What is the significance of glucose/lactate ratio monitoring in cell culture?

The correct answer is A: It indicates cell metabolic state and can predict culture performance. The glucose consumption rate and lactate production rate indicate metabolic efficiency. High lactate accumulation suggests metabolic stress and can inhibit cell growth.

What does 'mosaicism' refer to in the context of CRISPR gene editing outcomes?

The correct answer is B: The presence of mixed populations of edited and non-edited cells in the same organism. Mosaicism occurs when CRISPR editing is performed early in development, resulting in some cells being edited while others retain the original genotype, creating a mixed population.

In India, which regulatory body is responsible for approving genetically modified crops before their commercial release?

The correct answer is B: Genetic Engineering Appraisal Committee (GEAC). The Genetic Engineering Appraisal Committee (GEAC) is the competent authority under the Ministry of Environment, Forest and Climate Change that reviews and approves GM crops for environmental release and commercialization in India.

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

The correct answer is B: To direct Cas9 to the target DNA sequence. The sgRNA is a synthetic RNA molecule that guides the Cas9 endonuclease to the specific target DNA sequence through complementary base pairing, ensuring precise gene editing at the desired location.

In gene editing, CRISPR-Cas9 uses which type of guide molecule?

The correct answer is B: Guide RNA (sgRNA). CRISPR-Cas9 employs a single guide RNA (sgRNA) that directs Cas9 endonuclease to specific DNA target sequences for precise editing.

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Biotechnology

Genetic engineering, fermentation, cell biology

130 Q 3 Topics Take Mock Test

Difficulty: All Easy Medium Hard 41–50 of 130

Topics in Biotechnology

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

Q.41 Medium PCR & DNA Technology

In real-time PCR (qPCR), which fluorescent dye binds to double-stranded DNA and is commonly used for target quantification?

A SYBR Green

B Acridine orange

C Ethidium bromide

D Methylene blue

Correct Answer: A. SYBR Green

EXPLANATION

SYBR Green intercalates into double-stranded DNA and exhibits enhanced fluorescence, making it ideal for real-time monitoring of PCR amplification.

Test

Q.42 Medium PCR & DNA Technology

Which of the following statements about primer design for PCR is INCORRECT?

A Primers should be 18-25 bp long

B GC content should be 40-60%

C Primers should have high self-complementarity to ensure specificity

D Tm (melting temperature) of both primers should be similar

Correct Answer: C. Primers should have high self-complementarity to ensure specificity

EXPLANATION

High self-complementarity and primer-dimer formation should be avoided as they reduce PCR efficiency and specificity. Primers should have minimal secondary structure.

Test

Q.43 Medium PCR & DNA Technology

In whole genome amplification (WGA) using multiple displacement amplification (MDA), which enzyme is used?

A Taq polymerase

B Phi29 DNA polymerase

C Reverse transcriptase

D T4 DNA polymerase

Correct Answer: B. Phi29 DNA polymerase

EXPLANATION

Phi29 polymerase, from bacteriophage Phi29, has high processivity and 3' to 5' exonuclease activity, making it ideal for isothermal multiple displacement amplification of entire genomes.

Test

Q.44 Medium PCR & DNA Technology

What is the primary advantage of using nested PCR in pathogen detection?

A It reduces the number of PCR cycles required

B It increases specificity and sensitivity by using two rounds of amplification with inner and outer primer sets

C It eliminates primer-dimer formation

D It requires only one set of primers

Correct Answer: B. It increases specificity and sensitivity by using two rounds of amplification with inner and outer primer sets

EXPLANATION

Nested PCR uses outer primers for the first amplification round and inner primers for the second round, significantly improving specificity and sensitivity for detecting low-copy pathogens.

Test

Q.45 Medium PCR & DNA Technology

In the diagnosis of genetic disorders, why is allele-specific PCR (AS-PCR) preferred for detecting known mutations?

A It is faster than conventional sequencing

B It can specifically amplify the mutant allele while discriminating against the wild-type allele

C It requires no thermal cycling

D It eliminates the need for gel electrophoresis

Correct Answer: B. It can specifically amplify the mutant allele while discriminating against the wild-type allele

EXPLANATION

AS-PCR uses primers with mismatches at the 3' end that only allow amplification when perfectly matched to the target allele, providing rapid and cost-effective mutation detection.

Test

Q.46 Medium PCR & DNA Technology

What is the primary limitation of PCR when amplifying GC-rich sequences?

A Primers cannot bind to GC-rich regions

B Secondary structures form, reducing amplification efficiency

C Taq polymerase becomes inactive

D dNTPs are consumed too quickly

Correct Answer: B. Secondary structures form, reducing amplification efficiency

EXPLANATION

GC-rich sequences tend to form stable secondary structures (hairpins, loops), which can inhibit primer annealing and polymerase extension, reducing PCR efficiency.

Test

Q.47 Medium PCR & DNA Technology

In forensic applications, why are microsatellites (STRs) preferred over SNPs for individual identification?

A They are easier to sequence

B They show high polymorphism and can uniquely identify individuals

C They are located only on the Y chromosome

D They do not require PCR amplification

Correct Answer: B. They show high polymorphism and can uniquely identify individuals

EXPLANATION

STRs (Short Tandem Repeats) exhibit high variability between individuals due to differences in repeat numbers, making them ideal for forensic DNA profiling and paternity testing.

Test

Q.48 Medium PCR & DNA Technology

AFLP (Amplified Fragment Length Polymorphism) technology combines which two DNA techniques?

A PCR and DNA sequencing

B PCR and restriction enzyme digestion

C DNA hybridization and gel electrophoresis

D Cloning and Southern blotting

Correct Answer: B. PCR and restriction enzyme digestion

EXPLANATION

AFLP combines restriction enzyme digestion with PCR amplification of specific DNA fragments, generating polymorphic banding patterns useful for genetic mapping and strain differentiation.

Test

Q.49 Medium PCR & DNA Technology

What is the primary advantage of digital PCR (dPCR) over conventional qPCR?

A It requires fewer cycles

B It partitions samples into thousands of independent reactions for absolute quantification

C It eliminates the need for thermal cycling

D It uses lower annealing temperatures

Correct Answer: B. It partitions samples into thousands of independent reactions for absolute quantification

EXPLANATION

dPCR partitions the PCR reaction into numerous isolated compartments, allowing absolute quantification without requiring a standard curve, and provides higher precision than qPCR.

Test

Q.50 Medium PCR & DNA Technology

In reverse transcription PCR (RT-PCR), which enzyme is critical for the first step?

A Taq polymerase

B Reverse transcriptase

C DNA ligase

D Helicase

Correct Answer: B. Reverse transcriptase

EXPLANATION

Reverse transcriptase synthesizes complementary DNA (cDNA) from an RNA template in the first step of RT-PCR, enabling amplification of RNA targets like mRNA.

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