Screening of Recombinant Cell

Q. Plasmid pBR322 has Pst I restriction enzyme site within gene amp^R that confers ampicillin resistance. If this enzyme is used for inserting a gene for ß-galactoside production and the recombinant plasmid is inserted in an E. coli strain

Q. The colonies of recombinant bacteria appear white in contrast to blue colonies of non-recombinant bacteria because of:

1. Insertional inactivation of alpha-galactosidase in non-recombinant bacteria
2. Inactivation of glycosidase enzyme in recombinant bacteria
3. Non-recombinant bacteria containing beta-galactosidase
4. Insertional inactivation of alpha-galactosidase in recombinant bacteria

Q. Read the given statements and select the correct option.
Statement-1: In insertional inactivation, blue colour produced by bacterial colonies indicates that the plasmid does not have an insert into the bacterial genome.
Statement-2: Presence of insert results into insertional inactivation of beta- galactosidase enzyme and the colonies do not produce any colour.

1. Both statements 1 and 2 are incorrect
2. Both statements 1 and 2 are correct and statement 2 is correct explanation of statement 1
3. Both statements 1 and 2 are correct but statement 2 is not correct explanation of statement 1
4. Statement 1 is correct and statement 2 is incorrect

Q.

What is insertional inactivation?

Q. If a recombinant DNA bearing gene for ampicillin resistance is transferred into E. coli cells and the host cells are spread on agar plates containing ampicillin, then

1. both transformed and untransformed recipient cells will die
2. both transformed and untransformed recipient cells will grow
3. transformed recipient cells will grow and untransformed recipient cells will die
4. transformed recipient cells will grow and untransformed recipient cells will grow

Q. Which of the following was the first restriction endonuclease to be isolated and characterised?

1. EcoR Ⅰ
2. Hind Ⅲ
3. BamH Ⅰ
4. Hind Ⅱ

Q. Hybridoma technology has been successfully used in

1. Production of alcohol in bulk
2. Synthesis of monoclonal antibodies
3. Synthesis of haemoglobin
4. Production of somatic hybrids

Q.

Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable market?

Q. Which among the following statement is incorrect?

1. Hind Ⅱ was the first restriction endonuclease to be isolated and characterised
2. The Roman number at the end of restriction enzymes indicates the strain number of the bacteria
3. Endonuclease binds to the specific nucleotide sequence in the DNA and cuts the sugar-phosphate backbone
4. Today more than 900 restriction enzymes have been isolated from over 230 strains of bacteria

Q. Antibiotic resistance gene present on Bam HI site of a E. coli cloning vector is -

1. Chloramphenicol resistance
2. Tetracycline resistance
3. Kanamycin resistance
4. Streptomycin resistance

Q.

The colonies of recombination bacteria appear white in contrast to the blue colonies of non-recombinant bacteria because of?

1. inactivation of glycosidase enzyme in recombinant bacteria

2. insertional inactivation of alpha galactosidase in recombinant bacteria

3. insertional inactivation of alpha galactosidase in non-recombinant bacteria

4. non-recombinant bacteria containing beta galactosidase

Q. Match the following:
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{A. Vector}& \text{i. Molecular scissors}\\ \text{B. DNA ligase}& \text{ii. Carrier}\\ \text{C. Host}& \text{iii. Molecular glue}\\ \text{D. Restriction enzymes}& \text{iv. Bacterial cell}\end{array}$

1. A - ii, B - i, C - iv, D - iii
2. A - ii, B - i, C - iii, D - iv
3. A - ii, B - iii, C - iv, D - i
4. A - i, B - ii, C - iii, D - iv

Q. For the isolation of DNA, different lysing enzymes are used for breaking different cell types and constituents. Which among the following is not used while isolating DNA from bacteria?

1. Protease
2. Lysozyme
3. Ribonuclease
4. Deoxyribonuclease

Q. Tom was trying to isolate a human gene (X) responsible for producing an enzyme (Y). His target was to synthesize Y on a large scale for commercial utility. Mention the correct order of the steps that he needs to perform in order to isolate his gene of interest.
I. Obtaining cell sample from desired tissue
II. Separation of desired DNA by gel electrophoresis
III. Cell lysis
IV. Amplification of desired DNA sequence by PCR
V. Isolation of genomic DNA
VI. Identification of desired band, cutting and elution of DNA from gel

1. I → III → V → IV → II → VI
2. I → III → IV → V → II → VI
3. I → II → V → VI → III → IV
4. I → III → V → II → IV → VI

Q. Match the following

Column Ⅰ	Column Ⅱ
A. Sticky ends	1. Recognition site
B. Exonuclease	2. Helps in hydrogen bond formation
C. Palindromic DNA sequence	3. Strain of the bacteria
D. ‘R’ in EcoRⅠ	4. Break the covalent bond

