Microbiology Exam One Study Guide
Microbiology Exam One Study Guide 3209
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This 15 page Study Guide was uploaded by Kathryn Bielecki on Thursday October 6, 2016. The Study Guide belongs to 3209 at Bellevue College taught by Naomi Jones in Fall 2016. Since its upload, it has received 97 views. For similar materials see Bio 260 in Biology at Bellevue College.
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Date Created: 10/06/16
Microbiology Exam One Study Guide What is a negative stain? -colors background, not bacteria -little shrinkage (no heat-ﬁxing), can see cell size/shape 1) put india ink droplet @ one end of slide 2) use needle to transfer/mix bacteria into droplet 3) use another slide to spread ink across side 4) clean spreader slide & air-dry smeared slide 5) view under oil immersion What is a simple positive stain? -color bacteria, not background -heat-ﬁxing makes bacteria adhere to slide, kills it, & bacteria absorbs stain better 1) use wax pencil to draw circle on bottom of slide 2) use loop to add distilled water w/ loop on top of slide 3) use needle to mix in bacteria 4) air-dry slide, then heat-ﬁx 5) ﬂood w/ methylene blue (1 min) 6) rinse, blot, view w/ oil immersion What is a Gram stain? -ﬁrst step in identifying bacteria, using cell wall -Gram (+) bacteria = thick peptidoglycan (stain purple) -Gram (-) = thin pep. & outer membrane (stain pink) 1) start w/ simple positive smear, air-dried & heat-ﬁxed 2) use crystal violet primary stain (1 min) 3) rinse 4) use iodine mordant (1 min) 5) rinse 6) use 95% alcohol, drop until runs clear 7) rinse 8) use safranin counterstain (20 sec's) 9) rinse, blot, view w/ oil immersion What is an endospore stain? -endospores from soil bacteria; w/ nutrient depletion, vegetative cells sporulate -their spore coat protects against radiation, antibiotics, dyes -calcium & dipicolinic acid make them heat resistant 1) start w/ simple positive smear, air-dried & heat-ﬁxed 2) place over steam, add paper towel & malachite green (5 min) 3) cool off then rinse (30 sec's) 4) use safranin (20 sec's) 5) rinse, blot, view w/ oil immersion What is an acid-fast stain? -acid-fast bacteria are ones that if stained, cannot be removed w/ acid-alcohol (due to mycolic acid in wall) -this type of staining helps determine pathogens (tuberculosis, leprosy) 1) start w/ simple positive smear (w/ an acid-fast bacteria & other random bacteria), air-dried & heat-ﬁxed 2) place over steam, add paper towel & carbolfuchsin (5 min) 3) cool off then rinse (30 sec's) 4) acid-alcohol drops till runs clear 5) rinse 6) brilliant green (30 sec's) 7) rinse, blot, view w/ oil immersion What is hydrolysis? -the splitting of larger molecules with the addition of water What is an induced enzyme? -enzymes produced only when needed What is an exoenzyme? -enzymes secreted by a cell into the environment What is a constitutive enzyme? -enzymes produced all the time Why do bacteria produce exoenzymes? -to break down large nutrients for their own consumption How will you know that the bacteria has successfully produced their exoenzyme? -starch agar: clear halo -milk agar: clear halo -spirit blue agar: clear/light blue halo -DNA agar: clear halo -tryptophan broth: red layer -urease broth: bright pink layer -bile: dark brown layer What does reagent mean? -a chemical that detects whether or not the enzymes that hydrolyze the nutrients were secreted by the cells Who was Anton van Leeuwenhoek (1600)? -father of microscope (drapery merchant) -1st person to ever see a microbe, but destroyed his microscopes -his lens magniﬁed up to 300x Who was Francesco Redi (1600)? -found that maggots didn't generate from meat alone w/out an air source -disproved spontaneous generation Who was John Needham (1700)? -thought that boiling killed everything; then his beef broth grew microbes after being boiled -provided support for spontaneous generation (thought the beef broth grew the microbes itself...) Who was Lazzaro Spallanzani (1700)? -boiled 2 ﬂasks of broth, one lidded and one open; lidded one was sterile and the other had microbes (killed the vegetative force by taking