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Microbiology & Pharmacology

The Microbiology & Pharmacology category covers fundamental topics linking microorganisms and drug actions. It includes bacterial structure, viral mechanisms, antimicrobial agents, drug classifications, and therapeutic principles. Ideal for students preparing for medical entrance and licensing exams.

25 questions

Microbiology & Pharmacology

Which of the following are examples of codominance? I. A person with blood type AB II. A flower that displays a red and

AB blood type expresses both A and B antigens simultaneously, classic codominance. Spotted red-white flowers expressing both colors side by side also show codominance, unlike pink intermediate incomplete dominance or dominant-recessive masking where heterozygote resembles one homozygote.

Ref: Klug et al., Concepts of Genetics, 12th Edition, Chapter 3 Extensions of Mendelian Inheritance, discusses codominance examples including AB blood group expressing both antigens and spotted phenotypes versus incomplete and complete dominance, published by Pearson Education.

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Microbiology & Pharmacology

Which of the following choices are likely to change the allele frequencies of the indicated populations? I. A geographic

Geographic isolation creates founder effect and drift, altering allele frequencies in small isolated subsets. Predation selecting against homozygous dominants imposes directional selection changing genotype frequencies. Random mating alone maintains equilibrium without altering allele frequencies under Hardy-Weinberg conditions.

Ref: Futuyma, Evolutionary Biology, 4th Edition, Chapter 10 Genetic Drift and Natural Selection Mechanisms, explains geographic isolation causing founder effect and selective predation altering allele frequencies while random mating maintains Hardy-Weinberg equilibrium, published by Sinauer Associates.

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Microbiology & Pharmacology

A population of insects exists in which black coloration is dominant to white. If there are 64 black insects and 36 whit

White recessive phenotype frequency equals q squared, here 36 of 100 equals 0.36. Square root gives recessive allele q equals 0.6. Hardy-Weinberg principle allows allele estimation assuming random mating, large population, no selection or migration influence.

Ref: Hartl and Clark, Principles of Population Genetics, 4th Edition, Chapter 2 Hardy-Weinberg Principle and allele frequency calculation from recessive homozygote phenotype frequency square root to estimate q, published by Sinauer Associates.

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Microbiology & Pharmacology

What is the function of Chaperonins?

Chaperonins like GroEL-GroES form barrel-shaped oligomeric chambers providing isolated environment for polypeptide folding. ATP-driven conformational changes encapsulate misfolded intermediates, preventing aggregation and promoting correct native structure acquisition without information transfer.

Ref: Lehninger et al., Principles of Biochemistry, 8th Edition, Chapter 4 Protein Folding and Chaperones, describes chaperonins GroEL-GroES barrel complex facilitating ATP-dependent protein folding by preventing aggregation and isolating misfolded intermediates, published by Macmillan Learning.

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Microbiology & Pharmacology

Databases such as CATH and SCOP are used to identify:

CATH and SCOP classify proteins hierarchically by class, architecture, topology, and homologous superfamilies based on three-dimensional structures. They enable identification of structural families, evolutionary relationships, and detection of fold similarities beyond sequence homology for annotation.

Ref: Mount, Bioinformatics: Sequence and Genome Analysis, 2nd Edition, Chapter 9 Protein Structural Databases, explains CATH and SCOP hierarchical classification of protein structures into families superfamilies and folds for structural comparison, published by Cold Spring Harbor Laboratory Press.

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Microbiology & Pharmacology

RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is a conserved biological response to:

RNA interference is triggered by long double-stranded RNA recognized by Dicer, which cleaves it into small interfering RNAs. These siRNAs guide Argonaute in RISC to degrade complementary mRNA, serving as conserved antiviral defense and endogenous gene regulation mechanism.

Ref: Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 8 Control of Gene Expression and RNA Interference Pathway triggered by double-stranded RNA processed by Dicer into siRNA guiding RISC, published by Garland Science.

