Microimm 2500 Bacteriology Exam Questions With Verified Solutions

Microimm 2500 Bacteriology Exam Questions With Verified Solutions Prokaryotes - answersmallest, simplest organisms on Earth; most abundant; includes bacteria & archaea; lack nucleus and complex organelles four phases of bacterial growth - answerlag; log; stationary; death bacteria reproductive mechanism - answerbinary fission bacterial generation time - answertime between generations (time for one division) reason stationary phase exists - answerbacteria reach a point where resources are being used quickly enough that bacteria can no longer grow coccus - answersphere-shaped bacteria bacilli - answerrod-shaped bacteria spirillum - answerspiral-shaped bacteria obligate aerobe - answerrequires oxygen for growth obligate anaerobe - answeroxygen is toxic for growth facultative anaerobe - answercan use oxygen if present; grows without oxygen anyways aerotolerant anaerobe - answerdoesn't use oxygen but it isn't toxic microaerophile - answergrows best under low oxygen levels creator of the Gram Stain - answerHans Christian Gram gram stain procedure - answerstain with methyl violet; wash with iodine; remove colour with ethanol; counterstain with safranin gram positive bacteria colour - answerpurple gram negative bacteria colour - answerpink bacterial cell wall component determining Gram class - answerpeptidoglycan layer (thicker in G+) peptidoglycan - answerrigid structure that prevents osmotic lysis; glycan backbone that is peptide-crosslinked two components of glycan backbone - answern-acetylglucosamine & n-acetylmuramic acid lipopolysaccharide - answerendotoxin found in cell wall of G- bacteria; made of three components three parts of lipopolysaccharide - answerO-specific polysaccharide; core polysaccharide; lipid A lipid A - answercontains N-acetylglucosamine disaccharide and fatty acid groups (amphipathic); recognized by immune system (leads to septic shock) three functions of the cytoplasmic membrane - answerpermeability barrier; protein anchoring; energy conservation periplasm - answerfound only in G-; between inner and outer membranes; contains hydrolytic enzymes and transport proteins nucleoid - answersingle, haploid, circular chromosome not enclosed by a membrane plasmids - answerextrachromosomal, transmissible, genetic elements that are usually not required for growth purpose of plasmids - answerusually encodes for fitness factors commensalism - answerone organism benefits while the other is unaffected mutualism - answerboth organisms benefit parasitism - answerone organism benefits (usually the microbe) at the expense of the other (usually the host) virulence factors - answerfactors that help bacteria survive and contribute to disease flagella - answerstructure that allows some bacteria to be motile; clockwise rotation produces run, counterclockwise rotation produces tumble pili - answersurface structures allowing bacteria to adhere to surfaces capsules - answerusually produced from exopolysaccharides; provides protection from host immune system; used for vaccines, attachment, and biofilms biofilm - answera structure made up of exopolysaccharides containing microcolonies endospore - answerhighly differentiated cell formed inside the parent cell when exposed to stress; dormant stage that is highly resistant to heat, chemicals, and radiation