Ch 4 – Microbiology Test Questions – Flashcards
Unlock all answers in this set
Unlock answersquestion
| characteristics of prokaryotes |
answer
| -DNA not enclosed in a membrane -DNA not associated with histones -no membrane bound organelles -cell wall of peptidoglycan -divide by binary fission -bacteria and archea |
question
| 3 basic shapes |
answer
| cocci (spheres), bacilli (rods), spiral |
question
| arrangements of cocci |
answer
| -diplococci -streptococci -tetrad -sarcinae -staphylococci |
question
| streptococci |
answer
| chains |
question
| tetrad |
answer
| group of 4 cocci |
question
| sarcinae |
answer
| group of 8 cocci |
question
| staphylococci |
answer
| grapelike |
question
| types of bacilli |
answer
| -diplobacilli -streptobacilli -coccobacilli |
question
| types of spiral |
answer
| -vibrio -spirillum -spirochete |
question
| vibrio |
answer
| curved rods |
question
| spirillum |
answer
| helical shape (use flagella) |
question
| spirochete |
answer
| helical and flexible (axial filaments) |
question
| 3 other shapes |
answer
| -star -rectangle -triangle |
question
| star |
answer
| stella |
question
| rectangular |
answer
| haloarcula |
question
| triangular |
answer
| angulomicrobium |
question
| external structures to the cell wall |
answer
| -glycocalyx -flagella -pili/fimbriae |
question
| glycocalyx |
answer
| -general term to describe substances that surround the cell -viscous, sticky, gelatinous polymer of polysaccharides/polypeptides or both -capsule (organized tight) -slime layer(loose) |
question
| functions of glycocalyx |
answer
| -act as a barrier to toxic hydrophobic molecules (detergents) -can enable adherence to other bacteria or host tissue (biofilms) -major virulence factor due to its weak antigenic and antiphagocytic properties |
question
| flagella and types |
answer
| -composed of helically coiled proteins (flagellin) -peritrichous -monotrichous and polar -lophotrichous and polar -amphitrichous |
question
| peritrichous |
answer
| distributed over entire cell |
question
| monotrichous and polar |
answer
| single flagellum at one pole |
question
| lophotrichous and polar |
answer
| many flagella at one pole |
question
| amphitrichous |
answer
| flagella at both poles |
question
| flagella movement |
answer
| -driven by rotary engine composed of proteins located at flagellum's anchor point on the inner cell membrane (basal body) -powered by proton motive force |
question
| pili/fimbriae |
answer
| -thin protein tubes originating from plasma membrane -found in all gram negative bacteria |
question
| pili |
answer
| -shaft composed of pilin -involved in motility -bring bacteria together and allow transfer of DNA (conjugation) |
question
| fimbriae |
answer
| -can occur at poles or over entire surface -promote attachment to other bacteria and host -virulence factor -ex. E. coli colonization -N. gonorihoeae urinary infection |
question
| the cell wall and functions |
answer
| -contains semi rigid, tight knit, molecular complex of peptidoglycan(NAG,NAM,peptides) -protects inside of cell from detrimental changes in the outside environment -prevents cell from rupturing in hypotonic conditions -maintains shape -provides ligands(binds to receptors) for adherence -essential structure for cell viability |
question
| NAM and NAM |
answer
| -linked in rows of 10-65 sugars -attached to peptide chain of 4 amino acids (direct and cross linked) |
question
| The gram stain |
answer
| -named after Hans Christian Gram (1884) -one of the most important techniques in microbio -based on ability of bacteria cell wall to retain primary crystal violet dy during solvent treatment |
question
| Gram stain steps |
answer
| -apply crystal violet -apply iodine (mordant) -decolorize with alcohol -apply safranin (counterstain) |
question
| Gram + stain mechanism |
answer
| -high peptidoglycan -low lipid -pores shrink from alcohol -CVI complex retained |
question
| Gram - stain mechanism |
answer
| -low peptidoglycan -high lipid -dissolution of lipid membrane from alcohol -CVI complex washes out -cell takes up counterstain |
question
| Gram + cell wall characteristics |
answer
| -thick peptidoglycan (20-80nm) -contains teichoic acids (wall and lipo) -contains alcohol group (glycerol,ribitol) and phosphate group -may be involved in regulating flow of cations -important surface antigens involved in adherence |
question
| Gram - cell wall characteristics |
answer
| -thin peptidoglycan (7-8nm) -no teichoic acids -possesses outer membrane -lipoprotein bind peptidoglycan to outer membrane |
question
| outer membrane |
answer
| -LPS -lipoproteins -phospholipids -porins |
question
| LPS |
answer
| -lipid A -core polysaccharide -O antigen |
question
| lipid A |
answer
| -basic component -endotoxin activity |
question
| core polysaccharide |
answer
| -branched 9-12 sugars -structural |
question
| O antigen |
answer
| -50-100 repeating saccharide units -allows serotype distinction |
question
| mycoplasma |
answer
| -have no cell wall -plasma membrane contains sterols |
question
| Archea |
answer
| -may lack cell wall or are composed of polysaccharides and proteins -pseudomurein instead of peptidoglycan |
question
| plasma membrane |
answer
| -thin semi permeable membrane composed of phospholipid bilayer -polar ends form innermost and outermost -peripheral proteins found at innner or outer surface -integral proteins span membrane or are channels with a pore (transmembrane proteins) |
question
| functions of plasma membrane |
answer
| -selective semi permeable membrane that determines what goes on in and out of organism -breakdown of nutrients -production of energy (ATP) |
question
| cytoplasm |
answer
| -gel like substance -80% water -contains proteins, carbs, lipids, inorganic ions. low MW compounds |
question
| major structures of cytoplasm |
answer
| -nucleoid -plasmids -ribosomes -inclusions |
question
| nucleoid |
answer
| -long single molecule of double stranded helical supercoiled DNA |
question
| plasmids |
answer
| -small molecules of double stranded helical non chromosomal DNA -code for proteins not coded by nucleoid (antibiotic resistance, exotoxins) |
question
| ribosomes |
answer
| -composed of rRNA and protein -composed of two subunits with densities of 30S and 50S -two subunits combine during protein synthesis to make 70S |
question
| inclusions |
answer
| -reserve deposits -may be starch glycogen, lipids, sulfur, phosphate -bacteria live in competitive environment where nutrients are in short supply so they store up whenever possible -gas vacuoles are hollow cylinders that maintain buoyancy |
question
| endospores |
answer
| -resistant structures formed by Gram + bacteria under adverse conditions -most resistant life from known -able to survive 100 degrees C for long periods -reisistant to UV light, drying up, and harmful chemicals -some disease organisms like anthrax and botulism form spores that reside in soil -size shape and location are genetic characteristics |
question
| formation of endospores |
answer
| -spore septum begins to isolate newly replicated DNA and a small portion of cytoplasm -Plasma membrane starts to surround DNA, cytoplasm, and membrane isolated in step 1 -spore septum surrounds isolated portion forming an forespore -peptidoglycan layer forms between membranes -spore coat forms -endospore is freed from cell |
question
| NAG |
answer
| N-acetylglucosamine |
question
| NAM |
answer
| N-acetylmuramic acid |
