Recombinant Dna Technology — Part 1 MCQs with Explanations

The circular molecules will be amplified by the cells is the correct answer to “If bacterial cells are transformed with a mixture of linear and circular molecules resulting from a ligation reaction designed to produce a recombinant molecule”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Addition of excess glucose to the medium is the correct answer to “A recombinant protein is to be expressed under the control of the lac promoter and operator in a strain of E. coli having the genotype lacI + crp + . Even in the absence of inducer IPTG, low levels of expression of the recombinant protein are seen (leaky expression). Which one of the following should be done to minimize such leaky expression”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

[A] is false but [R] is true is the correct answer to “Determine the correctness or otherwise of the following Assertion [A] and the Reason [R] . Assertion [A]: Dam methylase protects E. coli DNA from phage endonucleases. Reason [R]: E. coli Dam methylase methylates the adenosine residue in the sequence "GATC".”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

P, R and S only is the correct answer to “The schematic of a plasmid with a gap in one of the strands is shown below: Which of the following enzyme(s) is/are required to fill the gap and generate a covalently closed circular plasmid? P. DNA ligase Q. Alkaline phosphatase R. DNA polymerase S. Polynucleotide kinase”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

P-4, Q-2, R-1, S-3 is the correct answer to “Match the following genetic elements with their functions. Genetic elements Functions P. neo R 1. Facilitates inducible expression of genes in eukaryotes. Q. SV40 2. Facilitates constitutive expression of genes in eukaryotes. R. LTR 3. Allows amplification of gene. S. S. dhfr. 4. Provides way of selecting eukaryotic cells, which have received foreign DNA.”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

50% is the correct answer to “cDNA made from the mRNA of an organism was used to make a cDNA library in a vector that allows the expression as a fusion with a reporter tag. What percentage of the cDNA clones is likely to give rise to correct gene products”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Gus gene is the correct answer to “Commonly used reporter gene in plant expression vectors is”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

2, 3, 4, 5, 6, 7, 8, and 10 is the correct answer to “EcoRI restriction sites on a 10kb DNA fragment are shown below Upon partial digestion, what are the lengths (in kb) of all the possible DNA fragments obtained”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Q, R is the correct answer to “What are the experimental steps needed for screening an expression library for clone encoding a protein X that has been isolated and purified? P. mRNA isolation Q. Antibody preparation R. Cloning into an appropriate vector S. Western blotting on transferred plaques”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Intraallelic complementation is the correct answer to “The basis for blue-white screening with pUC vectors is”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Exquisite specificity of T7 RNA polymerase to phage promoters is the correct answer to “Phage T7 promoter containing plasmids are used for over-expression of cloned genes because”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

The sequence context at the RB defines the direction of transfer is the correct answer to “Though the right border (RB) and left border (LB) of T-DNA are identical, the DNA transfer is specific for the DNA left of the RB (the T-DNA), rather than for the DNA left of the LB because”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

XmaIII (C/GGCGG) is the correct answer to “The restriction endonuclease Eco52I recognizes the sequence C/GGCGG and cuts between the first C and the first G, indicated by the slash. DNA cut by which of the following enzymes (given with their recognition sequences and cut sites) could be cloned into a plasmid digested with Eco52I”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Q, S is the correct answer to “Which of the following are commonly used as reporter genes? P. NPTgene Q. Luciferase gene R. CFTR gene S. GFP gene”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Opine biosynthesis genes are located within the T-DNA segment is the correct answer to “Which one of the following statements about Agrobacterium Ti plasmid is correct”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

P-4, Q-3, R-2, S-1 is the correct answer to “Match the items in Group I with Group II . Group I (Vectors) Group II (Maximum DNA packaging) P. λ phage 1. 35 - 45 kb Q. Bacterial Artificial Chromosomes (BACs) 2. 100 - 300 kb R. P1 derived Artificial Chromosomes (PACs) 3. ≤ 300 kb S. λ cosmid 4. 5 - 25 kb”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

