Introduction: Biosensors integrate a biological recognition element with a physical transducer to convert biochemical interactions into measurable signals. B. Pharm students must understand working principles — including enzymatic, immunosensor, and nucleic-acid recognition — and common transduction modes such as electrochemical, optical, piezoelectric, and thermal detection. Key topics include bioreceptor immobilization, sensitivity, selectivity, limit of detection, response time, and stability. Industrial applications span pharmaceutical quality control, process monitoring, drug discovery, point-of-care diagnostics, and environmental surveillance. Emerging trends involve nanomaterials, microfluidics, and wearable biosensors. This focused overview will prepare you for application-based questions and practical decision-making. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which component of a biosensor is responsible for specific recognition of the analyte?
- Transducer
- Signal processor
- Bioreceptor
- Display unit
Correct Answer: Bioreceptor
Q2. Which transduction principle measures current produced by redox reactions at an electrode surface?
- Optical
- Electrochemical
- Piezoelectric
- Thermal
Correct Answer: Electrochemical
Q3. An enzyme-based glucose biosensor primarily relies on which enzyme?
- Urease
- Glucose oxidase
- Acetylcholinesterase
- Peroxidase
Correct Answer: Glucose oxidase
Q4. Which immobilization technique involves physical entrapment of biomolecules within a polymer matrix?
- Covalent binding
- Adsorption
- Entrapment
- Cross-linking
Correct Answer: Entrapment
Q5. In an optical biosensor using surface plasmon resonance (SPR), the signal is based on which phenomenon?
- Mass change on a crystal
- Change in refractive index near the sensor surface
- Generation of electric current
- Heat produced by binding
Correct Answer: Change in refractive index near the sensor surface
Q6. Which characteristic describes the smallest analyte concentration that can be reliably distinguished from zero?
- Dynamic range
- Response time
- Limit of detection
- Specificity
Correct Answer: Limit of detection
Q7. A piezoelectric biosensor detects analyte binding by monitoring which parameter?
- Change in current
- Change in mass via frequency shift
- Change in light intensity
- Change in temperature
Correct Answer: Change in mass via frequency shift
Q8. Which bioreceptor type is most suitable for detecting specific DNA sequences?
- Enzymes
- Antibodies
- Nucleic acid probes
- Whole cells
Correct Answer: Nucleic acid probes
Q9. In electrochemical biosensors, which measurement mode monitors potential at zero current?
- Amperometry
- Voltammetry
- Potentiometry
- Impedance spectroscopy
Correct Answer: Potentiometry
Q10. Which immobilization method provides the strongest, most stable attachment of biomolecules to a sensor surface?
- Physical adsorption
- Covalent coupling
- Entrapment in gel
- Layer-by-layer assembly
Correct Answer: Covalent coupling
Q11. Which factor most directly affects biosensor selectivity?
- Transducer material
- Bioreceptor specificity
- Signal amplifier type
- Calibration algorithm
Correct Answer: Bioreceptor specificity
Q12. In an immunosensor, the primary molecular interaction exploited is between:
- Enzyme and substrate
- Antibody and antigen
- Complementary DNA strands
- Cell receptor and ligand
Correct Answer: Antibody and antigen
Q13. Which nanomaterial is commonly used to enhance electron transfer and surface area in electrochemical biosensors?
- Polystyrene beads
- Gold nanoparticles
- Cellulose fibers
- Glass microspheres
Correct Answer: Gold nanoparticles
Q14. What is the main advantage of integrating microfluidics with biosensors in pharmaceutical applications?
- Increased reagent consumption
- Improved sample throughput and reduced volumes
- Complex fabrication without benefits
- Lower sensitivity
Correct Answer: Improved sample throughput and reduced volumes
Q15. Which performance parameter describes how quickly a biosensor reaches a stable response after sample introduction?
- Limit of detection
- Response time
- Reproducibility
- Shelf life
Correct Answer: Response time
Q16. Which of the following is a common interference that can affect enzymatic biosensor readings in biological samples?
- Non-specific adsorption of proteins
- Ideal sample matrix
- Absolute absence of salts
- Perfect pH stability
Correct Answer: Non-specific adsorption of proteins
Q17. Which sensor regeneration strategy enables reuse of an antibody-based biosensor?
- Increasing temperature to denature antibody
- Reversible disruption of binding using mild elution buffer
- Permanent chemical modification of antigen
- Mechanical scraping of the surface
Correct Answer: Reversible disruption of binding using mild elution buffer
Q18. In impedimetric biosensors, monitoring which electrical property helps detect binding events?
- Optical absorbance
- Impedance or resistance changes
- Mass frequency only
- Temperature variation
Correct Answer: Impedance or resistance changes
Q19. For point-of-care pharmaceutical testing, which biosensor attribute is most critical?
- High maintenance complexity
- Portability and rapid results
- Large sample volume requirement
- Long stabilization time
Correct Answer: Portability and rapid results
Q20. Which of these is NOT typically classified as a bioreceptor?
- Enzymes
- Metal electrodes
- Antibodies
- Aptamers
Correct Answer: Metal electrodes
Q21. In pharmaceutical process monitoring, biosensors are particularly useful for:
- Measuring mechanical properties of tablets
- Real-time monitoring of metabolites or contaminants
- Replacing all chromatographic assays immediately
- Counting tablet weight only
Correct Answer: Real-time monitoring of metabolites or contaminants
Q22. Which detection mode measures current at a fixed potential and is common for enzyme biosensors?
- Amperometry
- Fluorometry
- Mass spectrometry
- Calorimetry
Correct Answer: Amperometry
Q23. Aptamers are attractive bioreceptors because they are:
- Protein-based and unstable
- Short synthetic nucleic acids with high specificity
- Always larger than antibodies
- Incapable of reversible binding
Correct Answer: Short synthetic nucleic acids with high specificity
Q24. Which approach improves biosensor sensitivity by increasing surface area for biomolecule attachment?
- Using flat glass only
- Nanostructuring electrode surfaces
- Reducing electrode active area
- Removing all surface functional groups
Correct Answer: Nanostructuring electrode surfaces
Q25. What role does a reference electrode play in potentiometric biosensors?
- Generates the primary signal
- Provides a stable potential for comparison
- Measures optical changes
- Acts as the bioreceptor
Correct Answer: Provides a stable potential for comparison
Q26. Which thermal effect is exploited in calorimetric biosensors to detect biochemical reactions?
- Change in refractive index
- Heat release or absorption during binding
- Mass gain on a crystal
- Electric current generation
Correct Answer: Heat release or absorption during binding
Q27. Which validation parameter ensures biosensor results are consistent across repeated measurements?
- Shelf life
- Reproducibility and precision
- Selectivity only
- Color of the device
Correct Answer: Reproducibility and precision
Q28. In nucleic-acid based biosensors, hybridization events are often detected by:
- Changes in electrical or optical signal due to duplex formation
- Direct measurement of enzyme activity
- Mass change on a quartz only
- Measuring blood pressure
Correct Answer: Changes in electrical or optical signal due to duplex formation
Q29. Which regulatory consideration is most relevant when implementing biosensors in pharmaceutical quality control?
- Device color aesthetics
- Analytical validation, traceability, and compliance with pharmacopeial standards
- Only academic publication is required
- Ignoring calibration records
Correct Answer: Analytical validation, traceability, and compliance with pharmacopeial standards
Q30. Which advancement most improves miniaturized biosensor integration for wearable drug monitoring?
- Bulkier power supplies
- Flexible electronics and low-power transduction
- Eliminating data connectivity
- Large reagent reservoirs
Correct Answer: Flexible electronics and low-power transduction
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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