Choose the correct option

1. A-2, B-2, C-4, D-1
   
2. A-2, B-4, C-1, D-3
   
3. A-1, B-4, C-2, D-3
   
4. A-4, B-3, C-1, D-2
   

Q. With the help of DNA ligase, donor DNA fragment is joined. It is called

1. molecular cloning
2. tissue culture
3. protoplasmic fusion
4. splicing

Q. Which of the following is correct about nucleases?

1. It is a large class of enzymes consisting of exonucleases and endonucleases
2. Exonucleases remove nucleotide from only one end of the DNA
3. Endonucleases make specific cuts within the DNA by breaking ionic bonds
4. All of them recognise palindromic nucleotide sequences in the DNA

Q. Choose the correct option to indicate the techniques used for product purification during downstream processing of the recombinant gene product.
I. Chromatography
II. Heat shock
III. Centrifugation

1. I and II
2. II and III
3. I and III
4. Only I

Q. Describe the characteristics a cloning vector must possess.

Q. Each restriction endonuclease recognises a specific palindromic nucleotide sequence in the DNA. Explain.

Q. The lysate of cells scraped out of the buccal cavity was treated with all the macromolecule digesting enzymes except DNase. After purification, the resulting fraction of DNA was cut using enzymes. The technique used to separate the resulting fragments of DNA could be

I. gel electrophoresis
II. polymerase chain reaction
III. restriction digestion
IV. southern blotting

1. I and II
2. II and IV
3. only I
4. II, III and IV

Q. Assertion :Plasmids are found in all prokaryotic cells. Reason: $pBR322$ is a cloning vector that lacks antibiotic resistance genes.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. If a recombinant DNA bearing gene for ampicillin resistance is transferred into $E.coli$ cells and the host cells are spread on agar plates containing ampicillin, then

1. both transformed and untransformed recipient cells will die
2. both transformed and untransformed recipient cells will grow
3. transformed recipient cells will grow and untransformed recipient cells will die
4. transformed recipient cells will die and untransformed recipient cells will grow

Q. Match the following:
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{A. Vector}& \text{i. Molecular scissors}\\ \text{B. DNA ligase}& \text{ii. Carrier}\\ \text{C. Host}& \text{iii. Molecular glue}\\ \text{D. Restriction enzymes}& \text{iv. Bacterial cell}\end{array}$

1. A - ii, B - i, C - iv, D - iii
2. A - ii, B - i, C - iii, D - iv
3. A - ii, B - iii, C - iv, D - i
4. A - i, B - ii, C - iii, D - iv

Q. Bacterial colonies that have a foreign DNA fragment inserted in to the plasmid will appear white because:

1. Gal gene is active
2. X-gal can be cleaved by permease
3. X-gal can be cleaved by $\beta$- galactoxidase
4. Gal gene shows insertional inactivation due to insertion of foreign DNA

Q. The gene 'rop' present in pBR322 cloning vector, codes for

1. The proteins involved in the translation
2. The proteins involved in the replication of the plasmid
3. The proteins involved in the synthesis of ampicillin only
4. The proteins involved in the synthesis of tetracycline only

Q. In a plasmid vector, the number of sites for a restriction endonuclease is present

1. Only once
2. Any number
3. Restriction site not needed
4. Twice

Q. A scientist tried to transform bacteria with a plasmid containing the gene of interest inserted within the lacZ gene. Few of the bacteria took up the plasmid while many didn’t. He plated this mixture of bacteria on a medium containing X-gal. Choose the illustration which correctly represents the results he would have obtained based on blue-white screening.

Q. If a person obtains transformants by inserting a recombinant DNA within the coding sequence of enzyme -galactosidase, he will separate out recombinants from non-recombinants by which of the following observations?

1. Non-recombinant colonies do not produce any colour whereas recombinants give blue coloured colonies
2. Recombinant colonies do not produce any colour whereas non-recombinants give blue coloured colonies
3. Recombinants and non-recombinants both produce blue coloured colonies
4. No colonies are formed due to insertional inactivation

Q. The colonies of recombinant bacteria appear white in contrast to blue colonies of nonrecombinant bacteria because of

1. Insertional inactivation of $\alpha$-galactosidase in nonrecombinant bacteria
2. Insertional inactivation of $\alpha$-galactosidase in recombinant bacteria
3. Nonrecombinant bacteria contain beta galactosidase
4. Inactivation of glycosidase enzyme in recombinant bacteria