away air supply(?) Who were Franz Schultze & Theodor Schwann (1800)? -by heating air, killed off vegetative force(?), coiled tube let air inside the broth but it remained sterile & microbes did not grow Who was Theodor Schwann (1800)? -experiment w/ Schultze -created Cell Theory: all animal tissues are made of cells Who was Louis Pasteur (1800)? -showed microbes caused fermentation & spoilage -used swan-necked ﬂask to disprove spontaneous generation (broth boiled, left open w/ swan neck for air source, no microbes grow) -developed pasteurization for killing microbes -introduced Germ Theory of Disease (1 microbe causes 1 disease) Who was John Tyndall (1800)? -invented Tyndallization to kill heat-resistant microbes (which were really endospores) -process used boiling/cooling cycle to kill endospores Who was Ferdinand Cohn (1800)? -ﬁgured out that the heat resistant microbes were actually endospores (ﬁnal overthrow of Spontaneous Generation) Who was Robert Koch (1800)? -father of microbiology, made aseptic techniques -proved Germ Theory of Disease thru Koch's Postulates (showing that 1 disease was caused by 1 microbe) -convincing proof that microbes associated w/ disease -K. Postulates: 1) isolate same microbe in all sick animal cases 2) grow the microbe in the lab 3) inoculate (inject) a healthy susceptible animal w/ the microbe so they get the disease & symptoms 4) isolate same original microbe from sick animal to prove theory Who was Ignatz Semmelweis (1800)? -delivered babies, discovered that Childbed Fever in laboring mothers could be prevented by hand-washing -in his ward, fatalities reduced from 10-1% -his idea was rejected, died in insane asylum, later recognized by Pasteur -"Pioneer of Antiseptic Procedures" -"Semmelweis Effect" is the tendency to reject new evidence or knowledge b/c it contradicts norms/beliefs Who was Joseph Lister? -used Phenol as antimicrobial, reduced infection -washed hands before surgery, heated equipment to sterilize -phenol is used as a basis for comparing other products - "Phenol Coefﬁcient" What is microbiology? -study of small life - microbes (aka viruses, bacteria, fungi, protozoa, algae) What are microbes? -no tissues, made of nucleic acid and/or proteins (some genetic material/DNA) -diseases, germs, bugs -microbes found in soil, air, water -there are 10 microbes found in/out of humans for every human cell -bacteria & archaea represent greatest mass of living cells on planet What are the microbial roles and what is the nitrogen cycle? -producers form organic nutrients thru photosynthesis (plants, algae, etc) -1st order consumers eat producers -2nd order consumers eat 1st order consumers -3rd order consumers eat 2nd order consumers -decomposers (fungi, bacteria, protozoa, archaea) break down dead organisms (all 3 consumers/producer) to recycle back into ecosystem -Nitrogen cycle: nitrogen in air used by bacteria in soil to change waste (urine/ feces from consumers) into nitrogen components for plants to use What are microbes used for? -producers: release oxygen and create/change nutrients -decomposers/recyclers: compost, sewage treatment, create food spoilage, can break down toxic waste -products: drugs (antibiotics), proteins, steroids, enzymes for cheese/yogurt, alcohol, toxins (botox) What are the features of a good microscope? -can magnify -provides deﬁnition -has resolving power (shows detail) +the shorter the wavelength, the better the resolution +improved by oil immersion (more light goes to lens) What are stains? -improve deﬁnition (b/w object & background) & structural/chemical information -done on smears: spreading bacteria out on slide w/ liquid (water/ink) What are smears? -w/ ink: negative stain, will stain background (air-dried, no cell shrinkage) -w/ water: positive stain, will stain cells (air-dried then heat ﬁxed to kill microbes, help them stick) What are simple stains? -one dye is used; chromophores in dye (+ charge) are attracted to microbe surface proteins (- charge), help dye stick to cell What are differential stains? -2+ dyes (primary stain & counterstain to distinguish cell types) -capsule stain: negative & simple positive stain combined What