Q.1 What is the primary purpose of a viral vector in gene therapy?
To synthesize proteins directly
To deliver therapeutic genes into target cells
To remove toxins from the bloodstream
To act as a vaccine booster
Explanation - Viral vectors are engineered viruses that carry therapeutic genes into patient cells, enabling the cells to produce a missing or defective protein.
Correct answer is: To deliver therapeutic genes into target cells
Q.2 Which type of nucleic acid is used in mRNA vaccines?
DNA
Messenger RNA (mRNA)
MicroRNA (miRNA)
Short interfering RNA (siRNA)
Explanation - mRNA vaccines use synthetic messenger RNA strands that encode the viral antigen, instructing cells to produce the antigen protein.
Correct answer is: Messenger RNA (mRNA)
Q.3 CRISPR-Cas9 is best described as:
A viral delivery system
A protein synthesis inhibitor
A gene editing tool
A type of antibody
Explanation - CRISPR-Cas9 is a programmable system that can cut DNA at specific locations, enabling precise gene editing.
Correct answer is: A gene editing tool
Q.4 Which of the following is a key safety concern in viral vector–based gene therapy?
Rapid degradation of the vector in the bloodstream
Immune responses causing inflammation
The vector's inability to replicate
Overproduction of the therapeutic protein
Explanation - Patients may develop strong immune reactions against the viral vector, leading to inflammation or vector clearance.
Correct answer is: Immune responses causing inflammation
Q.5 What is a major advantage of lipid nanoparticle (LNP) delivery systems for mRNA therapeutics?
They are inherently immunogenic
They allow non-viral systemic delivery
They require viral capsids for uptake
They can only target liver cells
Explanation - LNPs encapsulate mRNA, protecting it from degradation and enabling uptake by cells without using viruses.
Correct answer is: They allow non-viral systemic delivery
Q.6 Which of the following is NOT a typical target for gene therapy?
Cystic fibrosis
Sickle cell anemia
Common cold
Hemophilia B
Explanation - The common cold is caused by many viruses and lacks a single genetic defect suitable for gene therapy.
Correct answer is: Common cold
Q.7 Which nucleic acid–based drug can silence genes by degrading complementary mRNA?
Antisense oligonucleotide (ASO)
CRISPR-Cas9 guide RNA
mRNA vaccine
DNA plasmid
Explanation - ASOs bind to target mRNA and promote its degradation or block translation, thereby silencing gene expression.
Correct answer is: Antisense oligonucleotide (ASO)
Q.8 The first FDA‑approved gene therapy product for a disease was:
Luxturna (voretigene neparvovec)
Zolgensma (onasemnogene abeparvovec)
Spinraza (nusinersen)
Glybera (alipogene tiparvovec)
Explanation - Zolgensma, approved in 2019 for spinal muscular atrophy, was the first FDA‑approved viral vector gene therapy.
Correct answer is: Zolgensma (onasemnogene abeparvovec)
Q.9 Which of these is a primary difference between DNA‑based and RNA‑based gene therapies?
DNA therapies are always delivered via viruses
RNA therapies integrate permanently into the host genome
DNA therapies typically persist longer in cells
RNA therapies are inherently more stable than DNA
Explanation - DNA, once inside cells, can persist or integrate, providing long‑term expression, whereas RNA is transient.
Correct answer is: DNA therapies typically persist longer in cells
Q.10 What is a key regulatory hurdle for nucleic acid therapeutics?
Manufacturing at high temperature
Achieving high levels of viral contamination
Demonstrating consistent potency and purity
Ensuring the drug is non‑immunogenic
Explanation - Regulators require rigorous characterization of nucleic acid drugs to ensure safety and efficacy.
Correct answer is: Demonstrating consistent potency and purity
Q.11 In CRISPR gene editing, what is the role of the Cas9 protein?
To bind to mRNA and promote translation
To cut DNA at a targeted location
To encapsulate the guide RNA
To deliver the editing machinery into the nucleus
Explanation - Cas9 acts as a nuclease that cleaves DNA guided by the CRISPR RNA sequence.
Correct answer is: To cut DNA at a targeted location
Q.12 Which delivery method is most commonly used for in vitro transfection of plasmid DNA?
Electroporation
Passive diffusion
Surgical implantation
Intravenous infusion
Explanation - Electroporation applies an electric field to increase cell membrane permeability, facilitating DNA uptake.
Correct answer is: Electroporation
Q.13 What does the term 'off‑target effects' refer to in the context of gene editing?
Editing only the intended gene
Unintended changes to other genes or DNA sites
Targeting proteins outside the genome
Therapy affecting non‑human cells
Explanation - Off‑target effects are undesired edits that occur at genomic sites similar to the target, potentially causing harmful mutations.
Correct answer is: Unintended changes to other genes or DNA sites
Q.14 Which component of the CRISPR-Cas system is responsible for recognizing the target DNA sequence?
Cas9
Guide RNA (gRNA)
Protospacer adjacent motif (PAM)
DNA polymerase
Explanation - The guide RNA contains a sequence complementary to the target DNA, guiding Cas9 to the correct site.
Correct answer is: Guide RNA (gRNA)
Q.15 Which nucleic acid‑based therapy uses short RNA duplexes to induce RNA interference?
siRNA
mRNA
DNA plasmid
Adenoviral vector
Explanation - Short interfering RNA (siRNA) triggers degradation of target mRNA, silencing gene expression.
Correct answer is: siRNA
Q.16 Why is the liver often targeted in RNA‑based vaccine delivery?
It produces high levels of blood proteins
It is immune‑privileged
It has abundant Kupffer cells
It can quickly degrade nucleic acids
Explanation - The liver’s unique immune environment allows efficient uptake of LNPs and expression of the encoded protein.
Correct answer is: It is immune‑privileged
Q.17 Which of the following is NOT a typical step in developing an mRNA vaccine?
Designing the mRNA sequence
Formulating lipid nanoparticles
Inserting viral envelope proteins
Conducting clinical trials
Explanation - mRNA vaccines encode antigens; viral envelope proteins are not inserted into the mRNA itself.
