CMH Lahore Medical & Dental Entry Biology: Biotechnology MCQs

CMH Lahore Medical & Dental Entry Biology: Biotechnology MCQs — sample questions

1. Question 1

   Q1. What is the primary purpose of using restriction endonucleases in genetic engineering?

   • A) To synthesize new DNA strands
   • B) To amplify DNA sequences
   • C) To cut DNA at specific recognition sites
   • D) To ligate DNA fragments

   Answer: To cut DNA at specific recognition sites

   Explanation: Restriction endonucleases cut DNA at specific sequences, creating compatible ends for cloning; they don't synthesize or ligate DNA.

2. Question 2

   Q2. A scientist wants to introduce a gene for pest resistance into a crop plant. Which vector is commonly used?

   • A) Bacteriophage
   • B) Ti plasmid
   • C) Retrovirus
   • D) Cosmid

   Answer: Ti plasmid

   Explanation: Ti plasmid is used for plant transformation; bacteriophage and cosmid are used in bacteria, retrovirus in animals.

3. Question 3

   Q3. What is the role of DNA ligase in cloning?

   • A) To cut DNA at specific sites
   • B) To synthesize complementary DNA strands
   • C) To join DNA fragments together
   • D) To degrade unwanted DNA

   Answer: To join DNA fragments together

   Explanation: DNA ligase seals gaps between DNA fragments; it doesn't cut, synthesize, or degrade DNA.

4. Question 4

   Q4. Which technique is used to amplify a specific DNA sequence?

   • A) Gel electrophoresis
   • B) Polymerase Chain Reaction (PCR)
   • C) DNA sequencing
   • D) Cloning

   Answer: Polymerase Chain Reaction (PCR)

   Explanation: PCR amplifies specific DNA sequences; gel electrophoresis separates DNA, sequencing determines order, cloning makes copies.

5. Question 5

   Q5. What is the function of a selectable marker in a cloning vector?

   • A) To identify the insert size
   • B) To facilitate cloning of large DNA fragments
   • C) To select cells that have taken up the vector
   • D) To enhance expression of the insert

   Answer: To select cells that have taken up the vector

   Explanation: Selectable markers allow identification of cells containing the vector; they don't directly affect insert size or expression.

6. Question 6

   Q6. A researcher is studying the expression of a gene using a reporter gene. What is the typical function of a reporter gene?

   • A) To produce a toxic protein
   • B) To enhance the expression of the gene of interest
   • C) To indicate the activity of the promoter
   • D) To silence the gene of interest

   Answer: To indicate the activity of the promoter

   Explanation: Reporter genes indicate promoter activity; they don't produce toxins, enhance expression, or silence genes directly.

7. Question 7

   Q7. Which of the following is an application of biotechnology in medicine?

   • A) Production of biofuels
   • B) Development of genetically modified crops
   • C) Production of recombinant vaccines
   • D) Bioremediation

   Answer: Production of recombinant vaccines

   Explanation: Recombinant vaccines are a medical application; biofuels, GM crops, and bioremediation are industrial/agricultural/environmental applications.

8. Question 8

   Q8. What is the purpose of using a cDNA library?

   • A) To store genomic DNA fragments
   • B) To clone genes based on their expression
   • C) To sequence entire genomes
   • D) To amplify specific DNA sequences

   Answer: To clone genes based on their expression

   Explanation: cDNA libraries represent expressed genes; they don't store genomic DNA, sequence genomes, or amplify specific sequences directly.

9. Question 9

   Q9. In genetic engineering, what is the term for the process of introducing foreign DNA into a host cell?

   • A) Transformation
   • B) Transduction
   • C) Transfection
   • D) Conjugation

   Answer: Transformation

   Explanation: Transformation refers to direct DNA uptake; transduction involves viruses, transfection is used for animal cells, conjugation is bacterial cell-to-cell transfer.

10. Question 10

    Q10. What is the main advantage of using embryonic stem cells in biotechnology?

