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General Microbiology & Vector Biology

This category covers fundamental concepts in microbiology, including the structure, classification, and physiology of microorganisms, as well as the biology of disease‑causing vectors such as insects and arthropods.

25 questions

General Microbiology & Vector Biology

Which viruses undergo genetic drift and genetic shift

Influenza A virus undergoes antigenic drift via point mutations in HA and NA due to error-prone RNA polymerase, and antigenic shift via reassortment of segmented genome when two strains co-infect cell. This dual variation causes seasonal epidemics and pandemics, unlike polio, hepatitis or dengue which lack segmented reassortment.

Ref: Flint S.J., Enquist L.W., Racaniello V.R., Principles of Virology, 4th Edition, Chapter on Influenza Virus Evolution, explains antigenic drift and shift mechanisms due to segmented RNA genome reassortment and mutation, published by ASM Press American Society for Microbiology.

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General Microbiology & Vector Biology

Given below are Assertion (A) and Reasoning (R) Assertion (A) : The Western Hemisphere was eliminated of polio viruses b

IPV introduced 1955 induced humoral immunity, followed by OPV 1961 providing intestinal immunity and community spread. Mass campaigns across Americas achieved high coverage interrupting transmission. PAHO declared polio eliminated in Western Hemisphere in 1994 certification, validating combined vaccine strategy's success from 1955-1963 rollout.

Ref: Centers for Disease Control and Prevention, Progress toward global polio eradication historical reports, and Plotkin's Vaccines 7th Edition Chapter on Poliovirus Vaccines, details IPV and OPV introduction 1955-1963 leading to elimination in Americas by 1990-1994, published by Elsevier and CDC Atlant

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General Microbiology & Vector Biology

Given below are Assertion (A) and Reasoning (R) Assertion (A) : The level of efficacy of inactivated viral vaccine diffe

Inactivated viral vaccines show variable efficacy due to differing virus biology, antigen stability and adjuvant needs. They are produced in diverse substrates like eggs, Vero cells or diploid fibroblasts and inactivated by formalin or beta-propiolactone, causing substrate-related immunogenicity and purification differences that explains efficacy variation.

Ref: Plotkin S.A., Orenstein W.A., Offit P.A., Plotkin's Vaccines, 7th Edition, Chapter 8, Inactivated Viral Vaccines Production, discusses varying cell substrates and inactivation methods influencing vaccine efficacy and immunogenicity, published by Elsevier Saunders.

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General Microbiology & Vector Biology

Given below are two statements Statement I : Both adult male and female feed on blood Statement II : Both adult male and

Male and female mosquitoes both require sugar from nectar for energy and survival, taken via crop. Only females are anautogenous needing blood for egg development; males never blood-feed. Thus Statement I claiming both sexes blood-feed is incorrect, while Statement II about universal nectar feeding is true.

Ref: Foster W.A., Mosquito sugar feeding and reproductive energetics, Annual Review of Entomology, 1995, Chapter on Mosquito Biology, and Clements A.N., The Biology of Mosquitoes, describes both sexes feeding on nectar sugar while only females take blood, published by Annual Reviews and CABI.

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General Microbiology & Vector Biology

Which of the chemical reagent would be most suitable to isolate DNA/RNA/Protein together from same sample

TRIzol contains guanidinium thiocyanate and phenol enabling simultaneous isolation of RNA, DNA and protein from single sample via phase separation. After chloroform addition, aqueous phase yields RNA, interphase DNA and organic phase protein, superior to phosphate buffer, water or ethanol alone.

Ref: Chomczynski P. and Sacchi N., Single-step method of RNA isolation by acid guanidinium thiocyanate phenol chloroform extraction, Analytical Biochemistry, 1987, and Thermo Fisher TRIzol Manual, describe method for combined DNA RNA protein isolation, published by Elsevier.

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General Microbiology & Vector Biology

Find correct statement

Insects possess robust innate immunity lacking classical adaptive memory, immunoglobulins and RAG-mediated recombination. They rely on Toll, IMD pathways, antimicrobial peptides, hemocyte phagocytosis and melanization. No lymphocytes or clonal expansion occurs, clearly distinguishing from vertebrate combined innate-adaptive immunity.

