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Which of the following correctly describes the function and application of the Klenow fragment in genetic engineering?

• The Klenow fragment is a thermostable enzyme used in PCR due to its resistance to heat denaturation and synthesizes DNA from an RNA template.

• The Klenow fragment attaches to a single-stranded region or nick in double-stranded DNA, synthesizing a new strand while degrading the existing one, used in PCR.

• The Klenow fragment is a modified version of DNA Polymerase I that lacks nuclease activity, used for synthesizing complementary DNA strands without degrading the DNA, commonly used in DNA sequencing.

• The Klenow fragment is an enzyme from certain viruses that synthesizes DNA from an RNA template, crucial for cDNA cloning.

Which of the following statements correctly describes the application of Taq DNA polymerase in genetic engineering?

• Taq DNA polymerase synthesizes DNA from an RNA template, crucial for cDNA cloning.

• Taq DNA polymerase attaches to a single-stranded region or nick in double-stranded DNA, synthesizing a new strand while degrading the existing one.

• Taq DNA polymerase synthesizes complementary DNA strands without degrading the DNA, commonly used in DNA sequencing.

• Taq DNA polymerase is a thermostable enzyme used in PCR due to its resistance to heat denaturation.

Which of the following enzymes is responsible for removing the phosphate group present at the 5′ terminus of a DNA molecule?

• Polynucleotide kinase

• Alkaline phosphatase

• Terminal deoxynucleotidyl transferase

• Taq DNA polymerase

Which of the following statements correctly describes the functions of the enzymes polynucleotide kinase and terminal deoxynucleotidyl transferase?

• Polynucleotide kinase removes phosphate groups from the 5′ terminus, while terminal deoxynucleotidyl transferase adds one or more deoxyribonucleotides onto the 3′ terminus of a DNA molecule.

• Polynucleotide kinase adds phosphate groups to the 3′ terminus, while terminal deoxynucleotidyl transferase adds one or more deoxyribonucleotides onto the 5′ terminus of a DNA molecule.

• Polynucleotide kinase adds phosphate groups onto free 5′ termini, while terminal deoxynucleotidyl transferase adds one or more deoxyribonucleotides onto the 3′ terminus of a DNA molecule.

• Polynucleotide kinase removes phosphate groups from the 3′ terminus, while terminal deoxynucleotidyl transferase adds one or more deoxyribonucleotides onto the 5′ terminus of a DNA molecule.

Which of the following is used to make cells competent for DNA binding in traditional treatments?

• Sodium chloride (NaCl)

• Calcium chloride (CaCl2)

• Potassium chloride (KCl)

• Magnesium chloride (MgCl2)

Which of the following statements correctly describes the effects of CaCl2 treatment and heat shock on making cells competent and facilitating DNA uptake?

• CaCl2 treatment enhances DNA uptake into the cell, while heat shock improves DNA binding to the cell exterior.

• CaCl2 treatment causes DNA to precipitate inside the cell, and heat shock helps in binding the DNA to the cell surface

• CaCl2 treatment enhances DNA binding to the cell exterior but does not facilitate DNA uptake, while heat shock stimulates the actual uptake of DNA into the competent cells.

• CaCl2 treatment alone is sufficient for DNA uptake, and heat shock is not necessary.

What is the effect of inserting DNA at the BamHI site in pBR322?

• It disrupts the ampicillin resistance gene, making recombinant pBR322 molecules ampS tetR (sensitive to ampicillin, resistant to tetracycline).

• It disrupts both the ampicillin and tetracycline resistance genes, making recombinant pBR322 molecules ampS tetS (sensitive to both antibiotics).

• It disrupts the tetracycline resistance gene, making recombinant pBR322 molecules ampR tetS (resistant to ampicillin, sensitive to tetracycline).

• It has no effect on antibiotic resistance, leaving recombinant pBR322 molecules ampR tetR (resistant to both antibiotics).

Which of the following correctly describes the identification of recombinant pBR322 colonies during screening?

• Colonies that grow on ampicillin medium contain recombinant pBR322 (ampRtetS, recombinants), while those that do not grow contain non-recombinant pBR322 (ampRtetR, non-recombinants).

• Colonies that do not grow on ampicillin medium contain recombinant pBR322 (ampRtetS, recombinants), while those that grow contain non-recombinant pBR322 (ampRtetR, non-recombinants).

• Colonies that grow on tetracycline medium contain non-recombinant pBR322 (ampRtetR, non-recombinants), while those that do not grow contain recombinant pBR322 (ampRtetS, recombinants).

• Colonies that do not grow on tetracycline medium contain non-recombinant pBR322 (ampRtetR, non-recombinants), while those that grow contain recombinant pBR322 (ampRtetS, recombinants).

What is the correct order of steps in screening for recombinants using pBR322?

• Transformation and plating on ampicillin medium, replica plating onto tetracycline medium, incubation and identification of colonies

• Transformation and plating on tetracycline medium, incubation and identification of colonies, replica plating onto ampicillin medium

• Incubation and identification of colonies, transformation and plating on ampicillin medium, replica plating onto tetracycline medium

• Replica plating onto tetracycline medium, transformation and plating on ampicillin medium, incubation and identification of colonies

What is the correct order of steps in screening for recombinants using the pUC8 vector and the lacZ′ gene?

• Transformation and plating on tetracycline agar, replica plating onto ampicillin agar, observing colony color

• Identification using X-gal, transformation and plating on ampicillin agar, observing colony color

• Transformation and plating on ampicillin agar, replica plating onto tetracycline agar, identification using X-gal

• Transformation and plating on ampicillin agar, induction using X-gal, observing colony color