Biosensor definition and characteristics MCQs With Answer

Biosensor definition and characteristics MCQs With Answer

by

Biosensor definition and characteristics MCQs With Answer

This set of MCQs is designed for M.Pharm students studying Advanced Pharmaceutical Biotechnology. It focuses on precise definitions, core components, and critical performance characteristics of biosensors used in pharmaceutical analysis and drug development. Questions probe depth beyond basic concepts — addressing transducer types, biorecognition elements, analytical figures of merit (sensitivity, limit of detection, linear range), immobilization strategies, stability and reproducibility issues, and integration into point-of-care and microfluidic systems. Use these questions to test conceptual understanding, prepare for viva voce and university examinations, and reinforce the ability to evaluate biosensor suitability for specific pharmaceutical applications.

Q1. What is the most accurate concise definition of a biosensor?

  • An analytical device that uses a biological recognition element closely coupled to a physical transducer to produce a measurable signal proportional to analyte concentration
  • A device that amplifies chemical reactions for chromatographic separation
  • A reagent-based strip test that gives qualitative color change only
  • An instrument that measures only the mass of biomolecules without recognition elements

Correct Answer: An analytical device that uses a biological recognition element closely coupled to a physical transducer to produce a measurable signal proportional to analyte concentration

Q2. Which component of a biosensor is primarily responsible for converting the biochemical interaction into a measurable electrical, optical or other physical signal?

  • The biorecognition element (e.g., enzyme, antibody)
  • The transducer
  • The reference electrode
  • The sample delivery membrane

Correct Answer: The transducer

Q3. Which characteristic best describes “selectivity” in the context of biosensors?

  • The ability to produce a large output signal for a given analyte concentration
  • The ability to distinguish the target analyte from structurally or chemically similar interferents
  • The time required to reach 90% of the steady-state response
  • The device’s long-term storage life at room temperature

Correct Answer: The ability to distinguish the target analyte from structurally or chemically similar interferents

Q4. Sensitivity of a biosensor is best defined as which of the following?

  • The lowest concentration that can be reliably quantified
  • The slope of the calibration curve relating signal change to analyte concentration
  • The maximum concentration that produces a linear response
  • The percentage recovery in spiked samples

Correct Answer: The slope of the calibration curve relating signal change to analyte concentration

Q5. Which of the following transducer types is most commonly used in glucose point-of-care biosensors due to direct enzymatic electron transfer or mediator systems?

  • Optical (absorbance/fluorescence)
  • Piezoresistive
  • Electrochemical (amperometric/potentiometric)
  • Thermal (microcalorimetric)

Correct Answer: Electrochemical (amperometric/potentiometric)

Q6. An affinity biosensor distinguishes itself from a catalytic biosensor by which primary mechanism?

  • Using an enzyme to convert substrate into products that generate signal
  • Relying on reversible binding interactions (e.g., antibody–antigen, aptamer–target) without chemical turnover
  • Measuring heat released during enzymatic reactions
  • Detecting mass changes using piezoelectric crystals only when substrates are hydrolysed

Correct Answer: Relying on reversible binding interactions (e.g., antibody–antigen, aptamer–target) without chemical turnover

Q7. Which immobilization technique is generally preferred when preserving enzyme active site accessibility and orientation for biosensor construction?

  • Random physical adsorption on hydrophobic surfaces
  • Cross-linking with glutaraldehyde without spacer molecules
  • Covalent attachment through oriented linkers (e.g., affinity tags or thiol–gold chemistry)
  • Entrapment in thick non-porous polymer films that block diffusion

Correct Answer: Covalent attachment through oriented linkers (e.g., affinity tags or thiol–gold chemistry)

Q8. Which parameter most directly determines the smallest concentration of analyte that can be confidently detected above baseline noise?

  • Linear dynamic range
  • Limit of detection (LOD)
  • Response time
  • Regeneration capability

Correct Answer: Limit of detection (LOD)

Q9. In biosensor performance assessment, what does “response time” or t90 typically indicate?

  • The time to recover baseline after sensor regeneration
  • The time to reach 90% of the steady-state signal after sample introduction
  • The total operational lifetime before replacement
  • The interval between calibrations required for linearity

Correct Answer: The time to reach 90% of the steady-state signal after sample introduction

Q10. Which factor is the major cause of sensor signal drift over extended continuous use?

