Daily Olympiad: Biology - Biotechnology [20260512]

Challenge yourself with today's NEET practice! This test covers 'Biotechnology' for Biology (NEET - 12). Level: Hard | Duration: 45 mins.

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1. Which of the following vectors is most suitable for transferring large DNA fragments (>30 kb) into mammalian cells for transgenic applications?

Solution
Correct: C
BAC (Bacterial Artificial Chromosome) vectors can carry 100-300 kb of DNA fragments with low copy numbers, making them ideal for transferring large genomic DNA for transgenic studies. Cosmids have lower capacity (~45 kb) and are less efficient in mammalian systems. Plasmid vectors like pUC18 and yeast 2-micron plasmids are limited to small DNA fragments.

2. During recombinant DNA technology, which enzyme is essential for creating sticky ends in DNA to allow ligation with a vector containing complementary overhangs?

Solution
Correct: B
Restriction endonucleases like EcoRI create complementary sticky ends by cleaving DNA at specific palindromic sequences. DNA ligase joins the vector and insert DNA. Reverse transcriptase synthesizes cDNA from RNA, and DNA polymerase extends nucleotide sequences in PCR.

3. In CRISPR-Cas9 genome editing, what is the primary role of the single-guide RNA (sgRNA)?

Solution
Correct: B
The sgRNA forms a complex with Cas9 to direct it to the specific genomic target site. Methylation and replication are distinct processes, while non-specific degradation is not a CRISPR function. The Cas9 protein creates a double-strand break at the sgRNA-targeted location.

4. Which biotechnology technique employs a reverse transcriptase step followed by PCR amplification to quantify gene expression levels?

Solution
Correct: C
RT-PCR uses reverse transcriptase to convert mRNA into cDNA, which is then amplified via PCR to measure gene expression. Conventional PCR works with DNA, and qPCR measures quantification in real-time using fluorescent dyes.

5. What is the primary advantage of using Agrobacterium tumefaciens in plant genetic engineering?

Solution
Correct: B
Agrobacterium tumefaciens naturally transfers its T-DNA from the Ti plasmid into plant genomes, making it a powerful plant transformation tool. Other options do not relate to the bacterium's role in biotechnology applications.

6. In DNA fingerprinting, which technique is used to visualize specific DNA bands after restriction enzyme digestion and gel electrophoresis?

Solution
Correct: C
Southern blotting detects DNA fragments after restriction digestion and gel electrophoresis using labeled DNA probes. Western blots analyze proteins, Northern blots detect RNA, and Eastern blotting is used for post-translational modifications.

7. Which of the following is a critical ethical debate associated with human gene therapy using viral vectors?

Solution
Correct: B
Germline modifications via viral vectors raise ethical concerns because changes are heritable and could have unforeseen consequences across generations. Other options are technical risks but not central ethical issues in current gene therapy applications.

8. In the production of insulin via recombinant DNA technology, E. coli cells are transformed with a human insulin gene cloned behind a ______ promoter.

Solution
Correct: A
The lac promoter is inducible by lactose or IPTG and is used to control expression of the recombinant insulin gene in E. coli. Other promoters are either constitutive (GAPDH) or related to different regulatory systems (trp, beta-galactosidase).

9. Which of the following statements about Bt crops is NOT true?

Solution
Correct: B
Bt crops reduce chemical insecticide use by producing their own insecticidal toxins. The other statements correctly describe Bt technology's mechanisms and challenges, including specificity to larvae and the need for resistance management.