Ref: Hoffmann J.A., The immune response of Drosophila, Nature 2003 review; and Janeway C.A. et al., Immunobiology, 9th Edition, Chapter on Innate Immunity in Invertebrates, states insects carry innate immunity without adaptive immunity, published by Nature and Garland Science.

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General Microbiology & Vector Biology

For generating insect vector genome data, which is essential and primary requirement

Whole genome sequencing fundamentally requires high molecular weight genomic DNA isolation. Despite transcriptomics using RNA, genome assembly needs DNA for library preparation, long-read and short-read sequencing. Protein sequencing cannot provide nucleotide genome information essential for vector genome projects.

Ref: Green M.R. and Sambrook J., Molecular Cloning: A Laboratory Manual, 4th Edition, Chapter on Genomic DNA Isolation and Genomic Libraries, describes DNA isolation as primary requirement for genome sequencing, published by Cold Spring Harbor Laboratory Press.

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General Microbiology & Vector Biology

For studying insect spermatogenesis process, which target organ needs to be focused

Spermatogenesis occurs within testes of male reproductive system. Follicles contain germline stem cells undergoing mitosis, meiosis and spermiogenesis within cysts supported by somatic cells. Therefore male gonads are targeted for staging, chromosome spreads and transcriptomic analysis, not female organs or excretory tubules.

Ref: Chapman R.F., The Insects: Structure and Function, 5th Edition, Chapter on Reproductive System, details testis structure and spermatogenesis process in insects, and Giese chapter on insect spermatogenesis, published by Cambridge University Press.

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General Microbiology & Vector Biology

Which insect of the following serves as best model for genetic studies

Drosophila melanogaster is premier genetic model due to short 10-day life cycle, high fecundity, polytene chromosomes and low diploid number 8. Morgan's pioneering linkage studies Nobel Prize and modern GAL4-UAS system enable functional genetics, unmatched by grasshopper, cockroach or mosquito.

Ref: Hartl D.L. and Jones E.W., Genetics: Analysis of Genes and Genomes, 8th Edition, Chapter on Model Organisms, and Ashburner M. et al., Drosophila: A Laboratory Handbook, discuss Drosophila melanogaster as ideal genetic model, published by Jones and Bartlett and Cold Spring Harbor Press.

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General Microbiology & Vector Biology

What is the best feed source for mosquito larva

Mosquito larvae are filter feeders grazing on microorganisms in aquatic habitats. Bacteria, algae, protozoa and yeasts provide essential proteins and sterols for development. Sugar and minerals alone are insufficient, while microbial biofilms determine larval nutrition, growth rate and adult fitness.

Ref: Merritt R.W. et al., Feeding behavior and nutrient impact on mosquito larvae, Annual Review of Entomology, 1992, and Clements A.N., The Biology of Mosquitoes, Chapter on Larval Nutrition, discuss microbes as primary food source, published by Annual Reviews and CABI.

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General Microbiology & Vector Biology

Which of the following is responsible for cellular immunity in insects

Cellular immunity in insects is mediated by hemocytes circulating in haemolymph. Plasmatocytes and granulocytes perform phagocytosis, encapsulation and nodule formation against invaders. Fat body mainly humoral, while salivary gland and midgut are digestive, not primary cellular immune effectors.

Ref: Lavine M.D. and Strand M.R., Insect hemocytes and their role in immunity, Insect Biochemistry and Molecular Biology, 2002, and Kuby Immunology 8th Edition Chapter on Innate Immunity describes insect hemocyte-mediated cellular defenses, published by Elsevier and W.H. Freeman.

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General Microbiology & Vector Biology

Which of the following is component of the circulatory system in insects

Insect circulatory system is open, with dorsal vessel comprising heart and aorta pumping haemolymph through hemocoel. Haemolymph carries nutrients, hormones and hemocytes but not oxygen, bathing organs directly. Fat body, thorax and abdomen are structural regions, not circulatory components.

Ref: Chapman R.F., The Insects: Structure and Function, 5th Edition, Chapter 11, Circulatory System, describes haemolymph composition and open circulation via dorsal vessel and hemocoel, published by Cambridge University Press.

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