNA silencing | 
| B. | RNA interference | 
| C. | Short RNA inactivation | 
| D. | RNA disfunction | 
| Answer» C. Short RNA inactivation | |
| 13. | Cre can be introduced by crossing it with a strain containing the gene or by infection with virus containing it. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» B. False | |
| 14. | Self cleavage reaction can take place in? | 
| A. | DNA | 
| B. | RNA | 
| C. | Both DNA and RNA | 
| D. | Can take place in both but is preferred in DNA | 
| Answer» C. Both DNA and RNA | |
| 15. | Introduction into host organism can also be done by using a DNA construct, which when transcribed, generates an RNA which is _________ | 
| A. | circular | 
| B. | linear | 
| C. | double stranded | 
| D. | self-complementary | 
| Answer» E. | |
| 16. | The ability to control the expression of cre allows controlling what? | 
| A. | recombination | 
| B. | replication | 
| C. | excision | 
| D. | packaging | 
| Answer» D. packaging | |
| 17. | How much effect is there on the surrounding genes by the loxP sequence which is left after recombination has taken place? | 
| A. | Little effect | 
| B. | No effect | 
| C. | Huge effect | 
| D. | It depends on the nature of the surrounding gene | 
| Answer» C. Huge effect | |
| 18. | Once second strand synthesis is carried out, it is introduced into the host. Host is having which mutation? | 
| A. | mutS mutation | 
| B. | mutD mutation | 
| C. | mutE mutation | 
| D. | mutG mutation | 
| Answer» B. mutD mutation | |
| 19. | Choose the incorrect statement for the methodology of selection of molecules with mutant sequences. | 
| A. | A vector is used which is having antibiotic resistance gene | 
| B. | Apart from antibiotic resistance gene, a second antibiotic resistance gene is also present | 
| C. | There are two mutagenic primers which are used | 
| D. | The second strand synthesis is carried out by only one primer | 
| Answer» E. | |
| 20. | In a phosphothiorate nucleotide, oxygen atom is replaced by with atom? | 
| A. | Magnesium | 
| B. | Calcium | 
| C. | Sodium | 
| D. | Sulphur | 
| Answer» E. | |
| 21. | Replication by first strand leads to the formation of mutated molecules and functional antibiotic resistant gene. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» C. May be True or False | |
| 22. | For the selection of the molecules having mutated sequence, which of the statement is true? | 
| A. | It is suitable for methods which are PCR based | 
| B. | It is suitable for methods which are not PCR based | 
| C. | It is suitable for both PCR and not PCR based | 
| D. | Selection of molecules with the mutant sequence is not possible | 
| Answer» C. It is suitable for both PCR and not PCR based | |
| 23. | A megaprimer method is a ____ stage approach and uses _____ oligonucleotide primers. | 
| A. | two, two | 
| B. | two, three | 
| C. | one, two | 
| D. | one, three | 
| Answer» C. one, two | |
| 24. | Sometimes mutagenesis is carried out with the help of primers. Choose the correct statement with respect to it. | 
| A. | Double stranded circular molecule is used as a template | 
| B. | Mutation is introduced into one of flanking primers | 
| C. | Single stranded circular molecule is used as a template | 
| D. | After amplification, mutation is introduced into one strand | 
| Answer» B. Mutation is introduced into one of flanking primers | |
| 25. | PCR using the mutagenic primer and one of the flanking primers is used to carry out amplification and generates a product corresponding to the part of the gene. It is called as megaprimer. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» B. False | |
| 26. | If PCR is used to introduce random mutations rather than specific mutations, it is called as ___________ | 
| A. | mutagenic PCR | 
| B. | error-prone PCR | 
| C. | random PCR | 
| D. | general PCR | 
| Answer» C. random PCR | |
| 27. | It is easier to subclone a restriction fragment if it belongs to? | 
| A. | small gene | 
| B. | large gene | 
| C. | prokaryotic organism | 
| D. | eukaryotic organism | 
| Answer» C. prokaryotic organism | |
| 28. | If mixed oligonucleotides are used, it is regarded as ______________ | 
| A. | mixed mutagenesis | 
| B. | multiple mutagenesis | 
| C. | cassette mutagenesis | 
| D. | polymutagenesis | 
| Answer» D. polymutagenesis | |
| 29. | Once the double stranded molecule with the mutation is introduced into E. coli for replication, how many types of molecules are produced? | 
| A. | 1 | 
| B. | 2 | 
| C. | 3 | 
| D. | 4 | 
| Answer» C. 3 | |
| 30. | Several different mutations can be induced at one site. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» B. False | |
| 31. | How many sites can be mutated at a time? | 
| A. | 1 | 
| B. | 2 | 
| C. | 3 | 
| D. | Many | 
| Answer» E. | |
| 32. | Bisulphite ions are used to deaminate ________ residues in _______ DNA. | 
| A. | C, double stranded | 
| B. | C, single stranded | 
| C. | U, double stranded | 
| D. | U, single stranded | 
| Answer» C. U, double stranded | |
| 33. | Which of the following statement is incorrect for the synthesis of the second strand? | 
| A. | The oligonucleotide is acting as a primer for the synthesis of the second strand | 
| B. | DNA polymerase and dNTPs are added for synthesis | 
| C. | The polymerase should have 5’-3’ exonuclease activity | 