Correct answer is: Inserting viral envelope proteins
Q.18 What is the main advantage of using non‑viral delivery systems over viral vectors?
Higher immunogenicity
Lower manufacturing cost
Better integration into the genome
Higher packaging capacity
Explanation - Non‑viral systems avoid complex viral production steps, reducing cost and potential immune responses.
Correct answer is: Lower manufacturing cost
Q.19 In gene therapy, the term 'transduction' refers to:
Cell division
Gene insertion into the nucleus
Delivery of genes via a viral vector
Deletion of a gene sequence
Explanation - Transduction describes the process by which viruses deliver genetic material into a host cell.
Correct answer is: Delivery of genes via a viral vector
Q.20 Which of these diseases has a FDA‑approved gene therapy targeting a single gene?
Alzheimer's disease
Duchenne muscular dystrophy
Cystic fibrosis
Type 2 diabetes
Explanation - Exon skipping therapies for CFTR gene mutations are approved as gene‑based treatments.
Correct answer is: Cystic fibrosis
Q.21 What does the acronym ‘CRISPR’ stand for?
Clustered Regularly Interspaced Short Palindromic Repeats
Cytosine Recombination Insertion Sequence Protein Receptor
Comprehensive RNA Integration System for Precise Repair
Controlled Recombination Insertion Sequence for Protein Replacement
Explanation - CRISPR refers to the natural bacterial defense system used for precise genome editing.
Correct answer is: Clustered Regularly Interspaced Short Palindromic Repeats
Q.22 Which of the following is a potential ethical concern with gene editing?
Increased drug stability
Unintended ecological impacts
Enhanced vaccine efficacy
Reduced manufacturing time
Explanation - Gene editing could unintentionally affect ecosystems if edited organisms escape containment.
Correct answer is: Unintended ecological impacts
Q.23 What is the primary function of a promoter in a plasmid DNA used for gene therapy?
To guide the plasmid into the nucleus
To initiate transcription of the therapeutic gene
To protect the plasmid from degradation
To serve as an antibiotic resistance marker
Explanation - Promoters are DNA sequences recognized by RNA polymerase to start transcription of downstream genes.
Correct answer is: To initiate transcription of the therapeutic gene
Q.24 Which of these is a major advantage of mRNA over DNA therapeutics?
Permanent integration into genome
Lower risk of insertional mutagenesis
Longer half‑life in blood
Higher immunogenicity
Explanation - mRNA stays in the cytoplasm and does not integrate into DNA, reducing mutagenesis risk.
Correct answer is: Lower risk of insertional mutagenesis
Q.25 Which technique is commonly used to verify successful gene insertion in a plasmid?
Polymerase chain reaction (PCR)
Western blotting
ELISA
Mass spectrometry
Explanation - PCR amplifies specific DNA sequences, confirming presence of the inserted gene.
Correct answer is: Polymerase chain reaction (PCR)
Q.26 What is a key advantage of using a lentiviral vector?
It infects non‑dividing cells
It has a smaller packaging size
It requires no promoter sequence
It is naturally immunogenic
Explanation - Lentiviruses can integrate into the genome of quiescent cells, enabling stable gene expression.
Correct answer is: It infects non‑dividing cells
Q.27 Which nucleic acid sequence is required for Cas9 recognition?
Protospacer adjacent motif (PAM)
Transcription start site (TSS)
Polyadenylation signal
Splice donor site
Explanation - The PAM sequence adjacent to the target DNA is essential for Cas9 binding and cleavage.
Correct answer is: Protospacer adjacent motif (PAM)
Q.28 In a gene therapy clinical trial, the primary endpoint is typically:
The cost of manufacturing
The rate of adverse immune reactions
The improvement in a specific clinical outcome
The number of patients recruited
Explanation - Clinical trials assess whether the therapy yields a measurable therapeutic benefit.
Correct answer is: The improvement in a specific clinical outcome
Q.29 Which of these is an example of an antisense oligonucleotide therapy?
Spinraza (nusinersen)
Onasemnogene abeparvovec (Zolgensma)
Glybera (alipogene tiparvovec)
Adalimumab
Explanation - Spinraza is an ASO that modifies splicing of SMN2 mRNA in spinal muscular atrophy.
Correct answer is: Spinraza (nusinersen)
Q.30 Which of the following is NOT a typical component of a lipid nanoparticle formulation?
Ionizable lipid
Cholesterol
PEGylated lipid
Viral envelope protein
Explanation - LNPs are composed of lipids, not viral proteins.
Correct answer is: Viral envelope protein
Q.31 What is the main reason for using a tissue‑specific promoter in gene therapy?
To reduce manufacturing complexity
To limit therapeutic gene expression to desired tissues
To increase the size of the plasmid
To enhance immune recognition
Explanation - Tissue‑specific promoters restrict gene expression, minimizing off‑target effects.
Correct answer is: To limit therapeutic gene expression to desired tissues
Q.32 Which of the following is a risk associated with integrating viral vectors?
Rapid clearance from blood
Insertional oncogenesis
Short half‑life
Low transduction efficiency
Explanation - Integration into the genome can activate oncogenes or disrupt tumor suppressor genes.
Correct answer is: Insertional oncogenesis
Q.33 The 'codon optimization' step in mRNA design primarily serves to:
Reduce the length of the mRNA
Enhance translation efficiency in target cells
Increase immunogenicity
Add a poly(A) tail
Explanation - Codon optimization uses synonymous codons preferred by the host to boost protein production.
Correct answer is: Enhance translation efficiency in target cells
Q.34 In the context of gene therapy, what does 'ex vivo' refer to?
Delivery of the gene directly to the patient
Modification of cells outside the body before re‑infusion
Administration of the gene via an aerosol
Use of a natural viral vector
Explanation - Ex vivo therapy involves extracting cells, editing them in culture, then returning them to the patient.
Correct answer is: Modification of cells outside the body before re‑infusion
Q.35 Which of the following best describes 'RNA interference' (RNAi)?
Integration of RNA into the DNA genome
A mechanism of gene silencing by small RNA molecules
An antibody‑mediated neutralization of RNA viruses
The process of RNA transcription
Explanation - RNAi uses small RNAs such as siRNA or miRNA to target and degrade complementary mRNAs.
