Consider a scenario where a genetic engineer develops a drought-resistant crop by introducing an aquaporin gene. Which of the following would be the most appropriate long-term assessment of this GM crop's environmental impact?

The correct answer is B: Conduct multi-generational studies on non-target organisms and ecosystem services. Comprehensive environmental impact assessment requires multi-generational studies examining effects on biodiversity, soil health, water systems, and non-target organisms. Short-term yield data alone is insufficient for determining ecological safety.

In droplet digital PCR (ddPCR), how does partitioning of the sample improve quantification accuracy compared to conventional qPCR?

The correct answer is B: Provides absolute quantification by partitioning into thousands of droplets for independent amplification. ddPCR partitions the sample into thousands of water-in-oil emulsion droplets, allowing independent amplification and enabling absolute quantification without standard curves.

Which of the following represents the correct sequence in scaling up cell culture from laboratory to industrial bioreactor?

The correct answer is A: Flask → 10L bioreactor → 100L bioreactor → 1000L bioreactor. Scale-up follows a logical progression from small (flask) to larger volumes, with each step validated for maintaining cell viability, growth rate, and product quality.

What is the primary disadvantage of using animal serum in cell culture for biopharmaceutical production?

The correct answer is B: It is expensive, variable between batches, and raises ethical concerns. Animal serum is costly, batch-to-batch variability is high, regulatory concerns exist, and it complicates downstream processing. Industries are shifting to serum-free media.

Which technique would be most suitable for introducing multiple genes simultaneously into a plant cell?

The correct answer is B: Gene stacking or pyramiding using multiple constructs. Gene stacking or pyramiding involves incorporating multiple transgenes into a single organism, useful for combining multiple desired traits like herbicide resistance and pest resistance.

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Biotechnology

Genetic engineering, fermentation, cell biology

130 Q 3 Topics Take Mock Test

Difficulty: All Easy Medium Hard 81–90 of 130

Topics in Biotechnology

All Genetic Engineering 100 PCR & DNA Technology 100 Cell Culture 60

Q.81 Medium Genetic Engineering

During the development of a genetically modified organism (GMO), scientists use selectable marker genes. If an antibiotic resistance gene is used as a marker, which scenario would indicate successful transformation?

A Transformed cells survive on media containing the antibiotic; non-transformed cells die

B Non-transformed cells survive on media containing the antibiotic; transformed cells die

C Both transformed and non-transformed cells survive equally on antibiotic media

D Neither transformed nor non-transformed cells survive on antibiotic media

Correct Answer: A. Transformed cells survive on media containing the antibiotic; non-transformed cells die

EXPLANATION

Selectable marker genes confer resistance to specific antibiotics or toxins. When the transformation vector carries an antibiotic resistance gene, only cells that successfully incorporated the vector will express the resistance gene and survive on antibiotic-containing media. Non-transformed cells lack this gene and are eliminated.

Test

Q.82 Medium Genetic Engineering

In CRISPR-Cas9 gene editing technology, what is the specific role of the single guide RNA (sgRNA)?

A It synthesizes new DNA strands after Cas9 cuts the DNA

B It directs the Cas9 nuclease to the target DNA sequence by complementary base pairing

C It repairs double-strand breaks created by Cas9

D It prevents off-target cutting by blocking non-specific sites

Correct Answer: B. It directs the Cas9 nuclease to the target DNA sequence by complementary base pairing

EXPLANATION

The sgRNA contains a CRISPR RNA (crRNA) and trans-activating CRISPR RNA (tracrRNA) combined into a single molecule. It guides the Cas9 nuclease to the target DNA sequence through Watson-Crick base pairing, ensuring specificity of the cut.

Test

Q.83 Medium Genetic Engineering

A biotechnology company in India has developed a transgenic crop that produces its own Bt toxin for pest resistance. Which of the following best explains the mechanism by which this toxin controls insect pests?

