Scope and limitations of bioassays MCQs With Answer

Introduction

Scope and limitations of bioassays MCQs With Answer is designed for M.Pharm students to deepen understanding of how biological assays evaluate drug potency, efficacy and safety. This set focuses on principles, statistical approaches, assay types (in vivo, in vitro), standardization issues, and practical constraints such as biological variability, reproducibility, ethical concerns, and regulatory expectations. Each question targets critical thinking about assay selection, interpretation of dose–response relationships, choice of reference standards, and methods to reduce bias and improve accuracy. These MCQs will help students prepare for exams and practical situations by highlighting both the power and the boundaries of bioassays in drug evaluation.

Q1. What primary purpose do bioassays serve in pharmaceutical evaluation?

• To identify the chemical structure of an unknown compound
• To determine the biological potency and activity of a substance
• To measure the physical properties like melting point
• To produce large-scale quantities of a drug

Correct Answer: To determine the biological potency and activity of a substance

Q2. Which of the following best distinguishes bioassays from chemical assays?

• Chemical assays measure biological response, bioassays measure concentration
• Bioassays assess functional biological effect, chemical assays quantify chemical amount
• Bioassays are always faster than chemical assays
• Chemical assays do not require standards

Correct Answer: Bioassays assess functional biological effect, chemical assays quantify chemical amount

Q3. Which type of bioassay is most appropriate for detecting intrinsic biological activity mediated by receptors?

• Chromatographic assay
• Receptor binding assay or functional cell-based assay
• Gravimetric assay
• Thermal stability assay

Correct Answer: Receptor binding assay or functional cell-based assay

Q4. In bioassay terminology, ED50 refers to which parameter?

• The dose producing a toxic effect in 50% of animals
• The dose required to kill 50% of cells in culture
• The effective dose producing 50% of the maximal response
• The enzyme dissociation constant at 50% activity

Correct Answer: The effective dose producing 50% of the maximal response

Q5. Which statistical approach is commonly used to compare potencies in parallel-line bioassays?

• Kaplan-Meier survival analysis
• Parallel-line linear regression and relative potency estimation
• Chi-square test for independence
• Principal component analysis

Correct Answer: Parallel-line linear regression and relative potency estimation

Q6. A major limitation of in vivo bioassays compared with in vitro assays is:

• They cannot measure systemic responses
• Higher biological variability and ethical concerns with animal use
• Lower scientific relevance to whole-organism effects
• They are always less sensitive than in vitro assays

Correct Answer: Higher biological variability and ethical concerns with animal use

Q7. Why is the choice of an appropriate reference standard critical in bioassays?

• Standards are only needed for chromatographic assays
• Reference standards allow meaningful potency comparisons and assay validity
• Standards reduce the assay time by half
• Choice of standard does not affect statistical analysis

Correct Answer: Reference standards allow meaningful potency comparisons and assay validity

Q8. Which factor most compromises the reproducibility of biological assays?

• Using the same certified reference standard
• High inter- and intra-animal or cell-line biological variability
• Strictly following a validated SOP
• Performing technical replicates

Correct Answer: High inter- and intra-animal or cell-line biological variability

Q9. Sensitivity in a bioassay refers to:

• The ability to distinguish between two different chemical structures
• The lowest concentration or dose that produces a measurable biological response
• The rate at which the assay can be completed
• The assay’s resistance to interference from solvents

Correct Answer: The lowest concentration or dose that produces a measurable biological response

Q10. Which limitation is particularly important when interpreting bioassay potency for biologics (e.g., monoclonal antibodies)?

• Biologics do not require reference standards
• Post-translational modifications and conformational heterogeneity can change activity
• Biologics always show zero variability in assays
• Small molecule assay approaches apply without modification

Correct Answer: Post-translational modifications and conformational heterogeneity can change activity

Q11. Which assay design element helps control for time-dependent drift in biological response?

• Run all test samples before running any standards
• Randomization and interspersing standards and controls throughout the run
• Using a single replicate of each sample
• Avoiding the inclusion of negative controls

Correct Answer: Randomization and interspersing standards and controls throughout the run

Q12. Quantal bioassays differ from quantal (this should read: quantitative) assays mainly because quantal assays measure:

• Continuous graded responses such as enzyme activity
• Binary outcomes (e.g., alive/dead) producing dose–response proportions
• Only chemical concentration values
• Physical properties like viscosity

Correct Answer: Binary outcomes (e.g., alive/dead) producing dose–response proportions

Q13. Which regulatory consideration limits the routine use of certain in vivo bioassays?

• Requirement for subjective reporting
• Animal welfare regulations and the 3Rs (replacement, reduction, refinement)
• Inability to generate potency estimates
• Excessive analytical sensitivity

Correct Answer: Animal welfare regulations and the 3Rs (replacement, reduction, refinement)

Q14. A potency estimate expressed as “relative potency” typically requires:

• No reference material and no dose–response data
• A parallel dose–response relationship between test and reference preparations
• Only a single concentration of the test sample
• Qualitative assessment by experts

Correct Answer: A parallel dose–response relationship between test and reference preparations

Q15. Which limitation is common to both in vitro and in vivo bioassays when assessing drug safety?

• Complete prediction of human clinical toxicity is not always possible due to model limitations
• Both always require human volunteers
• Neither can be validated statistically
• They provide exact clinical dosing information without clinical trials

Correct Answer: Complete prediction of human clinical toxicity is not always possible due to model limitations

Q16. The term ‘specificity’ in the context of a bioassay indicates:

• Assay’s ability to detect only the analyte of interest without cross-reactivity
• The time it takes to perform the assay
• How many replicates are needed
• The cost per assay run

Correct Answer: Assay’s ability to detect only the analyte of interest without cross-reactivity

Q17. Why are validation parameters such as linearity and precision important in bioassays?

• They ensure the assay is fashionable
• They demonstrate the assay provides reliable, reproducible and interpretable potency estimates
• They eliminate the need for statistical analysis
• They reduce biological variability to zero

Correct Answer: They demonstrate the assay provides reliable, reproducible and interpretable potency estimates

Q18. Which factor most directly affects the accuracy (trueness) of a bioassay result?

• Random pipetting error only
• Systematic bias such as an incorrect standard concentration or calibration error
• Number of colors used in graphical presentation
• Whether the lab uses glass or plasticware exclusively

Correct Answer: Systematic bias such as an incorrect standard concentration or calibration error

Q19. In the context of bioassays for biosimilars, a key limitation is:

• Biosimilars do not require any bioassay comparison
• Subtle differences in post-translational modifications can alter biological activity despite similar primary sequences
• Biosimilars always have identical immunogenicity profiles
• Bioassays can replace all clinical comparability studies

Correct Answer: Subtle differences in post-translational modifications can alter biological activity despite similar primary sequences

Q20. Which approach can most effectively reduce variability introduced by biological assay systems?

• Using fewer replicates to minimize data spread
• Standardizing cell lines/animal strains, rigorous SOPs, appropriate controls and statistical design
• Avoiding use of reference standards to simplify workflow
• Performing all assays at different uncontrolled environmental conditions

Correct Answer: Standardizing cell lines/animal strains, rigorous SOPs, appropriate controls and statistical design

Download