Correct answer is: A mechanism of gene silencing by small RNA molecules
Q.36 Which of these is a major challenge in delivering gene therapy to the central nervous system (CNS)?
The blood‑brain barrier
High immune tolerance
Rapid cellular uptake
Low regulatory scrutiny
Explanation - The BBB limits passage of therapeutic vectors into the brain.
Correct answer is: The blood‑brain barrier
Q.37 Which type of therapeutic nucleic acid is designed to bind directly to mRNA and prevent translation?
siRNA
ASO
mRNA
Plasmid DNA
Explanation - Antisense oligonucleotides pair with mRNA to block ribosome access or trigger degradation.
Correct answer is: ASO
Q.38 The first viral vector used for gene therapy was based on:
Retrovirus
Adenovirus
Adeno‑associated virus (AAV)
Herpes simplex virus
Explanation - Early trials used adenoviruses, though they caused strong immune reactions.
Correct answer is: Adenovirus
Q.39 Why are 'self‑complementary' AAV vectors advantageous?
They have a larger packaging capacity
They lead to faster transgene expression
They are less immunogenic
They integrate into the genome
Explanation - Self‑complementary AAVs form double‑stranded DNA immediately, speeding up gene expression.
Correct answer is: They lead to faster transgene expression
Q.40 Which of the following is a primary mechanism by which viral vectors can cause adverse effects?
Inhibition of host DNA replication
Off‑target RNA degradation
Unwanted immunogenicity
Excessive RNA stability
Explanation - The host immune system may recognize the vector as foreign, leading to inflammation or clearance.
Correct answer is: Unwanted immunogenicity
Q.41 In a gene therapy trial for hemophilia B, the therapeutic gene encodes which protein?
Factor VIII
Factor IX
Factor VII
Factor X
Explanation - Hemophilia B results from deficiency of clotting factor IX; therapy restores its production.
Correct answer is: Factor IX
Q.42 What is the main function of a 5’ cap on mRNA?
To mark the end of the transcript
To enhance translation initiation and protect from degradation
To direct mRNA to the nucleus
To increase the length of the mRNA strand
Explanation - The cap is recognized by the ribosome and protects mRNA from exonucleases.
Correct answer is: To enhance translation initiation and protect from degradation
Q.43 Which of these is a characteristic of adeno‑associated virus (AAV) vectors?
Large genome size (~20 kb)
Strong immunogenicity
Low packaging capacity (~4.7 kb)
Rapid replication in host cells
Explanation - AAV can only carry small genes due to its limited genome size.
Correct answer is: Low packaging capacity (~4.7 kb)
Q.44 What is a primary safety advantage of using non‑integrating vectors?
Permanent gene expression
Reduced risk of insertional mutagenesis
Higher immunogenicity
Unlimited packaging capacity
Explanation - Non‑integrating vectors remain episomal, decreasing the chance of disrupting host genes.
Correct answer is: Reduced risk of insertional mutagenesis
Q.45 Which component of CRISPR-Cas9 is engineered to prevent off‑target activity?
High‑fidelity Cas9 variants
Guide RNA with mismatches
Large PAM sequence
Auxiliary nuclease domain
Explanation - Modified Cas9 enzymes have reduced non‑specific DNA cleavage.
Correct answer is: High‑fidelity Cas9 variants
Q.46 Which of the following best describes the term 'codon usage bias'?
Preference for certain codons in a species to increase translation efficiency
The tendency of codons to be inserted into plasmid vectors
The random distribution of codons in mRNA
A method for sequencing genomes
Explanation - Codon usage bias reflects tRNA abundance, influencing how efficiently proteins are made.
Correct answer is: Preference for certain codons in a species to increase translation efficiency
Q.47 Which of these is a common route of administration for intravenous gene therapy?
Intramuscular injection
Intrathecal injection
Oral ingestion
Topical application
Explanation - Intrathecal delivery allows vectors to reach the CNS via cerebrospinal fluid.
Correct answer is: Intrathecal injection
Q.48 Why is polyethylene glycol (PEG) often conjugated to lipid nanoparticles?
To increase immunogenicity
To stabilize the particles and reduce aggregation
To act as a fluorescent marker
To facilitate endosomal escape
Explanation - PEGylation provides a stealth coating, prolonging circulation time.
Correct answer is: To stabilize the particles and reduce aggregation
Q.49 In the context of gene therapy, what does the term 'phenotypic rescue' mean?
Restoring the normal phenotype of a disease model
Eliminating all phenotypes of a cell
Increasing the number of phenotypes
Replacing the phenotype with a new one
Explanation - Phenotypic rescue indicates that the therapy has corrected the observable traits of the disease.
Correct answer is: Restoring the normal phenotype of a disease model
Q.50 Which of the following is a key consideration when choosing a delivery route for gene therapy?
Patient's dietary habits
Target tissue accessibility
The color of the vector
The brand of the syringe
Explanation - The route must allow the vector to reach the diseased tissue effectively.
Correct answer is: Target tissue accessibility
Q.51 Which of the following is NOT a type of nucleic acid therapy?
siRNA
ASO
Protein‑directed therapy
mRNA vaccine
Explanation - Protein therapy uses proteins directly, not nucleic acids.
Correct answer is: Protein‑directed therapy
Q.52 What is the main role of the 'poly(A) tail' in eukaryotic mRNA?
To encode the protein
To signal for nuclear export and translation
To mark the stop codon
To act as a promoter
Explanation - The poly(A) tail stabilizes mRNA and enhances translation efficiency.
Correct answer is: To signal for nuclear export and translation
Q.53 Which of these is a safety measure for patients receiving gene therapy?
Routine blood pressure checks
Genetic screening for off‑target effects
Avoidance of antibiotics
Exclusion from all other treatments
Explanation - Screening helps detect unintended genomic alterations caused by the therapy.
Correct answer is: Genetic screening for off‑target effects
Q.54 The 'CRISPRa' system is designed to:
Activate gene expression
Deactivate gene expression
Induce DNA repair
Edit the genome via base editing
Explanation - CRISPR activation (CRISPRa) uses a dead Cas9 fused to transcriptional activators.