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Microbiology & Pharmacology

HbS (Sickle Cell Anaemia) is a result of:

Sickle hemoglobin results from A to T transversion in sixth codon of beta-globin gene, changing GAG glutamic acid to GTG valine. Transversion replaces purine with pyrimidine, creating hydrophobic patch causing polymerization under deoxygenation and characteristic sickling.

Ref: Hartl et al., Genetics: Analysis of Genes and Genomes, 9th Edition, Chapter 14 Gene Mutations and Molecular Basis of Sickle Cell Transversion Mutation A to T leading to glutamic acid to valine substitution, published by Jones and Bartlett Learning.

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Microbiology & Pharmacology

Statement I: Aspirin and paracetamol belong to the class of non-narcotic analgesics. Statement II: Aspirin inhibits the

Both aspirin and paracetamol are non-narcotic analgesics acting via cyclooxygenase inhibition without opioid receptor involvement. Aspirin irreversibly acetylates COX, blocking prostaglandin E2 and thromboxane synthesis, thereby reducing inflammation, pain, and fever effectively.

Ref: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition, Chapter 36 Nonsteroidal Anti-inflammatory Drugs and Acetaminophen, discusses aspirin and paracetamol as non-narcotic analgesics inhibiting prostaglandin synthesis via COX inhibition reducing pain inflammation, published by

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Microbiology & Pharmacology

Which of the following is NOT a feature of flow cytometry?

In flow cytometry hydrodynamic focusing uses sheath fluid surrounding sample core stream to align cells single file through laser interrogation. The core stream contains cells, not just sheath fluid, enabling light scatter measurement and fluorescence emission detection for analysis.

Ref: Murphy and Weaver, Janeway's Immunobiology and Kuby Immunology, 8th Edition, Chapter 22 Experimental Systems and Flow Cytometry, describes hydrodynamic focusing with sample core stream containing cells surrounded by sheath fluid for single-file laser analysis, published by W.H. Freeman.

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Microbiology & Pharmacology

Which of the following is the most probable explanation for higher lability of RNA than DNA?

RNA possesses a 2'-hydroxyl group on ribose that acts as internal nucleophile, facilitating intramolecular transesterification and backbone cleavage under alkaline conditions. DNA lacks this hydroxyl, making its phosphodiester bonds significantly more stable against hydrolysis.

Ref: Lehninger et al., Principles of Biochemistry, 8th Edition, Chapter 8 Nucleic Acid Chemistry and Stability, explains 2'-hydroxyl group in ribose causing RNA lability to alkaline hydrolysis via intramolecular transesterification unlike deoxyribose DNA, published by Macmillan Learning.

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Microbiology & Pharmacology

RPMI 1640 growth medium used for cell culture contains all of the following, EXCEPT:

RPMI 1640 was formulated by Moore at Roswell Park for lymphoid cells, containing inorganic salts, glucose, amino acids, vitamins, and buffers, but no serum, proteins, or growth factors. Supplementation with fetal bovine serum provides necessary growth factors for proliferation.

Ref: Freshney, Culture of Animal Cells: A Manual of Basic Technique and Specialized Applications, 7th Edition, Chapter 9 Defined Media and Supplements, describes RPMI 1640 composition containing salts glucose vitamins but requiring serum supplementation for growth factors, published by Wiley-Blackwell.

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Microbiology & Pharmacology

Acid guanidinium thiocyanate-phenol-chloroform extraction (AGPC) is an extraction method is used for isolation of:

Acid guanidinium thiocyanate-phenol-chloroform, developed by Chomczynski and Sacchi, simultaneously lyses cells and denatures RNases. Under acidic pH, RNA partitions to aqueous phase while DNA and proteins separate to interphase and organic phase, yielding all three.

Ref: Sambrook and Russell, Molecular Cloning: A Laboratory Manual, 4th Edition, Chapter 7 Isolation of RNA by Acid Guanidinium Thiocyanate Phenol Chloroform Extraction Method of Chomczynski and Sacchi for simultaneous RNA DNA protein recovery, published by Cold Spring Harbor Laboratory Press.

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