| D. | A polymerase having 5’-3’ exonuclease activity would degrade the primer that carries the mutant sequence | 
| Answer» D. A polymerase having 5’-3’ exonuclease activity would degrade the primer that carries the mutant sequence | |
| 34. | For mutagenesis without PCR, which of the following can be used as a template? | 
| A. | Single stranded DNA | 
| B. | Double stranded DNA | 
| C. | Circular DNA | 
| D. | Both single and double stranded DNA | 
| Answer» E. | |
| 35. | An oligonucleotide is synthesized which contains the mutation and the rest is _______ to the template DNA. | 
| A. | complementary | 
| B. | non-complementary | 
| C. | can either be complementary or non-complementary | 
| D. | not related | 
| Answer» B. non-complementary | |
| 36. | If the template is double stranded, they need to be separated before annealing of oligonucleotide. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» B. False | |
| 37. | If methods are based on cellular processes that lead to inactivation of gene expression by affecting the RNA, then it is called as ___________ | 
| A. | transcriptional | 
| B. | pre-transcriptional | 
| C. | post-transcriptional | 
| D. | translational | 
| Answer» D. translational | |
| 38. | If the target organism contains more than one copy of the gene, what is the effect on these copies? | 
| A. | Only copy is disrupted | 
| B. | All the copies are disrupted | 
| C. | It is difficult to ensure that all the copies are disrupted | 
| D. | Only a specified number of copies are disrupted | 
| Answer» D. Only a specified number of copies are disrupted | |
| 39. | Choose the incorrect statement for the method based on antisense RNA. | 
| A. | RNA is synthesized complementary to the sequence of the gene which is to be inactivated | 
| B. | It is achieved by placing a DNA sequence which encodes RNA complementary to the RNA to be inactivated | 
| C. | Expression of the endogenous gene is diminished | 
| D. | This method is preferred over gene disruption has gene inactivation can be achieved completely | 
| Answer» E. | |
| 40. | The method of post transcriptional gene silencing is particularly useful in ___________ | 
| A. | plants | 
| B. | animals | 
| C. | insects | 
| D. | microorganisms | 
| Answer» B. animals | |
| 41. | If ______ gene is there, the double crossover may leave ________ in the chromosome. | 
| A. | linear, functional copy | 
| B. | circular, functional copy | 
| C. | linear, a non-functional copy | 
| D. | circular, a non-functional copy | 
| Answer» C. linear, a non-functional copy | |
| 42. | The disrupted gene is excised from the vector and is inserted into the target organism. The excised gene should be in which form? | 
| A. | Circular | 
| B. | Supercoiled | 
| C. | Either supercoiled or circular | 
| D. | Linear | 
| Answer» E. | |
| 43. | The gene to be disrupted is cloned and a selectable marker is inserted. What should be the effect of selectable marker? | 
| A. | It should have no effect on target gene | 
| B. | It should make the target gene non-functional | 
| C. | There is no restriction; it can be either functional or non-functional | 
| D. | It should improvise the chances of survival of the target gene | 
| Answer» C. There is no restriction; it can be either functional or non-functional | |
| 44. | Stable acquisition of the marker can take place only if a double crossover over the flanking sequence and their chromosomal counterparts causes the marker’s integration into the chromosome. | 
| A. | True | 
| B. | False | 
| C. | May be True or False | 
| D. | Can't say | 
| Answer» B. False | |
| 45. | The principle of gene disruption is ________ to replace the endogenous chromosomal copy of a gene with __________ | 
| A. | homologous recombination, inactivated gene | 
| B. | reciprocal translocation, inactivated gene | 
| C. | homologous recombination, activated gene | 
| D. | reciprocal translocation, activated gene | 
| Answer» B. reciprocal translocation, inactivated gene | |
| 46. | How can mutant strains be produced? | 
| A. | In systematic mutagenesis programmes | 
| B. | In individual organisms | 
| C. | Both by individual organisms and systematic mutagenesis programmes | 
| D. | Apart from these two, other methods are also used | 
| Answer» D. Apart from these two, other methods are also used | |
| 47. | DpnI cuts ________ strands. | 
| A. | methylated | 
| B. | non-methylated | 
| C. | phosphorylated | 
| D. | non-phosphorylated | 
| Answer» B. non-methylated | |
| 48. | What is the function of ung gene? | 
| A. | It is responsible for deamination of cytosine | 
| B. | It is responsible for deamination of uracil | 
| C. | It is responsible for removal of uracil | 
| D. | It is responsible for removal of cytosine | 
| Answer» D. It is responsible for removal of cytosine | |
| 49. | It is often useful to inactivate endogenous genes in an organism. It might be helpful in finding out _________ role of the wild type gene. | 
| A. | biological | 
| B. | chemical | 
| C. | physiological | 
| D. | anatomical | 
| Answer» D. anatomical | |
| 50. | The minor change in amino acid sequence can lead to _______ effect on three dimensional structure and there _____ in the primary sequence. | 
| A. | huge, may be no change | 
| B. | no, may be huge change | 
| C. | very less, is very less change | 
| D. | huge, would be huge change | 
| Answer» B. no, may be huge change | |