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Download MICR 3050 EXAM 2 CLEMSON EXAM QUESTIONS WITH REVISED CORRECT ANSWERS A+ VERIFIED LATEST and more Exams Advanced Education in PDF only on Docsity!
MICR 3050 EXAM 2 CLEMSON EXAM QUESTIONS WITH REVISED CORRECT ANSWERS A+ VERIFIED LATEST VERSION Bacterial Capsule (description) - correct answers-usually consist of polysaccharides (sometimes protein) Well organized around cell Not easily removed Virulent/pathogenic factor Must perform negative stain to see Bacterial capsule advantages - correct answers-allow or attachment to surfaces can group together to form biofilm protect against desiccation (drying) protect against phagocytosis protect against bleach/toxins/virus nutrient absorption Slime layers - correct answers-similar to capsules except diffuse, unorganized and easily removed mucous-looking aid in motility Cell inclusions - correct answers-aggregate of organic/inorganic material enclosed by a "membrane" that appear as masses under a microscope Storage inclusions - correct answers-nutrients in high concentration in environment are absorbed and stored for use when concentration becomes low Poly-B-hydroxybutyrate (PHB) - correct answers-carbon energy inclusion in bacteria Phosphate granules - correct answers-phosphate energy inclusion in bacteria Sulfur globules - correct answers-Sulfur energy inclusion in bacteria Needed for CO2 fixation IN PERIPLASM, NOT CYTOPLASM Non-storage inclusions - correct answers-granules of enzymes, structures, or specific chemicals that are required for proper cell function Types: carbonate minerals, magnetosomes, gas vesicles Carbonate minerals - correct answers-non-storage inclusion that serves similarly to a ballast of a ship- resist lateral forces magnetosomes - correct answers-non-storage inclusion that stores magnetite- use magnetism to move DOWN in water to a LOW O2 ENVIRONMENT gas vesicles - correct answers-non-storage inclusion that allows bacteria to float made of protein impermeable to water, but permeable to gas seen in photosynthetic bacteria Bacterial endospores - correct answers-complex dormant survival structures discovered by Cohn due to their heat resistance stay in dormant state until conditions are preferable Determine heat @ which we sterilize Sporangia - correct answers-endospore-producing bacteria Species that produce endospores - correct answers-Bacillus and Clostridium Endospore Resistance - correct answers-heat/freezing, starvation, chemicals, desiccation, radiation SASPs - correct answers-small acid soluble proteins- bind DNA to compact and protect it Sporulation - correct answers-endospore formation Sporulation steps - correct answers-1) commitment to sporulation when cell begins asymmetric division 2) cell wall grows and creates a partition, called the septum, between the prespore and rest of cell 3) Engulfment- mother cell cytoplasm goes around prespore which becomes a spore w/ outer membrane 4) cortex forms between spore cell wall and membrane 5) spore coat put on, calcium enters to dehydrate, SASPs enter 6&7) maturation and lysis germination - correct answers-endospore returns to vegetative state Formation of Vegetative Cell - correct answers-activation, germination, outgrowth activation (veg. cell) - correct answers-endospore prepares for germination usually comes from heat treatment can be reversed so that the endospore doesn't enter germination germination (veg. cell) - correct answers-good environment detected- takes time because nutrients must pass through dense layers begins to let in water and swell- this erupts the outer layers metabolic activity increases but resistance is lost outgrowth (veg cell) - correct answers-emergence of vegetative cell External cell structures - correct answers--flagella -fimbriae -pili protection, surface attachment, gene transfer, motility Fimbriae and pili - correct answers-short, think hair-like projections made of proteins about 1000/cell mediate surface attchement and some (type IV pili) used for motility or DNA uptake (transformation) Sex pili - correct answers-similar to fimbriae except longer, thicker, and less numerous DNA FOR FORMATION FOUND ON PLASMIDS required for CONJUGATION 1-10/cell Types of cells with external structures - correct answers-ALL gram negative have, some gram positive Flagella functions - correct answers-motility and swarming attachment burrowing into tissue virulence factor- help bacteria be better pathogens Types of bacteria w flagella - correct answers-All spiroles half of bacilli few cocci Monotrichous flagella - correct answers-one flagella polar flagella - correct answers-flagella only at the end of a cell Amphitrichous flagella - correct answers-one flagellum at each end Flagella biosynthesis - correct answers-MS/C ring assembly motor proteins insert P ring Lring early hook late hook cap hook filament synthesis Direction of flagella growth - correct answers-TOP DOWN filaments are added to the cap, not the hook-filament junction Gram positive flagella - correct answers-only composed of 2 motor rings because their thick peptidoglycan layer provides a lot of support forward flagella motion - correct answers-counterclockwise Tumble flagella direction - correct answers-clockwise Spirochete motility - correct answers-have endoflagella- flagella inside the cell that allows flexing and spinning movement