Microbial applications in environmental monitoring MCQs With Answer

Microbial applications in environmental monitoring MCQs With Answer

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Introduction:

This collection of multiple-choice questions focuses on microbial applications in environmental monitoring, tailored for M.Pharm students studying Advanced Pharmaceutical Biotechnology. The questions cover core concepts such as microbial biosensors, molecular detection methods (qPCR, metagenomics), microbial source tracking, bioindicators, bioremediation strategies, and toxicity bioassays. Emphasis is placed on practical interpretation of data, method selection, and limitations relevant to monitoring water, soil, and air quality. Each question is designed to deepen understanding of microbial tools used to detect pollutants, pathogens, and ecological change, preparing students for research, regulatory tasks, and applied environmental biotechnology roles.

Q1. Which characteristic best defines a microbial bioindicator used for monitoring freshwater pollution?

  • Ability to grow rapidly in any environmental condition
  • Sensitivity to specific pollutants with a predictable response
  • High metabolic diversity irrespective of pollutant presence
  • Resistance to multiple antibiotics

Correct Answer: Sensitivity to specific pollutants with a predictable response

Q2. What is the primary advantage of whole-cell microbial biosensors compared with chemical sensors in environmental monitoring?

  • They always provide quantitative concentration data without calibration
  • They can report bioavailable fraction and biological effect of contaminants
  • They are immune to environmental interferences such as temperature
  • They have unlimited operational lifetime in the field

Correct Answer: They can report bioavailable fraction and biological effect of contaminants

Q3. Which reporter gene is commonly used in environmental bacterial biosensors to generate a luminescent signal without requiring external substrates?

  • lacZ (beta-galactosidase)
  • luc (firefly luciferase)
  • luxCDABE (bacterial luciferase operon)
  • gfp (green fluorescent protein)

Correct Answer: luxCDABE (bacterial luciferase operon)

Q4. In the context of environmental monitoring, which statement best contrasts enzyme-based biosensors and whole-cell biosensors?

  • Enzyme biosensors measure community-level responses; whole-cell biosensors measure single-enzyme activity
  • Enzyme biosensors require living organisms to function; whole-cell biosensors use isolated proteins
  • Enzyme biosensors typically offer higher substrate specificity but lack responses to bioavailability and toxicity
  • Whole-cell biosensors cannot be engineered to detect specific analytes

Correct Answer: Enzyme biosensors typically offer higher substrate specificity but lack responses to bioavailability and toxicity

Q5. Which molecular technique is most appropriate for quantitative detection of fecal pollution markers in environmental water samples?

  • Plate counting on selective media
  • Quantitative PCR (qPCR) targeting specific DNA markers
  • Metagenomic shotgun sequencing without controls
  • Fluorescent in situ hybridization (FISH) using universal probes

Correct Answer: Quantitative PCR (qPCR) targeting specific DNA markers

Q6. Which microbial genetic marker is widely used in microbial source tracking (MST) to indicate human fecal contamination?

  • mcrA gene (methanogen marker)
  • HF183 Bacteroides 16S rRNA marker
  • nifH gene (nitrogen fixation marker)
  • blaTEM gene (beta-lactamase antibiotic resistance)

Correct Answer: HF183 Bacteroides 16S rRNA marker

Q7. When comparing 16S rRNA amplicon sequencing to shotgun metagenomics for environmental monitoring, what is a primary advantage of shotgun metagenomics?

  • Lower cost per sample for high-throughput studies
  • Provides taxonomic profiles without any bioinformatic processing
  • Enables detection of functional genes, resistomes, and viruses in addition to taxonomy
  • Requires less DNA input and no library preparation

Correct Answer: Enables detection of functional genes, resistomes, and viruses in addition to taxonomy

Q8. Which limitation of culture-based methods is most relevant when monitoring environmental pathogens?

  • They detect DNA from dead cells giving false positives
  • They underestimate diversity because many organisms are viable but non-culturable
  • They always overestimate viable counts due to selective enrichment
  • They provide immediate results within minutes

Correct Answer: They underestimate diversity because many organisms are viable but non-culturable

Q9. In bioremediation practice, what is the main difference between bioaugmentation and biostimulation?

  • Bioaugmentation introduces nutrients; biostimulation adds specific pollutant-degrading microbes
  • Bioaugmentation involves physical removal of contaminants; biostimulation uses chemical neutralization
  • Bioaugmentation adds specialized microbial strains; biostimulation enhances native microbial activity via nutrient or electron donor addition
  • Bioaugmentation relies on sunlight-driven processes; biostimulation uses anaerobic digestion only

Correct Answer: Bioaugmentation adds specialized microbial strains; biostimulation enhances native microbial activity via nutrient or electron donor addition

Q10. Which microbial process is commonly exploited in monitoring and remediation of heavy metals due to reversible binding on cell surfaces?

