BIOS 242 Week 2 Microbiology Exam – 250 Questions on Microscopy, Staining, Microbial Growth & Culture Techniques – 2026

This document contains a comprehensive 250-question Week 2 exam review for BIOS 242 Microbiology, presented in a structured question-and-answer format with expert-verified responses. The content begins with microscopy fundamentals, including wavelength, magnification, resolution, contrast, and the purpose of staining to enhance visualization (pages 1–2). It thoroughly reviews bright-field, dark-field, phase-contrast, differential interference contrast, fluorescence, confocal, electron, and probe microscopes (scanning tunneling and atomic force), as well as compound microscope components such as ocular lens, objective lens, condenser, diaphragm, illuminator, and oil immersion lens. Extensive staining concepts are covered, including heat fixation, acidic versus basic dyes, simple stains (crystal violet, safranin, methylene blue), differential stains (Gram stain, acid-fast, endospore, histological stains), special stains, and staining for electron microscopy using heavy metals (pages 7–8). Taxonomy principles are also reviewed, including binomial nomenclature, phylogenetic hierarchy, the three domains (Bacteria, Archaea, Eukarya), and identification methods such as biochemical tests, serological testing, phage typing, nucleic acid analysis, and dichotomous keys (pages 8–10). The document further examines microbial nutrition and metabolism (autotrophs vs heterotrophs, phototrophs vs chemotrophs, lithotrophs vs organotrophs), oxygen requirements (obligate aerobes, obligate anaerobes, facultative anaerobes, aerotolerant anaerobes, microaerophiles), environmental factors affecting growth (temperature classifications, pH ranges, osmotic and hydrostatic pressure), microbial relationships (antagonism, synergism, symbiosis, quorum sensing, biofilms), and culture methods (streak plate, pour plate, defined vs complex media, selective and differential media). Growth phases (lag, log, stationary, death), generation time, chemostats, and microbial counting methods (viable plate count, serial dilution, flow cytometry, membrane filtration, most probable number, turbidity) are also comprehensively reviewed (pages 16–21). The material aligns closely with Microbiology: An Introduction by Tortora, Funke, and Case, a standard textbook used in BIOS 242 courses. It reflects key laboratory and lecture concepts emphasized in early-semester microbiology, including microscopy techniques, staining differentiation, metabolic classifications, environmental growth requirements, and quantitative microbial analysis. This document is particularly relevant for: Students enrolled in BIOS 242 Microbiology Pre-nursing and allied health students Biology and health science majors Students preparing for Week 2 microbiology exams Learners reviewing laboratory microscopy and culture techniques It serves as a structured, exam-focused study guide designed to reinforce microscopy principles, staining methods, microbial classification, metabolic diversity, environmental adaptations, culture techniques, and microbial growth measurement. Keywords: BIOS 242 Week 2 exam microscopy types bright field dark field compound microscope parts oil immersion resolution Gram stain procedure acid fast stain endospore stain green fluorescence confocal microscopy electron microscope vacuum probe microscopes STM AFM microbial growth phases lag log stationary death phase generation time bacteria selective vs differential media streak plate technique serial dilution viable plate count flow cytometry counting autotroph heterotroph differences obligate anaerobes facultative anaerobes quorum sensing biofilms