can burrow into tissue axial fibrils - correct answers-Flagella of some spirochaetes, which are anchored to the bacterium at either end and wrapped around the peptidoglycan layer. These flagella move the bacterium with its characteristic corkscrew motion, but the exact mechanism used is not fully understood. adventurous motility - correct answers-secret a polysaccharide slime to slide across surface Social motility - correct answers-swarming behavior in colonies -pili assemble ahead of cell and pull -conveyor- rotate cell like a corkscrew Glide proteins - correct answers-proteins on outer membrane that walk like feet Chemotaxis - correct answers-Cell movement that occurs in response to chemical stimulus Complex but RAPID response chemoattractants - correct answers-compounds that, when detected by bacteria, attract movement chemorepellents - correct answers-compounds that repel particular classes bacteria when detected Chemoreceptors - correct answers-on surface of cell that detect environment Chemotrophs - correct answers-digest organic/inorganic chemicals for energy phototrophs - correct answers-obtain energy from light organotrophs - correct answers-obtain electrons from organic compounds lithotrophs - correct answers-use inorganic molecules as a source of electrons heterotrophs - correct answers-use organic molecules as a carbon source autotrophs - correct answers-use CO2 as carbon source photolithoautotroph - correct answers-Carbon Source: CO2 Energy Source: Light Electron Source: Inorganic e- donor plants, cyanobacteria, photosynthetics Standard reduction potential (E) - correct answers-measurement of a reducing agents tendency to lose e neg E = better DONOR pos E = better ACCEPTOR relationship between E and delta G - correct answers-the greater the difference between the E of donor and acceptor means the delta will be more negative (spontaneous/exergonic) coenzymes - correct answers-electron carries that can freely transfer e- from one area of a cell to another (like NADH) prosthetic groups - correct answers-electron carriers fixed in the plasma membrane like cytochromes in EIC NAD+ - correct answers-can carry 2 e- and 1 H+ NAD+ involved in catabolism NADH involved in anabolism substrate-level phosphorylation - correct answers-ATP is synthesized when an organic compound breaks down substrate carries a P to give to ADP seen in fermentation oxidative phosphorylation - correct answers-ATP synthesized by a proton motive force used in aerobic and anaerobic respiration photophosphorylation - correct answers-light drives a redox reaction that generates a proton motive force used in phototrophic organisms Glycolysis - correct answers-2 net ATP 2 NADH glucose -> 2 pyruvate Fermentation - correct answers-used when electron acceptor is absent continuously recycles e- carriers ex: NADH from glycolysis is oxidized to NAD+ to be reused in glycolysis again Fermentation classes - correct answers-Classify bacteria based on end fermentation product: Ethanol, Lactic acid, Mixed acid, 2,3-butanediol, Propionic acid Lactic acid ferments (2 types) - correct answers-homolactic- sole product is lactic acid (some cheeses, sour cream, yogurt) heterolactic- produces ethanol and CO2 as well (sauerkraut, pickles, buttermilk) propionic acid fermentation - correct answers-makes swiss cheese ethanol fermentation - correct answers-makes wine bread and beer Voges-Proskauer Test - correct answers-detects acetoin, an intermediate in the production of butanediol Main phosphorylation in respiration - correct answers-oxidative phos Location of ETC in Eukaryotes vs Bacteria and Archaeons - correct answers-Eukaryotes- inner mitochondrial membrane Bacteria & archs- cytoplasmic membrane (because this is a double membrane, too) ATP per NADH and FADH2 - correct answers-3 ATP per NADH 2 ATP per FADH2 2 NADH (x 3= 6ATP ox. phos) Krebs: 6 NADH (x 3= 18 ATP ox phos) . 2 FADH (x 2= 4 ATP ox phos) 2 ATP (sub level phos) ATP totals aerobic respiration - correct answers-4 via SLP 34 via oxidative phosphorylation anaerobic respiration - correct answers-non-oxygen final acceptor yields less energy because of this- falls down e- tower less growth - correct answers-refers to increase in # of cells we study population growth, not individual Binary Fission - correct answers-2 cells rise from one (this is considered one generation) are genetically identical Binary fission steps - correct answers-1) cell elongates- DNA is duplicated, cell mem/wall lengthens, organelles double 2) septum forms- cell wall and mem pinch in when chromosomes separate 3) Septum forms completely- separates cells as a patch between 2 chambers 4) division- 2 new daughter cells identical 4 microbial growth phases - correct answers-lag, exponential, stationary, death seen in growth in a batch- have limited nutrients Lag phase - correct answers-cells have to adapt to new environment conditions begin synthesizing new components can be very long to very short in time Exponential phase - correct answers-CONSTANT and MAXIMAL RATE of growth population is most uniform in terms of chemical and physical properties This is where the healthiest cells are and where its best to study cells Stationary phase - correct answers-TOTAL number of cells is CONSTANT this could be due to: - metabolically active cells stop reproducing - reproduction and death rates are balanced something