1. What is transformation in recombinant DNA technology?
A.
The uptake of foreign DNA by a host cell
B.
The cutting of DNA by restriction enzymes
C.
The joining of DNA fragments
D.
The multiplication of bacterial cells
Correct Answer:
The uptake of foreign DNA by a host cell
Explanation:
Transformation is the process by which a host cell takes up foreign or recombinant DNA.
2. Which type of cells are commonly used for transformation in recombinant DNA technology?
A.
Competent bacterial cells
B.
Dead bacterial cells
C.
Red blood cells
D.
Mature nerve cells
Correct Answer:
Competent bacterial cells
Explanation:
Competent bacterial cells are specially treated to make them capable of taking up foreign DNA.
3. What is the main purpose of making bacterial cells competent?
A.
To enable them to take up foreign DNA
B.
To stop them from dividing
C.
To destroy their chromosomes
D.
To produce restriction enzymes
Correct Answer:
To enable them to take up foreign DNA
Explanation:
Competence allows bacterial cells to receive and take up recombinant DNA during transformation.
4. Which chemical is commonly used to make bacterial cells competent for transformation?
A.
Calcium chloride
B.
Sodium chloride
C.
Glucose
D.
Ethanol
Correct Answer:
Calcium chloride
Explanation:
Calcium chloride treatment helps bacterial cells take up foreign DNA by altering the cell surface.
5. In the heat-shock method, what happens to competent bacterial cells?
A.
They are briefly exposed to a higher temperature
B.
They are exposed to ultraviolet radiation
C.
They are frozen permanently
D.
They are treated with restriction enzymes
Correct Answer:
They are briefly exposed to a higher temperature
Explanation:
A brief heat shock helps competent bacterial cells take up the recombinant DNA present in the surrounding solution.
6. Which method uses an electric pulse to introduce foreign DNA into a host cell?
A.
Electroporation
B.
Centrifugation
C.
Dialysis
D.
Chromatography
Correct Answer:
Electroporation
Explanation:
Electroporation uses a short electric pulse to temporarily increase the permeability of the cell membrane, allowing DNA to enter.
7. What type of DNA is introduced into a bacterial host during transformation?
A.
Recombinant DNA
B.
Only RNA
C.
Protein molecules
D.
Lipids
Correct Answer:
Recombinant DNA
Explanation:
During transformation, recombinant DNA, usually carried by a vector, is introduced into the bacterial host cell.
8. What is the immediate result when a bacterial cell successfully takes up a recombinant plasmid?
A.
The plasmid becomes present inside the bacterial cell
B.
The bacterial cell loses its membrane
C.
The plasmid is converted into protein
D.
The bacterial cell stops containing DNA
Correct Answer:
The plasmid becomes present inside the bacterial cell
Explanation:
Successful transformation places the recombinant plasmid inside the host bacterial cell, where it can be maintained and replicated.
9. Why are transformed bacterial cells often grown on selective medium?
A.
To identify cells that have received the vector
B.
To remove all bacterial DNA
C.
To prevent cells from absorbing nutrients
D.
To cut the plasmid into fragments
Correct Answer:
To identify cells that have received the vector
Explanation:
A selective medium allows cells carrying the vector's selectable marker to survive or grow, helping identify transformed cells.
10. Which structure commonly carries foreign DNA into a bacterial host during transformation?
A.
Plasmid vector
B.
Ribosome
C.
Cell wall
D.
Mitochondrion
Correct Answer:
Plasmid vector
Explanation:
A plasmid vector carries the foreign DNA and introduces it into the bacterial host during transformation.
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