0.55 is the correct answer to “A single base pair of DNA weighs 1.1 × 10 -21 grams. How many picomoles of a plasmid vector of length 2750 bp are contained in 1 μg of purified DNA”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

The plasmid contains the gene encoding β-lactamase is the correct answer to “Many plasmids have ampr marker. This implies”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Q, S is the correct answer to “Expression in poor amount and in inactive form of cDNA of a eukaryotic protein in Escherichia coli using its expression vector is due to P. The absence of capping mechanism of mRNA. Q. Codon bias. R. Absence of polyadenylation. S. Absence of proper glycosylation.”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Labeling 5' ends of DNA is the correct answer to “T4 polynucleotide kinase is used for”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Isoschizomers is the correct answer to “Restriction endonucleases which recognize and cut same recognition sequences are known as”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

25 base pairs is the correct answer to “The length of each boarder sequence in Ti plasmid is about”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

7.5 μM is the correct answer to “A DNA fragment of 4500 bp has to be tailed with dT residues by using dTTP and the enzyme 'terminal transferase' The stock solution of dTTP that is used as a substrate has concentration of 150 μM. Ten μL of this stock solution is added to a total volume of 200 μL reaction. What will be the concentration of dTTP in the reaction”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Insects is the correct answer to “Baculovirus expression system is used to express heterologous genes in”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

P-4, Q-1, R-2, S-3 is the correct answer to “A variety of genetic elements are used in the transgenic plant research. Match the genetic elements (Group I) with their corresponding source (Group II) . Group I Group II P. Ubiquitin1 promoter 1. Agrobacterium tumefaciens Q. Nos transcriptional terminator 2. Streptomyces hygroscopicus R. bar selection marker gene 3. Escherichia coli S. gus reporter gene 4. Zea mays”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Tumor inducing gene is the correct answer to “The essential component of Ti plasmid required for integration into plant genome is”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Bacillus subtilis is the correct answer to “The bacteria known to be naturally competent for transformation of DNA is”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

F plasmid is the correct answer to “BAC, which can be used to clone large DNA fragments, is derived from”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Vir gene is the correct answer to “Transfer of T-DNA from Ti plasmid into plant cell is mediated by”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Vancomycin is the correct answer to “Antibiotic resistance marker that cannot be used in a cloning vector in Gram negative bacteria is”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

The absence of splicing machinery is the correct answer to “A gene cannot be isolated from a human genomic DNA library by functional complementation in E. coli because of”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Viral thymidine kinase is the correct answer to “During a positive-negative selection process, transformed animal cells expressing . . . . . . . . are killed in presence of ganciclovir in the medium.”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Pancreas is the correct answer to “To isolate a gene coding for glucagon, the cDNA library as to be constructed using mRNA isolated from”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

ATGCCT is the correct answer to “Which one of the following cannot be a recognition sequence for a type II restriction enzyme”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

An antibiotic resistance marker is the correct answer to “To be a cloning vector, a plasmid does not require”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Border repeat sequences and vir genes is the correct answer to “Select the correct combination of genetic components that are essential for the transfer of T-DNA segment from Agrobacterium tumefaciens to plant cells.”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

4 labeled; 6 unlabeled is the correct answer to “A linear DNA fragment is 100% labeled at one end and has 3 restriction sites for EcoRI. If it is partially digested by EcoRI so that all possible fragments are produced, how many of these fragments will be labeled and how many will not be labeled”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

4.05 × 105 is the correct answer to “A cell has five molecules of a rare mRNA. Each cell contains 4 × 10 5 mRNA molecules. How many clones one will need to screen to have 99% probability of finding at least one recombinant cDNA of the rare mRNA, after making cDNA library from such cell”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

Alkaline phosphatase is the correct answer to “The enzymes that can be used in 5' end labeling of DNA are”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.

SalmIII (GG↓CC) is the correct answer to “The restriction endonuclease HaeIII recognizes the sequence GG ↓ CC and the point of cleavage is given by the arrow. If you want to clone a piece of DNA in a plasmid digested by HaeIII, what will be restriction enzyme of choice”. This question is standard in competitive examination syllabi for Recombinant Dna Technology.