Correct answer is: Activate gene expression
Q.55 Which of the following is a typical clinical trial phase for evaluating safety of a new gene therapy?
Phase 1
Phase 2
Phase 3
Phase 4
Explanation - Phase 1 trials primarily assess safety and tolerability in a small cohort.
Correct answer is: Phase 1
Q.56 Which of the following best describes 'in vivo gene editing'?
Editing genes outside the body
Editing genes directly inside a living organism
Using viral vectors only
Using chemical mutagens
Explanation - In vivo editing targets cells within the patient without ex vivo manipulation.
Correct answer is: Editing genes directly inside a living organism
Q.57 Why might a gene therapy product be designed to be 'self‑limiting'?
To reduce costs
To prevent uncontrolled gene expression over time
To increase immunogenicity
To allow indefinite replication
Explanation - Self‑limiting designs ensure expression stops after the therapeutic window, reducing side effects.
Correct answer is: To prevent uncontrolled gene expression over time
Q.58 The presence of a 'transgene' refers to:
A host gene that is mutated
An integrated gene delivered by therapy
An immune cell receptor
A viral envelope protein
Explanation - Transgene is the therapeutic gene introduced into the patient’s genome.
Correct answer is: An integrated gene delivered by therapy
Q.59 Which of these is a key factor influencing the stability of mRNA vaccines during storage?
Presence of a poly(A) tail
Temperature and freeze‑thaw cycles
Length of the coding sequence
Type of lipid in the formulation
Explanation - mRNA degrades rapidly at higher temperatures; proper cold‑chain storage is critical.
Correct answer is: Temperature and freeze‑thaw cycles
Q.60 Which of the following is a characteristic of a 'self‑amplifying' RNA vaccine?
It uses viral replication to amplify antigen expression
It integrates into the genome
It requires a viral vector for delivery
It is non‑coding
Explanation - Self‑amplifying RNAs encode an RNA polymerase that replicates the transcript, boosting protein output.
Correct answer is: It uses viral replication to amplify antigen expression
Q.61 Which of the following best describes the 'pseudotyping' of a viral vector?
Changing the genome size
Replacing the viral envelope protein with that from another virus
Adding a fluorescent marker
Removing the viral core
Explanation - Pseudotyping alters tropism by using a different envelope for cell entry.
Correct answer is: Replacing the viral envelope protein with that from another virus
Q.62 The 'clinical benefit' of a gene therapy is primarily measured by:
Reduction in viral load
Improved quality of life and functional outcomes
Number of vector copies delivered
Duration of vector circulation
Explanation - Clinical benefit focuses on patient‑centric outcomes rather than molecular metrics.
Correct answer is: Improved quality of life and functional outcomes
Q.63 Which of these nucleic acid molecules is most commonly used in base‑editing technologies?
DNA
RNA
Adeno‑associated virus
CRISPR guide RNA
Explanation - Guide RNA directs the base‑editor enzyme to specific DNA sites for precise edits.
Correct answer is: CRISPR guide RNA
Q.64 Which of the following is a primary challenge in scaling up production of nucleic acid therapeutics?
Lack of large‑scale synthesis equipment
Unstable storage at low temperatures
Difficulty in purifying small RNAs
All of the above
Explanation - Large‑scale synthesis, storage, and purification all present logistical hurdles.
Correct answer is: All of the above
Q.65 Which of the following is a typical immunogenicity concern for mRNA vaccines?
Induction of anti‑mRNA antibodies
Induction of anti‑lipid nanoparticle antibodies
Integration into host DNA
Inactivation of the host ribosomes
Explanation - Antibodies against LNP components can reduce efficacy or cause adverse reactions.
Correct answer is: Induction of anti‑lipid nanoparticle antibodies
Q.66 The 'Golden Gate' cloning method relies on:
Restriction enzymes that cut at the same site as they ligate
PCR amplification of the insert
Homologous recombination
Use of T7 RNA polymerase
Explanation - Golden Gate uses Type IIs enzymes to create seamless DNA assemblies.
Correct answer is: Restriction enzymes that cut at the same site as they ligate
Q.67 Which of the following best describes a 'dual‑gRNA' system in CRISPR?
Two guide RNAs targeting the same sequence to increase cutting efficiency
A guide RNA and a reverse complement guide
A guide RNA and a spacer DNA
Two guide RNAs targeting two different genes simultaneously
Explanation - Dual‑gRNA systems enhance editing efficiency by providing multiple cuts.
Correct answer is: Two guide RNAs targeting the same sequence to increase cutting efficiency
Q.68 Which of these is a reason to prefer AAV vectors over lentiviruses?
Larger genome capacity
Higher immunogenicity
Safer integration profile
Rapid replication in dividing cells
Explanation - AAVs rarely integrate, lowering oncogenic risk compared to lentiviruses.
Correct answer is: Safer integration profile
Q.69 In the context of nucleic acid therapeutics, what does 'therapeutic window' refer to?
Time period during which the drug remains in the bloodstream
Optimal dosage range where therapeutic effect exceeds toxicity
Period after which the drug is excreted
Time between two consecutive doses
Explanation - The therapeutic window is the dose range providing benefit with acceptable safety.
Correct answer is: Optimal dosage range where therapeutic effect exceeds toxicity
Q.70 Which of the following is a major advantage of using lipid nanoparticles over viral vectors?
They integrate into the genome
They can be engineered to target specific tissues
They are highly immunogenic
They have large packaging capacity
Explanation - LNPs can be surface‑modified to direct delivery to specific cell types.
Correct answer is: They can be engineered to target specific tissues
Q.71 Which of these is a common side effect observed in patients receiving viral vector‑mediated gene therapy?
Hypersensitivity reactions
Diarrhea
Severe hyperglycemia
Hypertension
Explanation - Immune reactions against viral capsids can cause hypersensitivity or inflammation.
Correct answer is: Hypersensitivity reactions
Q.72 Which of the following best describes 'transient expression' in the context of mRNA therapy?