are the shapes/size of prokaryotic (bacteria/archaea) cells? -coccus (sphere) -bacillus (rod) -vibrios (curved rod) -spiral: spirillum (external ﬂagella) or spirochete (internal ﬂagella) -size: 1-10 micrometers What are the arrangements of prokaryotic cells? -coccus can be solitary (one), strep (chain), staph (cluster), tetrad (pack of 4), or packet (cube of 8) -bacillus can be solitary, strep, & palisade (zig-zag) -vibrios & spiral always solitary What is a glycocalyx? What are the two types? -only in prokaryotes; coating outside cell wall made of sugars/proteins 1) slime layer: loose matrix, thin slimy layer 2) capsule: densely packed, tightly bound to cell wall (resists staining too) What are the functions of a glycocalyx? -prevents cell from dehydration -source of nutrients -increases ability to stick to surfaces -inhibits killing by white blood cells thru phagocytosis -increases pathogenicity (cell's ability to cause disease) -considered a virulence factor (something on a microbe that increases ability to cause disease) -used by cells to make bioﬁlm What is bioﬁlm & how is it made? -consists of 30% microbes, cells expel DNA into it, has water channels for transporting nutrients & waste -difﬁcult for immune system & antibiotics to penetrate -cells that land on glycocalyx secrete extracellular matrix & DNA --> forms bioﬁlm -bacteria in bioﬁlm make inducer molecules that can communicate w/ other bacteria to know when QUORUM has been reached (a certain microbe density that means they can be effective together) -inducer molecules trigger genes in all cells on bioﬁlm to make a protein that enable them to cause damage What is the cell wall of bacteria? -determines shape of bacteria; prevents cell from breaking -made of peptidoglycan: sugar chains bonded w/ NAM & NAG (unique to bacteria, recognized by immune system of humans) What is the cell wall of Gram positive bacteria? -thick layer of peptidoglycan...underneath is periplasmic space, bottom is cell membrane -has techoic & lipotechoic acid for transport of ions What is the cell wall of Gram negative bacteria? -outer membrane of lipopolysaccharides (top) & phospholipids (bottom) +part of lipopolysaccharide is ENDOTOXIN (LIPID A) where cell wall should not be broken because it is highly toxic to human cells -after outer membrane is space, thin peptidoglycan, periplasmic space, then cell membrane -has porins in outer membrane (antibiotics too big to ﬁt thru, gives cell antibiotic resistance) What is the cell wall for archaea? -no peptidoglycan, instead made of protein & glycoprotein -outermost layer is S Layer (aka glycocalyx) What is the cell membrane for bacteria? -phospholipid bilayer + proteins (ﬂuid-mosaic, not stiff) -no sterols present -functions: selectively permeable, holds energy reactions, processess/ synthesizes nutrients, passageway for nutrients into/out of cell What is the cell membrane of archaea? -glycerol in phospholipid head is backwards, but otherwise same as for bacteria -have ether linkage in fatty acid tails to help resist heat What are ﬂagella for bacteria? -long thin tail: made of ﬁlament (spiral part, made of ﬂagellin protein), hook (curved sheath @ base), & basal body (stack of rings anchored to cell wall) How do bacteria w/ ﬂagella move? -using hydrogen pump, move towards nutrients -"run": ﬂagella move counterclockwise -"tumble": ﬂagella move clockwise What are the ﬂagella arrangements? -polar: ﬂagella @ one end -monotrichous: one ﬂagella @ one end -lophotrichous: tuft of ﬂagella @ one end -amphitrichous: ﬂagella @ both ends -peritrichous: ﬂagella all around perimeter What are ﬂagella for archaea? -ﬂagella moves using ATP, rest is similar What are ﬂagella for eukarya? -fall under category of undulipodia: cilia, ﬂagella (all hair-like structures in eukaryotic cells) -ﬁlaments made from tubulin, have ATPase to use/breakdown ATP for their movement -have centriole, not basal body, at the base of ﬂagella What are pilli? -only for Gram (-) bacteria -tube made of pilin protein -tubes connect cells together, used to share DNA back and forth (aka Conjugation) What are ﬁmbriae? -bristles that come off surface of G(+) & G(-) bacteria