  • Electronic noise from the measurement instrument only
  • Loss of bioactivity or leaching/denaturation of the recognition element and fouling of the transducer surface
  • Instantaneous changes in ambient temperature with no cumulative effects
  • Presence of ideal buffer conditions that stabilize the bioreceptor indefinitely

Correct Answer: Loss of bioactivity or leaching/denaturation of the recognition element and fouling of the transducer surface

Q11. For a biosensor intended for therapeutic drug monitoring in plasma, which characteristic is most critical?

  • Ultra-fast response time regardless of accuracy
  • High selectivity in complex biological matrices and low matrix effects
  • Operation only at extreme pH ranges
  • Dependence on large sample volumes (>10 mL)

Correct Answer: High selectivity in complex biological matrices and low matrix effects

Q12. Which statement best describes the linear dynamic range of a biosensor?

  • The concentration interval over which sensor response is directly proportional to analyte concentration within acceptable error limits
  • The minimum concentration detectable above zero noise
  • The ratio of signal to background at a single concentration
  • The maximum number of regeneration cycles supported

Correct Answer: The concentration interval over which sensor response is directly proportional to analyte concentration within acceptable error limits

Q13. Which biorecognition element provides the greatest potential for synthetic reproducibility, stability, and regeneration in affinity biosensors?

  • Polyclonal antibodies raised in animals
  • Aptamers (nucleic acid-based ligands)
  • Whole live cells with metabolic activity
  • Crude tissue extracts containing multiple proteins

Correct Answer: Aptamers (nucleic acid-based ligands)

Q14. What is the primary advantage of optical label-free techniques (e.g., SPR) in biosensor assays for pharmaceutical research?

  • Able to measure mass changes without providing kinetic binding data
  • Direct real-time monitoring of binding kinetics and affinity without labels
  • Requires bulky labels that increase sensitivity dramatically
  • Only suitable for small molecules and not for macromolecules

Correct Answer: Direct real-time monitoring of binding kinetics and affinity without labels

Q15. Which metric indicates reproducibility between repeated measurements under unchanged conditions on a biosensor?

  • Limit of detection (LOD)
  • Coefficient of variation (CV) or relative standard deviation (RSD)
  • Signal drift over several days
  • Time to first calibration

Correct Answer: Coefficient of variation (CV) or relative standard deviation (RSD)

Q16. Which immobilization approach is most likely to permit easy sensor surface regeneration for multiple assay cycles?

  • Permanent covalent attachment of antibodies without cleavable linkers
  • Reversible affinity-based capture (e.g., biotin–streptavidin with competitive elution or his-tag/Ni-NTA reversible binding)
  • Entrapment in irreversible cross-linked polymers
  • Random adsorption with strong hydrophobic interactions

Correct Answer: Reversible affinity-based capture (e.g., biotin–streptavidin with competitive elution or his-tag/Ni-NTA reversible binding)

Q17. In electrochemical biosensors, which source of noise often limits low concentration measurements and must be minimized?

  • Photon shot noise
  • Thermal (Johnson) noise and electrode surface flicker (1/f) noise
  • Acoustic vibrations only
  • Magnetic interference that is independent of electrode design

Correct Answer: Thermal (Johnson) noise and electrode surface flicker (1/f) noise

Q18. Which description best fits a “point-of-care” biosensor requirement in pharmaceutical applications?

  • Large laboratory analyzer with high throughput suitable only for centralized labs
  • Portable, user-friendly device with rapid results, minimal sample prep, and clinical-grade accuracy for near-patient testing
  • Device that requires trained molecular biologists and long incubation times
  • Sensor that must be recalibrated hourly and consumes large reagent volumes

Correct Answer: Portable, user-friendly device with rapid results, minimal sample prep, and clinical-grade accuracy for near-patient testing

Q19. What is the principal reason to integrate microfluidics with biosensor platforms in pharmaceutical assays?

  • To increase required sample volumes and sample handling complexity
  • To enable precise fluid handling, reduce sample/reagent consumption, and improve mass transport to biorecognition sites for faster, more sensitive assays
  • To prevent automation and force manual pipetting for accuracy
  • To eliminate the need for any signal transduction element

Correct Answer: To enable precise fluid handling, reduce sample/reagent consumption, and improve mass transport to biorecognition sites for faster, more sensitive assays

Q20. When validating a biosensor for quantitative pharmaceutical analysis, which combination of performance characteristics must be reported according to good analytical practice?

  • Only the response time and device color
  • LOD, LOQ, linearity, precision (intra- and inter-assay), accuracy (recovery), specificity/selectivity, and stability
  • Only the longest storage life claim
  • Just the manufacturer’s brand and price

Correct Answer: LOD, LOQ, linearity, precision (intra- and inter-assay), accuracy (recovery), specificity/selectivity, and stability

Leave a Comment