  • Biomagnification
  • Biosorption
  • Biotransformation to volatile organic compounds
  • Enzymatic mineralization

Correct Answer: Biosorption

Q11. Why are biofilm communities often targeted in environmental monitoring programs?

  • Biofilms always indicate low pollutant levels because they exclude contaminants
  • Biofilms integrate temporal exposure and accumulate pollutants and microorganisms, reflecting long-term conditions
  • Biofilms cannot be analyzed with molecular methods
  • Biofilms are homogeneous and represent single-species populations

Correct Answer: Biofilms integrate temporal exposure and accumulate pollutants and microorganisms, reflecting long-term conditions

Q12. How can microbial fuel cells (MFCs) be used as sensors for environmental monitoring?

  • They convert all types of radiation into electrical signals
  • They generate electricity proportional to the metabolic oxidation of organic pollutants, enabling indirect pollutant detection
  • They are only used to power remote sensors and not for sensing
  • They directly sequence microbial genomes to identify contaminants

Correct Answer: They generate electricity proportional to the metabolic oxidation of organic pollutants, enabling indirect pollutant detection

Q13. Which test uses the bioluminescent bacterium Vibrio fischeri to assess acute toxicity of environmental samples?

  • Mutagenicity Ames test
  • Microtox assay
  • Algal growth inhibition test
  • LD50 mammalian assay

Correct Answer: Microtox assay

Q14. Which soil enzyme activity is commonly measured as an indicator of overall microbial metabolic activity and soil health?

  • Dehydrogenase activity
  • Cellulase only
  • Laccase exclusively
  • Alpha-amylase in isolation

Correct Answer: Dehydrogenase activity

Q15. What is a primary advantage of passive sampling devices in microbial environmental monitoring?

  • They provide instantaneous concentration snapshots but cannot integrate over time
  • They require continuous power and complex electronics for deployment
  • They accumulate analytes or microbes over time, offering time-integrated exposure data with low maintenance
  • They sterilize samples in situ to prevent contamination

Correct Answer: They accumulate analytes or microbes over time, offering time-integrated exposure data with low maintenance

Q16. Which approach is most appropriate for monitoring environmental antibiotic resistance dissemination?

  • Measuring only total heterotrophic plate counts
  • Quantifying specific resistance genes (e.g., bla, sul, tet) by qPCR and combining with metagenomics for context
  • Relying solely on culture of fastidious pathogens
  • Visual inspection of water color and turbidity

Correct Answer: Quantifying specific resistance genes (e.g., bla, sul, tet) by qPCR and combining with metagenomics for context

Q17. Which international standards or agencies commonly provide protocols for microbial water quality testing relevant to pharmaceuticals and environmental monitoring?

  • ISO and EPA standard methods
  • Only local university protocols with no international guidance
  • World Trade Organization (WTO) microbiology guidelines
  • ASTM guidelines exclusively for air quality

Correct Answer: ISO and EPA standard methods

Q18. Regarding limits of detection and sensitivity, which statement correctly compares qPCR and culture-based enumeration for pathogen monitoring?

  • qPCR can detect both culturable and non-culturable organisms and often has lower detection limits, but it cannot by itself distinguish viability
  • Culturing always has lower detection limits than qPCR and detects DNA from dead cells
  • qPCR requires organisms to be alive to produce a signal
  • Culturing provides rapid results within minutes compared to qPCR

Correct Answer: qPCR can detect both culturable and non-culturable organisms and often has lower detection limits, but it cannot by itself distinguish viability

Q19. What is the primary biosafety concern when deploying genetically modified microbial biosensors in open environmental monitoring?

  • They always increase nutrient levels in the environment
  • Horizontal gene transfer of engineered traits to native microbes and ecological impact from release
  • They cannot be detected after release so they are safe
  • They will immediately die in all environmental conditions

Correct Answer: Horizontal gene transfer of engineered traits to native microbes and ecological impact from release

Q20. Which microbial indicator approach is most appropriate for early detection and monitoring of harmful algal blooms (HABs) that produce cyanotoxins?

  • Counting total heterotrophic bacteria as a proxy for cyanobacteria presence
  • Targeted molecular assays for cyanobacterial toxin genes (e.g., microcystin synthetase mcy genes) combined with pigment and toxin measurements
  • Measuring only dissolved oxygen as the sole indicator
  • Visual assessment of fish health without chemical or molecular tests

Correct Answer: Targeted molecular assays for cyanobacterial toxin genes (e.g., microcystin synthetase mcy genes) combined with pigment and toxin measurements

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