A It inhibits protein synthesis in insect gut cells by breaking down peptide bonds

B It creates pores in the insect midgut epithelial membrane, leading to cell lysis and death

C It interferes with the insect nervous system by blocking neurotransmitter receptors

D It reduces the insect's ability to metabolize plant sugars

Correct Answer: B. It creates pores in the insect midgut epithelial membrane, leading to cell lysis and death

EXPLANATION

Bt toxin (Cry proteins) forms pores in the alkaline midgut of target insects, causing cell lysis and disruption of the intestinal epithelium. This is specific to lepidopteran, coleopteran, and dipteran insects with appropriate pH and protease conditions.

Test

Q.84 Medium Genetic Engineering

In the context of RNA interference (RNAi), what is the role of the RISC complex?

A To amplify target mRNA

B To recognize and cleave complementary mRNA with guide RNA

C To transcribe DNA

D To synthesize new RNA

Correct Answer: B. To recognize and cleave complementary mRNA with guide RNA

EXPLANATION

The RNA-Induced Silencing Complex (RISC) uses small RNA molecules (siRNA or miRNA) as guides to recognize and degrade complementary mRNA sequences, leading to gene silencing.

Test

Q.85 Medium Genetic Engineering

Which chromosomal engineering technique is used to determine the order and orientation of genes on a chromosome?

A Gene sequencing

B Physical mapping or chromosomal mapping

C Protein synthesis

D Transcriptomics

Correct Answer: B. Physical mapping or chromosomal mapping

EXPLANATION

Physical and chromosomal mapping techniques such as FISH (Fluorescence In Situ Hybridization), optical mapping, and chromosome walking determine gene order and positions on chromosomes.

Test

Q.86 Medium Genetic Engineering

What is the significance of the TATA box in eukaryotic gene expression?

A It codes for a regulatory protein

B It is the binding site for RNA polymerase II and transcription factors

C It marks the start codon

D It promotes protein synthesis

Correct Answer: B. It is the binding site for RNA polymerase II and transcription factors

EXPLANATION

The TATA box is a promoter element located ~25-30 bp upstream of the transcription start site. It binds transcription factor IID (TFIID) and directs RNA polymerase II to the correct position.

Test

Q.87 Medium Genetic Engineering

In gene therapy, what is the primary advantage of using adeno-associated virus (AAV) as a vector?

A Large packaging capacity (>50 kb)

B Low immunogenicity and ability to transduce both dividing and non-dividing cells

C Integration into host chromosome

D Ability to carry multiple genes simultaneously

Correct Answer: B. Low immunogenicity and ability to transduce both dividing and non-dividing cells

EXPLANATION

AAVs are small viruses with low immunogenicity, can transduce non-dividing cells, and are relatively safe for clinical use. However, they have limited packaging capacity (~4.7 kb).

Test

Q.88 Medium Genetic Engineering

Which of the following is an example of a selectable marker gene used in genetic engineering?

A Antibiotic resistance gene (e.g., ampicillin resistance)

B Green fluorescent protein (GFP) gene

C LacZ gene

D Reporter genes only

Correct Answer: A. Antibiotic resistance gene (e.g., ampicillin resistance)

EXPLANATION

Selectable marker genes confer resistance to antibiotics or toxins, allowing researchers to identify and select transformed cells. Antibiotic resistance genes are the most common examples.

Test

Q.89 Medium Genetic Engineering

In transcription factor-based gene regulation, which domain is responsible for DNA binding?

A Transactivation domain

B DNA-binding domain

C Nuclear localization signal

D Signal peptide

Correct Answer: B. DNA-binding domain

EXPLANATION

The DNA-binding domain (DBD) of transcription factors contains specific structures (zinc fingers, helix-turn-helix, leucine zippers) that recognize and bind to specific DNA sequences.

Test

Q.90 Medium Genetic Engineering

What is the PAM (Protospacer Adjacent Motif) sequence requirement in Streptococcus pyogenes CRISPR-Cas9?

A AAAA

B NGG (where N is any nucleotide)

C GCGC

D TTAA

Correct Answer: B. NGG (where N is any nucleotide)

EXPLANATION

S. pyogenes Cas9 recognizes the PAM sequence NGG (usually GG) immediately downstream of the target sequence, which is essential for proper target site recognition.

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