cells -function in helping cell adhere to other cells/surfaces -contributes to the virulence of a bacteria (more likely to cause disease) What is a eukaryotic cell's genome? -23 pairs of linear chromosomes, wrapped around histones -have a true nucleus What is a prokaryotic cell's genome? -nucleoid: region in cell where 1 chromosome circle is found (contains up to 4000 genes) -bacteria: no histones, archaea: histone-like structures -can have plasmid(s) What are plasmids? -extra chromosomal DNA, 1-20 per cell -do not carry genes required for life, but carry genes for antibiotic resistance, proteins to make virulence factors -can be transferred thru pilli to another bacteria -the larger the plasmid, the slower the replication of cell -plasmids unevenly distribute to daughter cells, is it a parasite? What are ribosomes? -found in all cells -site of protein synthesis; made of 60/40% RNA and protein -made of large & small subunits, coming together when synthesizing a protein -large subunit has ribozyme (RNA enzyme) called peptidyl transferase to hook amino acids together when making a protein -prokaryotes have 70S ribosomes, eukaryotes have 80S ribosomes What are endospores? -resting cells made by Gram (+) bacteria in the soil (mainly clostridium & bacillus) -become endospores when there is nutrient depletion (capable of long-term survival & are highly resistant) -germination = returning to vegetative growth -endospore is dehydrated due to dipicolinic acid & calcium, thus heat resistant -spore coat (made of keratin) gives resistance to acids, radiation, etc -immortal? resistant to cleaning methods & boiling...can be killed thru timed pressurized steam Facts about antibiotics/antimicrobials? -come from bacteria/fungi/molds -by producing antibiotics, bacteria lessen their competition for nutrients & space (kill off other microbes) -inducer molecules @ high concentrations can kill other microbes -antibiotics target bacteria, NOT viruses -antibiotics are selectively toxic: will attack something on a microbial cell that is NOT present in the host (human) cell +if the microbe & host cell have similarities, you may have side effects b/c selective toxicity may not be completely achievable What are narrow and broad spectrum antibiotics? -narrow: effective on small range of microbes (target one feature of a microbe) -broad: effective on large range of microbes What is the toxicity and therapeutic index? -toxicity: toxicity to host (want low)/toxicity to microbe (want high) (want low number once divided) -therapeutic: max dose tolerated by host/dose needed to kill microbe (want higher number once divided) What is penicillin? -1st antibiotic discovered -targets cell wall -narrow spectrum: affects Gram positive cells -contains beta-lactam ring (inactivated by beta-lactamase, which is produced by bacteria; can become penicillin-resistant) -disadvantage: people may be allergic What do all the "illins" have in common? -contain beta-lactam ring (inactivated by beta-lactamase, which is produced by bacteria; can become penicillin-resistant) What is ampicillin? -targets cell wall -broad spectrum: affects Gram positive & negative cells -disadvantage: people may be allergic What is methicillin? -targets cell wall -narrow spectrum: affects Gram positive cells -disadvantage: quickly became ineffective due to resistance in bacteria - 50% staph. infections are caused by MRSA (methicillin-resistant Staph. A) What is cephalosporin? -used when person is allergic to penicillin -targets cell wall -broad spectrum: affects Gram positive & negative cells -contains beta-lactam ring too -disadvantage: hard to absorb (need shots) What is vancomycin? -targets cell wall -narrow spectrum: affects Gram positive cells (staph, strep) -used for MRSA (if someone is penicillin & methicillin resistant) -disadvantage: can be toxic, hard to absorb (need IV) -bacteria also becoming vancomycin-resistant, used as last resort (VRE, VRSA) What is bacitracin? -targets cell wall -narrow spectrum: affects Gram positive cells -disadvantage: toxic to kidney, external use only (used topically as ointment) What is lysozyme? -enzyme found in our own body ﬂuids -targets