Long‑lasting gene expression
Short‑lived protein production without genome integration
Permanent genomic insertion
Continuous expression from a plasmid
Explanation - mRNA is translated temporarily; it does not persist in the genome.
Correct answer is: Short‑lived protein production without genome integration
Q.73 Which of the following is a primary design consideration for CRISPR guide RNAs?
Minimizing GC content
Avoiding off‑target sequences
Maximizing hairpin formation
Using a 5’ cap
Explanation - Designing guides with unique sequences reduces unintended cuts.
Correct answer is: Avoiding off‑target sequences
Q.74 The 'HIV‑based lentiviral vector' is commonly used for:
Transient expression in dividing cells only
Stable integration into dividing and non‑dividing cells
Delivery of small RNA molecules
Only in plant cells
Explanation - HIV vectors can deliver genes into a wide variety of cell types, integrating into host DNA.
Correct answer is: Stable integration into dividing and non‑dividing cells
Q.75 What is the purpose of the 'spacer' in CRISPR guide RNA?
To anchor the guide to the Cas protein
To provide the sequence that pairs with the target DNA
To terminate transcription
To act as a promoter
Explanation - The spacer is the guide’s target‑complementary sequence.
Correct answer is: To provide the sequence that pairs with the target DNA
Q.76 Which of the following is NOT a typical component of a gene therapy clinical trial protocol?
Inclusion criteria
Dose‑escalation plan
Standard of care comparison
Patient’s favorite color
Explanation - Clinical trial protocols include medical criteria, not personal preferences.
Correct answer is: Patient’s favorite color
Q.77 Which of these is a key advantage of using electroporation for plasmid delivery?
It avoids the need for a promoter
It enhances membrane permeability for DNA uptake
It reduces the risk of insertional mutagenesis
It can only be used in vitro
Explanation - Electric pulses transiently permeabilize cell membranes, allowing plasmid entry.
Correct answer is: It enhances membrane permeability for DNA uptake
Q.78 Which of the following is a potential long‑term risk of integrating viral vectors?
Chronic liver failure
Oncogenesis due to insertional mutagenesis
Acute allergic reaction
Transient fever
Explanation - Integration near oncogenes can trigger cancer development.
Correct answer is: Oncogenesis due to insertional mutagenesis
Q.79 Which of these is a common method to assess the biodistribution of a viral vector?
Serum protein electrophoresis
qPCR for vector genomes in tissues
MRI scanning of the brain
Skin biopsy only
Explanation - qPCR quantifies vector DNA across tissues to determine distribution.
Correct answer is: qPCR for vector genomes in tissues
Q.80 Which of the following is a key feature of 'self‑delivering' RNAi therapeutics?
They require a delivery vehicle
They naturally enter cells via endocytosis
They are packaged in lipid nanoparticles
They need viral vectors for uptake
Explanation - Self‑delivering siRNAs have chemical modifications allowing direct cellular uptake.
Correct answer is: They naturally enter cells via endocytosis
Q.81 Why is a 'serum stability' test important for nucleic acid drugs?
To ensure they are not metabolized by the liver
To confirm they remain intact in the bloodstream until they reach target cells
To measure the drug’s half‑life in the brain
To test for renal clearance
Explanation - Stability in serum predicts how long the therapeutic can circulate before degradation.
Correct answer is: To confirm they remain intact in the bloodstream until they reach target cells
Q.82 Which of these is a hallmark of 'mRNA vaccines' compared to traditional protein subunit vaccines?
They require adjuvants for immunogenicity
They can be produced rapidly in vitro
They integrate into host DNA
They are delivered via live attenuated virus
Explanation - mRNA can be synthesized quickly without needing cell culture or virus passage.
Correct answer is: They can be produced rapidly in vitro
Q.83 Which of the following is a common target for gene editing in treating sickle cell disease?
SMN1 gene
β‑globin gene (HBB)
Factor IX gene
CFTR gene
Explanation - Editing HBB can correct the mutation that causes sickle cell disease.
Correct answer is: β‑globin gene (HBB)
Q.84 What is a main advantage of using a 'self‑amplifying RNA' platform for vaccine development?
It reduces the required antigen dose
It integrates into the host genome
It increases the half‑life of the mRNA
It eliminates the need for lipid nanoparticles
Explanation - Amplification leads to higher protein expression from lower amounts of RNA.
Correct answer is: It reduces the required antigen dose
Q.85 In gene therapy, 'CRISPR base editing' achieves:
Double‑stranded breaks and non‑homologous end joining
Direct conversion of one DNA base to another without cuts
Insertion of large DNA fragments
Random mutagenesis
Explanation - Base editors convert a single base pair, minimizing DNA damage.
Correct answer is: Direct conversion of one DNA base to another without cuts
Q.86 The 'GFP reporter system' is used to:
Measure cell division rates
Visualize transgene expression in live cells
Quantify protein degradation
Track immune cell migration
Explanation - Green fluorescent protein indicates successful gene delivery and expression.
Correct answer is: Visualize transgene expression in live cells
Q.87 Which of the following is a key factor for successful gene delivery across the blood‑brain barrier?
Small vector size
High immunogenicity
Large viral envelope
No targeting ligand
Explanation - Smaller particles or vectors are more likely to cross the BBB.
Correct answer is: Small vector size
Q.88 Why is 'mRNA codon optimization' performed before manufacturing?
To increase the number of stop codons
To reduce the length of the mRNA strand
To improve translation efficiency in the host organism
To ensure the mRNA integrates into the genome
Explanation - Optimized codons match host tRNA abundance, enhancing protein production.
Correct answer is: To improve translation efficiency in the host organism
Q.89 In nucleic acid therapeutics, what is the purpose of a '3’ poly(A) tail'?
To promote mRNA degradation
To serve as a start codon
To improve mRNA stability and translation
To inhibit ribosomal binding
Explanation - The poly(A) tail protects mRNA from exonucleases and enhances translation efficiency.
Correct answer is: To improve mRNA stability and translation
Q.90 Which of the following is a potential benefit of using 'synthetic biology' in gene therapy?
Increased unpredictability of vector behavior
Precise control over gene expression timing
Higher viral immunogenicity
Lower manufacturing yield
Explanation - Synthetic biology enables the design of circuits that respond to specific cues.