    • A) They are easily available
    • B) They can differentiate into any cell type
    • C) They are less likely to cause immune rejection
    • D) They can be cultured indefinitely

    Answer: They can differentiate into any cell type

    Explanation: Embryonic stem cells are pluripotent; they can become any cell type, unlike adult stem cells which are multipotent.

11. Question 11

    Q11. Which enzyme is responsible for synthesizing cDNA from mRNA?

    • A) DNA polymerase
    • B) Reverse transcriptase
    • C) RNA polymerase
    • D) Taq polymerase

    Answer: Reverse transcriptase

    Explanation: Reverse transcriptase synthesizes cDNA from RNA; DNA polymerase synthesizes DNA from DNA, RNA polymerase transcribes DNA to RNA.

12. Question 12

    Q12. A scientist is using gel electrophoresis to separate DNA fragments. What is the basis of separation?

    • A) Size and charge
    • B) Size only
    • C) Charge only
    • D) Sequence

    Answer: Size and charge

    Explanation: DNA separation is based on size (length) and charge; DNA is negatively charged, so size is the main variable.

13. Question 13

    Q13. What is the role of Taq polymerase in PCR?

    • A) To synthesize primers
    • B) To ligate DNA fragments
    • C) To amplify DNA sequences
    • D) To degrade DNA

    Answer: To amplify DNA sequences

    Explanation: Taq polymerase amplifies DNA; it doesn't synthesize primers, ligate DNA, or degrade DNA.

14. Question 14

    Q14. Which vector is commonly used to clone large DNA fragments?

    • A) Plasmid
    • B) Bacteriophage
    • C) Cosmid
    • D) YAC (Yeast Artificial Chromosome)

    Answer: YAC (Yeast Artificial Chromosome)

    Explanation: YACs can hold very large DNA inserts; cosmids hold up to 40 kb, plasmids and bacteriophages hold smaller fragments.

15. Question 15

    Q15. What is the primary purpose of using bioinformatics tools in biotechnology?

    • A) To analyze genomic data
    • B) To amplify DNA sequences
    • C) To clone genes
    • D) To express proteins

    Answer: To analyze genomic data

    Explanation: Bioinformatics tools analyze genomic and proteomic data; they don't directly amplify, clone, or express genes/proteins.

16. Question 16

    Q16. In gene therapy, what is the goal of using viral vectors?

    • A) To deliver healthy copies of a gene to cells
    • B) To induce an immune response
    • C) To diagnose genetic disorders
    • D) To produce recombinant proteins

    Answer: To deliver healthy copies of a gene to cells

    Explanation: Viral vectors deliver therapeutic genes to cells; they don't primarily induce immunity, diagnose disorders, or produce proteins.

17. Question 17

    Q17. What is the term for the process of analyzing the protein products of genes?

    • A) Genomics
    • B) Transcriptomics
    • C) Proteomics
    • D) Metabolomics

    Answer: Proteomics

    Explanation: Proteomics studies protein products; genomics studies genes, transcriptomics studies RNA, metabolomics studies metabolic products.

18. Question 18

    Q18. Which of the following is a benefit of using genetically modified crops?

    • A) Increased water requirement
    • B) Reduced pesticide use
    • C) Decreased nutritional value
    • D) Increased susceptibility to pests

    Answer: Reduced pesticide use

    Explanation: GM crops can reduce pesticide use through pest resistance; they don't inherently increase water needs or reduce nutrition.

19. Question 19

    Q19. What is the purpose of DNA sequencing?

    • A) To amplify DNA sequences
    • B) To clone genes
    • C) To determine the order of nucleotides
    • D) To express proteins

    Answer: To determine the order of nucleotides

    Explanation: DNA sequencing determines nucleotide order; it doesn't amplify, clone, or directly lead to protein expression.

20. Question 20

    Q20. A gene editing technique that allows for precise modifications to the genome is known as?

    • A) CRISPR-Cas9
    • B) PCR
    • C) Cloning
    • D) DNA sequencing

    Answer: CRISPR-Cas9

    Explanation: CRISPR-Cas9 enables precise genome editing; PCR amplifies DNA, cloning makes copies, sequencing determines order.