will always limit growth like: nutrients, oxygen, toxic waste accumulation, or critical population density Starvation responses - correct answers-Morphological changes production of starvation proteins persister cells morphological starvation responses - correct answers-endospore formation reduction in size starvation protein response - correct answers-produce certain enzymes and proteins that increase cell- wall cross linking Dps protein are produced that protect DNA in starving cells Persister cells - correct answers-use starvation proteins and become stronger become virulent, absorb more food, resistance change some persisters can survive for years- salmonella is caused by persisters and are hard to kill Death Phase - correct answers-total viable cells is decreasing Membrane filter - correct answers-(direct) used for dilute samples like water pass large volumes through filter then put filter on plate Turbidity - correct answers-(indirect) choose light filter that will be maximally absorbed by bacteria measures amount of light transmitted (more cells=less transmitted=more absorbed) have to relate this value to a direct cell count on a standard curve Cardinal growth temperatures - correct answers-minimal- cell can't go through binary fission and membrane gels optimum- enzymes work @ fastest possible rates maximum- protein denaturation, collapse of membrane OPTIMUM IS ALWAYS CLOSER TO MAX THAN TO MIN Temperature classes (coldest to hottest) - correct answers-psychrophiles (REALLY cold) psychrotolerant (cold) mesophiles (normal temp) thermophiles (hot) hyperthermophiles (hot as balls- usually have a lipid monolayer) Bacteria in cold environments - correct answers-have high unsaturated fatty acid content in bilayer to increase flexibility Bacteria in hot environments - correct answers-enzymes have a lot of interaction in quat/tertiary structure to keep stable high saturated fatty acid content in plasma membrane taq polymerase - correct answers-DNA polymerase in thermal microbes used in PCR to denature DNA at higher temperatures tolerable pH - correct answers-most bacteria live in 3-9 can tolerate changes by about 2 pH Responses to pH change - correct answers-produce buffer to bring surroundings to more neutral pH use sodium motor force acid shock proteins acid shock proteins - correct answers-protein that is released when pH changes to stop acid denaturation of proteins and hold the proteins together so that H+ can't unfold them Can also RENATURE some enzymes Water activity (aw) - correct answers-amount of water available to organism 1= pure water, 0= no water higher solute = lower aw Hypotonic solution adaptations - correct answers-mechanosensitive channels (MS)- membrane channel that allows solutes to leave so less water enters hypertonic solution adaptations - correct answers-increase solute concentration in cell stockpile COMPATIBLE SOLUTES- these are unused ions and solutes stored for this purpose NaCl tolerance (least saline to most) - correct answers-nonhalophile- die in salt like E. coli halotolerant- tolerate salt, don't need it halophile- require 1-15% salt to grow extreme halophiles- require 15-30% salt to grow obligate aerobe - correct answers-require oxygen for growth aerobic respirators ecology - correct answers-study of relationship between organisms and environment population - correct answers-group of organisms of SAME SPECIES in same place and time guild - correct answers-metabolically related microbial populations (all aerobic/anaerobic/fermenter) Community - correct answers-2 or more cell populations coexisting in same area ecosystem - correct answers-sum of all organisms and abiotic factors (lakes, ocean, forect, etc) habitat - correct answers-portion of ecosystem where community could reside niche - correct answers-habitat shared by a guild there are "prime" or "realized" niches where an organism is most successful alpha diversity - correct answers-diversity within a community total number of species and proportion beta diversity - correct answers-comparison of samples (between community diversity) gamma diversity - correct answers-Total species diversity across all communities (regional scale) nitrification - correct answers-NH4+ to NO3 ammonia to nitrate denitrification - correct answers-NO3 to N2 nitrate to nitrogen gas nitrogen fixation - correct answers-N2 + 8H to NH3 + H2 nitrogen gas to ammonia ammonification - correct answers-N to NH4+ organic nitrogen decomposition to ammonia anammox - correct answers-NO2- + NH3 to N2 anaerobic ammonia to nitrogen gas nitrogen fixing bacteria - correct answers-aerobic: cyanobacteria anaerobic: purple and green phototrophs Nitrification bacteria - correct answers-Nitrasomonas and Nitrobacter NH4+ to NO2 to NO3 Rhizobia - correct answers-soil bacteria that fix nitrogen after becoming established inside root nodules of legumes 25% of nitrogen fixing on Earth is due to these nodules Ruminants - correct answers-herbivorous mammals that possess a rumen Rumen - correct answers-digestive organ where cellulose and other plant polysaccharides are digested by microbes abomasum - correct answers-true stomach of ruminants Food path in ruminants - correct answers-1) enters esophagus and passes to reticulum- sorts and filters food 2) small particles go to omasum and abomasum 3) large particles go to rumen where microbes breakdown 