Correct answer is: Precise control over gene expression timing
Q.91 The 'Bla-3' system in CRISPR screening is used for:
Selection of antibiotic‑resistant clones
Fluorescent sorting of cells
Enrichment of cells with a specific phenotype
Measuring viral load
Explanation - Bla-3 (beta-lactamase) allows selection of cells that survive antibiotic treatment.
Correct answer is: Enrichment of cells with a specific phenotype
Q.92 What is a key feature of 'non‑viral electroporation' for gene delivery?
Requires viral capsids
Does not need a promoter
Can be used for large DNA fragments
Is only suitable for ex vivo use
Explanation - Electroporation can deliver plasmids of several kilobases, including large therapeutic genes.
Correct answer is: Can be used for large DNA fragments
Q.93 Which of the following is a major advantage of using 'AAV9' vectors?
High packaging capacity (~20 kb)
Strong tropism for the heart and CNS
Rapid clearance from the bloodstream
High integration frequency
Explanation - AAV9 efficiently transduces cardiac and neural tissues, useful for related diseases.
Correct answer is: Strong tropism for the heart and CNS
Q.94 Which of these is NOT a common adverse event reported for CRISPR‑based therapies?
Inflammation
Genomic instability
Allergic reactions
Infection by the editing enzyme
Explanation - CRISPR enzymes are not pathogens and cannot cause infections.
Correct answer is: Infection by the editing enzyme
Q.95 Why is a 'promoter strength' important in plasmid design?
It determines plasmid replication rate
It controls the level of transgene expression
It influences plasmid stability in the host
It affects the plasmid size
Explanation - Strong promoters drive high-level gene expression, while weak promoters yield low expression.
Correct answer is: It controls the level of transgene expression
Q.96 Which of the following best defines 'immune tolerance' in the context of gene therapy?
The immune system attacks the vector
The immune system fails to recognize the vector or therapeutic protein
The immune system over‑reacts to the vector
The immune system becomes hyperactive
Explanation - Immune tolerance allows the therapy to persist without provoking an immune attack.
Correct answer is: The immune system fails to recognize the vector or therapeutic protein
Q.97 Which of the following is a typical method used to measure the activity of a delivered gene in a clinical trial?
Serum glucose levels
Enzyme activity assays in blood samples
Skin temperature
Blood pressure monitoring
Explanation - Measuring the enzyme or protein produced by the transgene confirms therapeutic activity.
Correct answer is: Enzyme activity assays in blood samples
Q.98 What is the purpose of an 'antimicrobial resistance marker' in plasmid vectors?
To provide the therapeutic protein
To allow selection of bacteria carrying the plasmid
To increase plasmid copy number
To facilitate vector integration
Explanation - Resistance markers enable the growth of only bacteria that contain the plasmid.
Correct answer is: To allow selection of bacteria carrying the plasmid
Q.99 Which of the following is a characteristic of 'RNA‑based vaccines' in terms of immune response?
They cause persistent infection
They primarily trigger B‑cell responses only
They induce both humoral and cellular immunity
They integrate into host DNA
Explanation - mRNA vaccines generate antigen production that stimulates antibody and T‑cell responses.
Correct answer is: They induce both humoral and cellular immunity
Q.100 Which of the following best describes the 'insertional mutagenesis' risk associated with viral vectors?
The vector integrates into a random site, possibly disrupting genes
The vector is unable to integrate into the host genome
The vector degrades host DNA
The vector only targets non‑coding regions
Explanation - Random insertion can activate oncogenes or inactivate tumor suppressors.
Correct answer is: The vector integrates into a random site, possibly disrupting genes
Q.101 Which of the following is a main reason for using 'self‑delivering siRNA' rather than lipid nanoparticles?
Lower cost of manufacturing
Higher immunogenicity
Requirement for viral vectors
Need for higher dose
Explanation - Self‑delivering siRNAs have chemical modifications that allow cellular uptake without complex delivery vehicles.
Correct answer is: Lower cost of manufacturing
Q.102 In the context of gene therapy, what does 'transgene silencing' refer to?
The loss of the therapeutic gene from the genome
The reduction of transgene expression due to epigenetic changes
The activation of the transgene at high levels
The integration of the transgene into the mitochondrial genome
Explanation - Silencing occurs when DNA methylation or histone modifications reduce transcription of the delivered gene.
Correct answer is: The reduction of transgene expression due to epigenetic changes
Q.103 Which of the following is a primary benefit of using 'AAV' vectors for ocular gene therapy?
They integrate into the host genome
They have a low immunogenicity profile in the eye
They are the largest viral vectors available
They can replicate autonomously in ocular tissues
Explanation - The eye’s immune privilege and AAV’s low immunogenicity make it suitable for ocular delivery.
Correct answer is: They have a low immunogenicity profile in the eye
Q.104 Which of the following statements about CRISPR-Cas9 is FALSE?
It requires a PAM sequence near the target site
It can cause double‑strand breaks in DNA
It can be used for base editing without cutting the DNA
It is derived from a bacterial immune system
Explanation - Standard CRISPR‑Cas9 creates double‑strand breaks; base editing uses engineered variants.
Correct answer is: It can be used for base editing without cutting the DNA
Q.105 Which of the following is an advantage of 'mRNA vaccines' over live‑attenuated vaccines?
They can cause long‑term immunity without boosters
They are less likely to integrate into the host genome
They are more immunogenic without adjuvants
They do not require cold‑chain storage
Explanation - mRNA remains in the cytoplasm and does not integrate, reducing oncogenic risk.
Correct answer is: They are less likely to integrate into the host genome
Q.106 Which of the following is a critical consideration when selecting a promoter for a tissue‑specific gene therapy?
Promoter must be the same in all tissues
Promoter should be constitutive in all cell types
Promoter should be highly active only in target tissue
Promoter should be derived from a virus
Explanation - Tissue‑specific promoters restrict transgene expression to the desired site.
Correct answer is: Promoter should be highly active only in target tissue
Q.107 Which of the following is an example of a therapeutic nucleic acid designed to modify RNA splicing?
