MICRB 265 Midterm 2 Questions/answers

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University of Alberta
Microbiology (Biological Sciences)
Lisa Stein

TF prototroph and auxotroph are only used in MICRB 265 Midterm 2 QA reference to organic nutrients ie growth factors TMicrobial Nutrition and GrowthMatch the culture medium with the definition What are the building block macronutrients CHONPSA Defined Distinguish based on Match the macronutrient with the use biochemical reactionsB Complex Contain ingredients of A K Na Enzymatic functions eg unknown composition and DNA pol enable growth of B Ca Mg Cytochromes and xsulfur fastidious heterotrophs proteins Eg BAP or Brainheart infusions C Mg Cell wall polymers spores C Selective All components and dipicolonic acid concentrations are known D Fe Membrane transport D Differential Favours some inhibits C D B A othersWhich element is part of SOD D B A CMn Define growth in the context of bacterial growth curves Generally what can Mn Zn Co Mo Ni and Cu be used an increase in cell number over time for Cofactors of enzymes Which takes longer replication of bacterialchromosome or cell division Which nutrient is commonly limiting in microbesReplication of the chromosome is more time 2 Fe consuming so multiple rounds are initiated at the sametime 32 are used for AAs nucleicand POTF NH SO 434acids and enzymes vitamins and AAs and nucleic How do prok cells reproduce acids and lipids respectivelyBinary fission 2and HPO F NH 44 What is a divisome 3 Siderophores chelate Feand may be attached to theA divisome is the Fts and other proteins needed for binary fission cell wall or excreted into the medium Which organismsmake siderophores and why What is the phenotype of strains unable to create FtsFungi and bacteria make siderophores in ironproteins deficient mediumThese strains are filamentous temperaturesensitive What are enterobactin and aquachelinEnterobactin is made by E coli in pathogenesis Describe how the MinE and FtsZ proteins work together to get enough iron and aquachelin binds lipidsoluble during fission micelles for transport directly through the cytoplasmicMinE oscillates from side to side to find the membranemidpoint of the cell while FtsZ creates a ring around theexact midpoint through ATP hydrolysis Which is less soluble and more common in the 23 environment Fe or Fe 3What are autolysins similar to What is their functionFeAutolysins are similar to lysozyme and they cutinto the cell wall to make more membrane and wall Define growth factor parts in dividing cells organic nutrients such as AAs vitamins andNAs composed of macronutrients and trace elements nTF penicillin is most active during this process NN2 o T penicillin can interfere with transpeptidation n33 log Nlog N onow n tg What is the function of bactoprenol When are survival and maintenance genes inducedBacto prenol is a cytoplasmic protein that Give an example carries peptidoglycan precursors across the membraneDuring stationary phase for example Bacillus to creat new cell wall during septation and separation will form an endospore from vegetative cells after the protein ring has pinched to create two newdaughters Why is the idea that stationary phase due to crowdingor lack of resources irrelevant to microorganisms Does the growth curve represent a batch culture or a 1 Substrates are not limited in rich media chemostat 2 Bacterial colonies on plates are already highThe curve represents a batch culture but not a density when they are growing in general chemostat natural or continuous cultureWhen might starvation be a factor Generation times are functions ofand On minimal mediumMicroorganism environment What two factors may contribute to stationary phaseenzyme synthesis occurs during the lag phaseOxygen deprivation and product inhibition egDe novo toxic waste buildup TF it is possible to put cells on batch culture without a What is a livedead stain How would a VBNC cell stain lag phaseA livedead stain uses differences in cell wallT when the cells are initially in exponential structure between living and dead cells to differentiate phase and the new culture is identical in composition living ones from dead ones Green cells are living and and environmental conditions red cells are dead VBNC cells will be green because they are Circle the conditions that affect how rapidly a cell enters technically alive but in a dormant stage where they are exponential growth phase unable to grow and divide Name some methods for measuring microbial growth 1 Growth substratesMethods include direct count very accurate 2 Nutritional mode of organism stained bacteria etched slides good for yeasts and 3 Gram pos or Gram neg eukaryotes viable cell counts and plating diluted 4 Environmental factors samples only counts cells that are reproductively 5 Age of culture active giving results in CFUs turbidimetric mostcommon and easiest 6 Growth substrates7 Nutritional mode of organism Define Great Plate Count Anomaly 8 Gram pos or Gram negthe incredible disparity between direct 9 Environmental factors microscopic counts in an environmental sample with 10 Age of culture what we can culture in the lab May be due to Older cultures tend to exhibit atendency 1 Bacteria are mostly dead least likelyVBNC 2 Syntrophy3 VBNC some will be TF the younger the culture the longer the lag phase 4 Bacteria are culturable but we dont know whatF older they eat most likelyTF cultures transferred to rich media from poorer Cells in a chemostat are always inphase media will always exhibit lag phase but not necessarilyExponential the reverse T
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