cell wall -narrow spectrum: affects Gram positive cells What is polymyxin? -targets cell membrane (acts as detergent to dissolve lipids) -narrow spectrum: affects Gram negative cells -disadvantage: not selective - we also have cell membranes! Used topically only What is amphotericin B? -targets cell membrane -narrow spectrum: affects fungi (athlete's foot, jock itch) -disadvantage: semi-selective, allergies, toxic if taken internally How do alcohols, soaps and detergents work on bacteria? -dissolve lipids and break apart plasma membrane How does anything that denatures proteins work on bacteria? -attack cell membrane, speciﬁcally denature proteins -break hydrogen & disulﬁde bonds -things that do this: acids (using hydrolysis), chlorine/bleach/iodine (using oxidation) What did Alexander Fleming discover? -discovered penicillin within penicillium mold in 1900s, effective against Staph. A. -later puriﬁed/produced by Howard Florey & Ernst Chain a decade later What is tetracycline? -targets 70S & 80S type ribosomes -broad spectrum: affects prokaryotic/eukaryotic microbes -disadvantage: not for kids (slows growth, discolors teeth), liver damage What is erythromycin? -targets 70S ribosomes -narrow spectrum: affects Gram positive bacteria -toxicity: upsets stomach What is chloramphenicol? -targets 70S ribosomes -broad spectrum: affects Gram positive & negative -disadvantage: aplastic anemia (damage to bone marrow, prevents production of RBC's) What are aminoglycosides? -aka streptomycin -targets 70S ribosomes -broad spectrum: affects Gram positive & negative -disadvantage: deafness, kidney damage What is taxonomy? -science of naming/classifying organisms What did Carollus Linnaeus & Carl Woese do? -established classiﬁcation -genus & species create the scientiﬁc name of an organism -classiﬁed bacteria & archaea according to differences in rRNA What are the cell types, 3 domains, and 6 kingdoms? -prokaryotic & eukaryotic -bacteria, archaea, eukarya -bacteria, archaea, animalia, plantae, fungi, protista How do we classify prokarya? 1) morphology: shape, arrangement, ﬂagella under microscope 2) macroscopy morphology: colony appearance (color, texture) 3) bacterial physiology: metabolism, how they make ATP, temperature preference, nutrient requirements 4) serological analysis: expose to antibodies to see if our body recognizes it 5) genetic/molecular analysis: ribosomal RNA analysis, protein analysis What is the domain archaea? -most common, widespread organism: have their own domain & kingdom -more related to eukaryotes (humans) than bacteria -no peptidoglycan (have S layer), ribosomes similar to eukaryotes, histone-like molecules -have unique DNA polymerase -can live in extreme environments -methanogens: methane lovers -halophiles: salt lovers -hyperthermophiles: heat lovers -thermoacidophiles: acid lovers What is the domain bacteria? -G(+): ﬁrmicutes (stain purple), make endospores & acid-fast (think "ﬁrm" for thick layer of peptidoglycan) -G(-): gracilicutes (stain pink) -tenericutes: NO cell wall What is a vector, reservoir, transmission, and polymorphism? -vector: something living that can transfer the microbe from one host to the next -reservoir: a source of the microbe in nature -transmission: how the microbe enters the host -polymorphism: existing in multiple forms of life What are spirochetes? -a type of gracilicute -has ﬂexible endoﬂagella made of ﬂagellin -they are G(-) human pathogens -their endoﬂagella help them hide from white blood cells -diseases caused by them: Lyme disease, Syphilis What is Lyme Disease? -disease caused by spirochete -emerged in Lyme, Connecticut -index cases: group of kids w/ arthritis led to the discovery of the microbe -vector: ticks -reservoir: a mouse -transmission: innoculation (skin broken, microbe enters) -not communicable (not transferrable to others), but can enter placenta to an unborn baby -symptoms: 1) primary: shows bulls-eye rash, ﬂu-like symptoms 2) secondary: if untreated, cardiac & neurological issues 3) tertiary: arthritis-like symptoms -treatment: antibiotics What is Syphilis? -disease caused by spirochete -vector & reservoir: humans (cannot survive outside of