Antisense oligonucleotide
siRNA
mRNA vaccine
DNA plasmid
Explanation - ASOs can bind splice sites and alter splicing patterns to produce a functional protein.
Correct answer is: Antisense oligonucleotide
Q.108 Which of the following is a characteristic of the 'Adeno‑associated virus (AAV) vector' regarding genome integration?
High integration rate
No integration, episomal persistence
Integration only in dividing cells
Integration exclusively in mitochondrial DNA
Explanation - AAV generally remains episomal, which reduces insertional mutagenesis risk.
Correct answer is: No integration, episomal persistence
Q.109 What is the role of a 'polyadenylation signal' in mRNA constructs?
To start transcription
To signal RNA polymerase termination
To direct the RNA to the ribosome
To stabilize the mRNA and aid export
Explanation - The polyadenylation signal leads to cleavage and addition of the poly(A) tail.
Correct answer is: To stabilize the mRNA and aid export
Q.110 Which of the following is a potential advantage of using 'CRISPR-Cas13' over Cas9?
It targets DNA sequences
It causes double‑strand breaks
It targets RNA rather than DNA
It is a viral vector
Explanation - Cas13 cleaves RNA, allowing post‑transcriptional regulation or antiviral activity.
Correct answer is: It targets RNA rather than DNA
Q.111 Which of these best describes the 'clinical benefit' metric used for evaluating gene therapy?
The number of viral particles administered
The level of expression of the transgene in the target tissue
The reduction in disease symptoms or progression
The amount of vector DNA in the blood
Explanation - Clinical benefit focuses on tangible health improvements for patients.
Correct answer is: The reduction in disease symptoms or progression
Q.112 Which of the following is a major hurdle in delivering gene therapy to the lungs?
Large size of viral vectors
High immune clearance by alveolar macrophages
Difficulty in nebulization
All of the above
Explanation - Lung delivery faces multiple challenges including vector size, immune cells, and formulation.
Correct answer is: All of the above
Q.113 In an siRNA therapeutic, what is the significance of the 5’ overhang?
It helps the siRNA to be degraded more quickly
It directs the siRNA to the nucleus
It facilitates incorporation into the RISC complex
It blocks RNA binding
Explanation - The 5’ overhang is recognized by Argonaute proteins, enabling effective RNAi.
Correct answer is: It facilitates incorporation into the RISC complex
Q.114 Which of the following is a typical use for a 'cell‑penetrating peptide' in nucleic acid therapeutics?
To act as a promoter
To enhance cellular uptake of nucleic acids
To serve as a therapeutic gene
To integrate into the genome
Explanation - CPPs facilitate crossing the cell membrane, improving delivery of DNA or RNA.
Correct answer is: To enhance cellular uptake of nucleic acids
Q.115 Which of the following best explains why mRNA vaccines do not require a promoter in the plasmid construct?
mRNA is produced directly by T7 RNA polymerase
Promoters are not needed for RNA synthesis
The mRNA sequence contains its own promoter
mRNA is not transcribed from DNA
Explanation - In vitro transcription using T7 polymerase generates mRNA independent of eukaryotic promoters.
Correct answer is: mRNA is produced directly by T7 RNA polymerase
Q.116 What does the 'pseudotyping' of lentiviral vectors accomplish?
Allows them to replicate in host cells
Modifies their envelope to change cell tropism
Increases the size of the vector genome
Reduces the need for a promoter
Explanation - Pseudotyping swaps the viral envelope to target different cell types.
Correct answer is: Modifies their envelope to change cell tropism
Q.117 Which of the following is a common safety assessment in gene therapy clinical trials?
Serum cytokine levels
Blood glucose monitoring
Body temperature recording
Eye color changes
Explanation - Cytokine profiling helps detect inflammatory responses to the therapy.
Correct answer is: Serum cytokine levels
Q.118 Which of the following is a primary benefit of using 'self‑amplifying mRNA' for vaccine development?
Requires higher antigen doses
Reduces antigen expression
Enables lower antigen doses due to in‑cell amplification
Requires viral vectors
Explanation - Self‑amplifying mRNA replicates inside cells, generating more antigen from less material.
Correct answer is: Enables lower antigen doses due to in‑cell amplification
Q.119 Which of the following is a key component of a CRISPR-Cas9 plasmid used for gene editing?
Guide RNA (gRNA)
Promoter for Cas9
Selection marker
All of the above
Explanation - A functional plasmid contains gRNA, Cas9 promoter, and a selection marker.
Correct answer is: All of the above
Q.120 What is a major advantage of using 'DNA plasmid' vectors for in vitro experiments?
They integrate into the host genome automatically
They can carry large DNA fragments
They are immune‑privileged
They do not need a promoter
Explanation - Plasmids can accommodate large inserts, useful for expressing complex proteins.
Correct answer is: They can carry large DNA fragments
Q.121 Which of these is a potential risk when using a 'self‑delivering siRNA' that lacks a delivery vehicle?
Lower cellular uptake
Increased immunogenicity
Higher manufacturing cost
Integration into the genome
Explanation - Without carriers, siRNA may be taken up less efficiently and cleared quickly.
Correct answer is: Lower cellular uptake
Q.122 Why is 'codon optimization' important when designing mRNA vaccines?
It increases the number of stop codons
It reduces the mRNA size
It enhances translation efficiency in the host cells
It prevents integration into host DNA
Explanation - Optimized codons match abundant tRNAs, improving protein yield.
Correct answer is: It enhances translation efficiency in the host cells
Q.123 Which of the following is NOT a typical characteristic of a 'clinical trial' for a gene therapy product?
Phase designation (1, 2, 3, 4)
Randomized patient allocation
Placebo control group
No inclusion or exclusion criteria
Explanation - Clinical trials always define inclusion and exclusion criteria to select participants.
Correct answer is: No inclusion or exclusion criteria
Q.124 Which of these is an advantage of 'ex vivo' gene therapy approaches?
Direct delivery to the bloodstream
Ability to screen and expand modified cells before re‑infusion
Higher risk of insertional mutagenesis
No need for ex vivo manipulation
Explanation - Ex vivo methods allow thorough testing of edited cells before they enter the patient.
