- The CRISPR-Cas9 system is primarily used for:
a) Gene cloning
b) Genome editing
c) DNA replication
d) RNA interference
Answer: b) Genome editing
Explanation:
CRISPR-Cas9 is a powerful tool used for precise genome editing, allowing scientists to cut and modify DNA at specific locations within an organism’s genome.
- Which of the following is used to separate DNA fragments by size?
a) PCR
b) Gel electrophoresis
c) Southern blotting
d) Transformation
Answer: b) Gel electrophoresis
Explanation:
Gel electrophoresis is a technique used to separate DNA fragments based on their size by applying an electric current to a gel matrix. Smaller fragments move faster through the gel than larger ones.
- Which of the following enzymes is used to join DNA fragments together?
a) DNA polymerase
b) RNA polymerase
c) DNA ligase
d) Reverse transcriptase
Answer: c) DNA ligase
Explanation:
DNA ligase is an enzyme that joins DNA fragments together by forming phosphodiester bonds between adjacent nucleotides. It is commonly used in molecular cloning to join foreign DNA into vectors.
- In which of the following processes is RNAi technology used?
a) Increasing gene expression
b) Silencing gene expression
c) DNA replication
d) Protein translation
Answer: b) Silencing gene expression
Explanation:
RNA interference (RNAi) technology is used to silence or reduce the expression of specific genes by degrading the corresponding mRNA, preventing the production of the target protein.
- Which of the following is a genetically modified crop developed to resist pests?
a) Flavr Savr tomato
b) Bt cotton
c) Golden Rice
d) Roundup Ready soybean
Answer: b) Bt cotton
Explanation:
Bt cotton is a genetically modified crop that produces insecticidal proteins from Bacillus thuringiensis, making it resistant to certain pests such as bollworms.
- Which of the following is NOT a benefit of genetically modified (GM) crops?
a) Increased crop yield
b) Reduced use of pesticides
c) Improved resistance to pests
d) Elimination of all health risks
Answer: d) Elimination of all health risks
Explanation:
While GM crops can offer benefits like increased yield, pest resistance, and reduced pesticide use, they do not eliminate all health risks, and there are still ongoing debates about their long-term safety.
- The enzyme used to cut DNA at specific sites is:
a) DNA ligase
b) Helicase
c) Restriction endonuclease
d) DNA polymerase
Answer: c) Restriction endonuclease
Explanation:
Restriction endonucleases (restriction enzymes) cut DNA at specific recognition sites, which is a key step in genetic engineering for creating recombinant DNA.
- Which of the following is a potential environmental risk of genetically modified organisms (GMOs)?
a) Improved crop yield
b) Crossbreeding with wild species
c) Reduced pesticide use
d) Increased resistance to drought
Answer: b) Crossbreeding with wild species
Explanation:
One potential environmental risk of GMOs is gene flow, where genetically modified traits may spread to wild species, potentially creating ecological imbalances or leading to the development of resistant “superweeds.”
- Which of the following organisms has been genetically modified to produce human insulin?
a) Escherichia coli
b) Saccharomyces cerevisiae
c) Rhizobium
d) Pseudomonas
Answer: a) Escherichia coli
Explanation:
Escherichia coli has been genetically engineered to produce human insulin by inserting the human insulin gene into the bacterial genome, allowing it to produce insulin for therapeutic use.
- Which of the following is used as a molecular marker in biotechnology?
a) Green Fluorescent Protein (GFP)
b) Restriction enzyme
c) DNA ligase
d) Polymerase Chain Reaction (PCR)
Answer: a) Green Fluorescent Protein (GFP)
Explanation:
GFP is commonly used as a molecular marker to visualize and track the expression of genes or the presence of specific cells in biological research, due to its fluorescent properties
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