host) -transmission: direct contact (sex) & can enter placenta -symptoms: 1) primary: chancre where spirochete binds; highly contagious, chancre disappears b/c spirochete enters bloodstream 2) secondary: spirochete enters bloodstream, rash all over skin, ﬂu-like symptoms, rash eventually disappears 3) tertiary: gummas (swollen tumors), cardiovascular damage -treatment: penicillin What is Rickettsia? -a type of gracilicute; are a small obligate intracellular parasite (cannot survive outside of host cell) -non-motile, shaped like coccobacillus (oval) -vector: tick -bacteria would enter thru endothelial cells (lining of blood vessels), cell lyses, hemorrhaging occurs & circulatory collapse along w/ blockage of blood ﬂow -diseases caused by rickettsia: Rocky Mountain Spotted Fever, Typhus What is Rocky Mountain Spotted Fever? -disease caused by rickettsia -vector & reservoir: tick, usually bites rodents (if mother tick carries microbe, all her babies carry microbe) -symptoms: rash on wrists/ankles that spreads, shock, central n.s. damage, coma (untreated = 20% mortality rate) -treatment: antibiotic What is Typhus? -disease caused by rickettsia -spreads easily during natural disasters when people have to live in small intimate settings -vector: body lice -reservoir: humans -transmission: lice feces being rubbed into a bite, or inhaling of dried feces -symptoms: ﬂu-like, rash, coma (60% mortality) -treatment: antibiotics What is Chlamydia? -a type of gracilicute; obligate intracellular parasite -exhibits polymorphism: exists in multiple forms of life 1) elementary body: metabolically inactive form, can live outside of cell when released from host cell 2) reticular body: non-infectious, growing/dividing w/in the host cell they infect -transmission: direct contact (sex) -chlamydia trachomatis: infection of mucous membrane of eyes, genitals, lungs *ex: occular trachoma: deformed eyelid & cornea, large cause of blindness *ex: conjunctivitis: occurs as baby passes thru birth canal -chlamydia as STD: second most prevalent STD; inﬂammation of urethra, cervix...can cause infertility/scarring What is Cyanobacteria? -a type of gracilicute living in water, uses photosynthesis to produce oxygen -can grow in colonies AKA blooms -evolved ~3 billion years ago, played role in changing Earth's atmosphere to one w/ oxygen -when atmosphere started changing to more oxygen, almost all anaerobes went extinct What are tenericutes? -bacteria w/out a cell wall, only a cell membrane -have no speciﬁc shape due to lack of cell wall (fried-egg appearance) -have sterols in membrane for ﬂexibility (the only bacteria to do this) -surface adhesins allow them to bind to cells (hard to dislodge) -non-motile, facultative anaerobes (can live w/ & w/out air) -will Gram stain pink (for negative) -includes genus of mycoplasma What are mycoplasma? -no cell wall, only cell membrane -pleomorphic: all sorts of shapes -cause infections on mucous membranes *ex: mycoplasma pneumoniae: spreads over respiratory surfaces, causing fever, chest pain, sore throat *ex: mycoplasma genitalium: sexually transmitted pathogen Table facts about Bacteria? -cell type: prokaryotic -has a glycocalyx -has a cell wall; made of peptidoglycan -has an outer membrane (ONLY G(-)) -has a cell membrane (no sterols) -has a genome; w/ nucleoid, single circular chromosome, and plasmid (extra chromosomal DNA) -ribosome type 70S -has ﬂagella -has pili (ONLY G(-)) -has ﬁmbriae (BOTH G(+) & G(-)) Table facts about Archaea? -cell type: prokaryotic -has glycocalyx -has a cell wall; made of protein (S layer) -has a cell membrane; no sterols, backwards glycerol, ether linkage -has a genome; w/ nucleoid, single circular chromosome, plasmid (extra chromosomal DNA), & histone-like molecules -ribosome type 70S -has ﬂagella Table facts about Eukarya? -cell type: eukaryotic -has glycocalyx (ONLY fungi & plants) -has a cell wall; made of cellulose & chitin (ONLY plants) -has a cell membrane; w/ sterols -has a genome; w/ nucleus, linear chromosomes, & histones -ONLY yeast have plasmids (extra chromosomal DNA) -ribosome type 80S -has undulipodia
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