Correct answer is: Ability to screen and expand modified cells before re‑infusion
Q.125 What is the main role of the 'poly(A) tail' in eukaryotic mRNA?
To encode the protein
To signal for nuclear export and enhance stability
To serve as a start codon
To inhibit ribosome binding
Explanation - The poly(A) tail protects the mRNA and aids its export to the cytoplasm.
Correct answer is: To signal for nuclear export and enhance stability
Q.126 Which of the following is a typical method to evaluate the immunogenicity of an AAV vector?
ELISA for anti‑AAV antibodies
PCR for vector genome copies
Serum albumin measurement
Blood pressure monitoring
Explanation - ELISA detects antibodies that neutralize the vector or cause adverse reactions.
Correct answer is: ELISA for anti‑AAV antibodies
Q.127 What is a potential advantage of using a 'dual‑gRNA' strategy in CRISPR editing?
Increases cutting specificity
Reduces editing efficiency
Increases off‑target effects
Requires two separate viral vectors
Explanation - Two guides can cut flanking sites, ensuring precise deletion with lower off‑target risk.
Correct answer is: Increases cutting specificity
Q.128 Which of these is a major challenge for delivering nucleic acid drugs to the brain?
Large vector size
Blood‑brain barrier permeability
High immunogenicity of mRNA
All of the above
Explanation - The BBB limits passage of many therapeutic molecules, including nucleic acids.
Correct answer is: Blood‑brain barrier permeability
Q.129 In the context of gene therapy, what is a 'transient' versus a 'stable' transgene expression?
Transient: permanent; stable: temporary
Transient: short‑lived; stable: long‑lasting
Transient: integrates; stable: does not integrate
Transient: in the nucleus; stable: in the cytoplasm
Explanation - Transient expression occurs with non‑integrating vectors; stable requires integration or episomal persistence.
Correct answer is: Transient: short‑lived; stable: long‑lasting
Q.130 Which of the following best describes an 'antigen‑presenting cell' in the context of mRNA vaccine action?
A cell that produces antibodies
A cell that displays antigens on its surface to T cells
A cell that secretes mRNA
A cell that integrates the mRNA into its DNA
Explanation - APCs present vaccine‑encoded antigens via MHC molecules, activating T cells.
Correct answer is: A cell that displays antigens on its surface to T cells
Q.131 Which of these is an advantage of using 'non‑viral synthetic polymers' for nucleic acid delivery?
They integrate into the host genome
They have high immunogenicity
They are versatile and can be engineered for specific cell types
They require viral capsids
Explanation - Synthetic polymers can be functionalized for targeted delivery without viruses.
Correct answer is: They are versatile and can be engineered for specific cell types
Q.132 Which of the following is a common feature of 'self‑amplifying RNA' vaccines?
They encode an RNA-dependent RNA polymerase
They are delivered using viral vectors
They do not require a 5’ cap
They integrate into the host genome
Explanation - Self‑amplifying RNA contains sequences for replication, boosting antigen expression.
Correct answer is: They encode an RNA-dependent RNA polymerase
Q.133 What is the purpose of an 'antidote oligonucleotide' in antisense therapy?
To enhance gene silencing
To neutralize toxic byproducts of antisense binding
To reverse or reduce off‑target effects of the ASO
To serve as a promoter
Explanation - Antidotes can bind and sequester antisense oligonucleotides, mitigating adverse effects.
Correct answer is: To reverse or reduce off‑target effects of the ASO
Q.134 Which of the following is NOT typically included in a gene therapy manufacturing process?
Cell culture scale‑up
Purification of the viral vector
Quality control assays
DNA sequencing of the patient
Explanation - Manufacturing focuses on vector production; patient sequencing is clinical, not production.
Correct answer is: DNA sequencing of the patient
Q.135 Which of these is a common method for evaluating the efficacy of a gene therapy in a preclinical animal model?
Behavioral assays in mice
Serum glucose measurement
Skin temperature monitoring
Blood pressure measurement
Explanation - Functional assays demonstrate therapeutic impact in disease‑specific animal models.
Correct answer is: Behavioral assays in mice
Q.136 Which of the following statements about 'CRISPR base editing' is true?
It induces double‑strand breaks
It requires donor DNA templates
It converts a single base without cutting DNA
It is only applicable to bacterial genomes
Explanation - Base editors chemically alter a base pair in situ, avoiding DNA breaks.
Correct answer is: It converts a single base without cutting DNA
Q.137 Which of these is an example of a 'cell‑penetrating peptide' used in nucleic acid delivery?
TAT peptide
GFP protein
mRNA cap
LNP core
Explanation - TAT is derived from HIV and facilitates translocation across cell membranes.
Correct answer is: TAT peptide
Q.138 Which of the following is a primary goal when designing an 'in vitro transcription template' for mRNA vaccine production?
To include a viral promoter
To minimize CpG motifs that stimulate innate immunity
To maximize the length of the template
To integrate the sequence into the genome
Explanation - CpG motifs can trigger immune sensors; their reduction improves mRNA tolerability.
Correct answer is: To minimize CpG motifs that stimulate innate immunity
Q.139 Which of these is a typical component of the 'RISC' complex used in siRNA function?
Argonaute protein
DNA polymerase
Reverse transcriptase
Capsid protein
Explanation - Argonaute is the core protein that binds siRNA and mediates target cleavage.
Correct answer is: Argonaute protein
Q.140 What is the purpose of a 'selection marker' in plasmid construction?
To help the plasmid integrate into the genome
To allow antibiotic selection of transformed cells
To promote plasmid replication
To encode the therapeutic protein
Explanation - The marker (e.g., kanamycin resistance) ensures only cells with the plasmid survive.
Correct answer is: To allow antibiotic selection of transformed cells
Q.141 Which of the following is a reason for using 'AAV' vectors in ocular gene therapy?
They are immunogenic in the eye
They can efficiently transduce retinal cells with low immunogenicity
They integrate into the host genome
They require a large payload
Explanation - AAV’s low immunogenicity and tropism make it suitable for the eye.
Correct answer is: They can efficiently transduce retinal cells with low immunogenicity