1. What is the main goal of molecular cloning?
A) To amplify the entire genome
B) To isolate and amplify a specific gene or DNA fragment
C) To sequence the entire genome
D) To mutate a gene
Answer: B) To isolate and amplify a specific gene or DNA fragment
2. Which enzyme is primarily used to cut DNA at specific sequences in molecular cloning?
A) DNA polymerase
B) Ligase
C) Restriction endonuclease
D) RNA polymerase
Answer: C) Restriction endonuclease
3. What is the role of DNA ligase in molecular cloning?
A) To cleave DNA molecules
B) To join DNA fragments by forming phosphodiester bonds
C) To amplify DNA
D) To add methyl groups to DNA
Answer: B) To join DNA fragments by forming phosphodiester bonds
4. What does a plasmid vector do in molecular cloning?
A) Cuts the DNA into fragments
B) Introduces foreign DNA into host cells
C) Replicates itself independently of the host cell
D) Both B and C
Answer: D) Both B and C
5. What is a commonly used host organism for cloning plasmids?
A) E. coli
B) Saccharomyces cerevisiae
C) Bacillus subtilis
D) All of the above
Answer: A) E. coli
6. In molecular cloning, what is a recombinant DNA molecule?
A) A plasmid vector with an insert of foreign DNA
B) A DNA molecule that has been sequenced
C) A DNA molecule with only bacterial genes
D) A cloned gene
Answer: A) A plasmid vector with an insert of foreign DNA
7. Which of the following is used to select for transformed cells after cloning?
A) Antibiotic resistance gene
B) Restriction enzyme
C) Gel electrophoresis
D) PCR
Answer: A) Antibiotic resistance gene
8. What is the purpose of performing a colony PCR in molecular cloning?
A) To amplify a specific gene in bacteria
B) To identify transformed colonies containing the desired insert
C) To cut DNA into fragments
D) To sequence the plasmid
Answer: B) To identify transformed colonies containing the desired insert
9. What is the function of reverse transcription in molecular cloning?
A) To convert mRNA into cDNA
B) To copy DNA into RNA
C) To ligate DNA fragments
D) To amplify DNA fragments
Answer: A) To convert mRNA into cDNA
10. Which of the following methods is commonly used to insert recombinant DNA into host cells?
A) Transformation
B) Electroporation
C) Microinjection
D) All of the above
Answer: D) All of the above
11. What is the purpose of the “blue-white screening” technique in cloning?
A) To identify clones with specific gene insertions using a color change
B) To select for bacterial cells with plasmids
C) To amplify DNA in PCR
D) To induce bacterial cell transformation
Answer: A) To identify clones with specific gene insertions using a color change
12. Which type of DNA molecule is typically used as a vector in molecular cloning?
A) Circular DNA
B) Linear DNA
C) Both A and B
D) Only RNA
Answer: A) Circular DNA
13. What is the most common method for amplifying a gene of interest in molecular cloning?
A) Polymerase chain reaction (PCR)
B) Southern blotting
C) Gel electrophoresis
D) RNA interference
Answer: A) Polymerase chain reaction (PCR)
14. What does a restriction enzyme recognition site typically look like?
A) A palindromic sequence
B) A non-palindromic sequence
C) A repeating sequence
D) A highly methylated sequence
Answer: A) A palindromic sequence
15. What is a common application of molecular cloning?
A) Gene therapy
B) Protein production
C) Gene function studies
D) All of the above
Answer: D) All of the above
16. Which of the following vectors can be used for cloning large fragments of DNA?
A) Plasmids
B) Phage vectors
C) BACs (Bacterial Artificial Chromosomes)
D) Cosmid vectors
Answer: C) BACs (Bacterial Artificial Chromosomes)
17. Which process is used to introduce foreign DNA into plant cells for cloning?
A) Agrobacterium-mediated transformation
B) Electroporation
C) Heat shock
D) Microinjection
Answer: A) Agrobacterium-mediated transformation
18. What is a key characteristic of an expression vector in molecular cloning?
A) It contains a gene for antibiotic resistance
B) It is used for protein production
C) It can only be used in plant cells
D) It is always linear
Answer: B) It is used for protein production
19. In molecular cloning, what is an insert?
A) A plasmid vector
B) A foreign DNA fragment that is incorporated into the vector
C) A bacterial cell that contains a plasmid
D) An enzyme used for cutting DNA
Answer: B) A foreign DNA fragment that is incorporated into the vector
20. What is a potential disadvantage of using restriction enzymes in cloning?
A) They cannot cut the DNA at all
B) They can generate incomplete DNA fragments
C) They only cut certain sequences, limiting versatility
D) They require expensive reagents
Answer: C) They only cut certain sequences, limiting versatility
21. What is the purpose of using a bacterial expression system in molecular cloning?
A) To express a gene of interest for protein production
B) To select for transformed cells
C) To amplify DNA in the host cell
D) To induce mutation in the gene of interest
Answer: A) To express a gene of interest for protein production
22. Which of the following techniques is often used to detect the presence of a gene in molecular cloning experiments?
A) Northern blotting
B) Southern blotting
C) Western blotting
D) PCR
Answer: B) Southern blotting
23. Which of the following is the correct order for the steps in molecular cloning?
A) Transformation → Ligation → Amplification → Selection
B) Ligation → Transformation → Selection → Amplification
C) Amplification → Ligation → Selection → Transformation
D) Transformation → Selection → Amplification → Ligation
Answer: B) Ligation → Transformation → Selection → Amplification
24. What is a cosmids vector?
A) A plasmid that can carry a large DNA insert
B) A type of viral vector
C) A type of BAC vector
D) A combination of plasmid and phage vectors
Answer: D) A combination of plasmid and phage vectors
25. Which of the following is the best method for purifying recombinant proteins expressed in E. coli?
A) Dialysis
B) Affinity chromatography
C) Electrophoresis
D) Centrifugation
Answer: B) Affinity chromatography
26. What is a shuttle vector in cloning?
A) A vector that can replicate in two different organisms
B) A plasmid used to amplify DNA in yeast cells
C) A vector used only in bacterial cells
D) A plasmid that carries multiple resistance genes
Answer: A) A vector that can replicate in two different organisms
27. What is a transgenic organism in the context of molecular cloning?
A) An organism that contains foreign DNA integrated into its genome
B) An organism that has been cloned through somatic cell nuclear transfer
C) A bacterial cell used for DNA replication
D) An organism that undergoes gene silencing
Answer: A) An organism that contains foreign DNA integrated into its genome
28. Which of the following is a major limitation of molecular cloning?
A) High cost of reagents
B) Difficulty in isolating DNA fragments
C) Inefficiency of inserting large DNA fragments
D) Long duration of experiments
Answer: C) Inefficiency of inserting large DNA fragments
29. What is the primary reason for using a gene fusion approach in cloning?
A) To join two genes and study their interactions
B) To delete unwanted genes
C) To clone multiple genes at once
D) To express protein fragments
Answer: A) To join two genes and study their interactions
30. In molecular cloning, what is the purpose of a control experiment?
A) To increase the efficiency of gene cloning
B) To verify that the experiment was successful
C) To demonstrate the stability of the plasmid
D) To identify transformed colonies
Answer: B) To verify that the experiment was successful
These questions cover a range of topics related to molecular cloning, including techniques, vectors, methods of selection, and applications in research and biotechnology.
