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WorksheetsExtreme Environment and Biofilm - MicroCore Review Center
Total questions: 10
Worksheet time: 5mins
Which is not one the three general mechanisms of adaptations of extremophiles?
Adaptation
Exclusion
Detoxification
Reconstruction
Which of the following is not an adaptation of microorganisms in low temperature environment?
branched chain fatty acids
short chain fatty acids
trans-unsaturated fatty acids
polar carotenoids
Which of the following is not true about the adaptations of microorganisms in extreme pH?
Cell walls of alkaliphiles have cell wall that contains acidic polymers
One adaptation of acidophiles is that the cell membrane is highly impermeable to protons
Membrane channels of acidophiles have reduced pore size
Alkaliphiles have a slightly higher internal pH
Proton uncoupling by organic acids is one of the adaptations by alkaliphiles
Which of the following is not true about the adaptations of extremophiles in high saline environments?
High amount of aromatic amino acid residues
Involves accumulation of molar concentrations of potassium through the K+ symport mechanism
Cytoplasmic proteins must be adapted to an ionic cytoplasm
High amounts of acidic amino acids over basic residues
What is an environment with a neutral to slight alkaline pH and a dominance of sodium (about 20%) and chloride ions?
Solfatara
Thalassohaline
Coal Refuse Pile
Athalassohaline
Which of the following is true about biofilms?
Typically composed of a single species of microorganism
Encased microcolonies of bacterial cells detached from a surface of polysaccharides
Unlike the planktonic lifestyle, biofilms cannot offer protection for bacteria against environmental, chemical, and mechanical stresses.
Aggregation of microorganisms marked by the excretion of a protective and adhesive matrix
What is the proper sequence of biofilm formation?
Adhesion of pioneer bacteria, surface conditioning, slime formation, secondary colonizers, fully functioning biofilm
Adhesion of pioneer bacteria, surface conditioning, slime formation, secondary colonizers, fully functioning biofilm
Surface conditioning, adhesion of pioneer bacteria, slime formation, secondary colonizers, fully functioning biofilm
Surface conditioning, slime formation, adhesion of pioneer bacteria, secondary colonizers, fully functioning biofilm
Which of the following is not true about how biofilms are spread?
Detachment is any mechanism which causes individual cells or cell masses to separate from the substratum to which the biofilm is attached
Rapidly growing biofilms exhibit slower rate of detachment that fast growing ones.
Seeding dispersal is a phenomenon which begins as the interior of a biofilm micro-colonies liquefies and ends as the outer layer of the colony is breached permitting the escape of plantonic cells
In rippling, the mass of biofilm appears to move in waves propelled at as much as 1 mm/hour by the force of the flowing water
Detachment is usually associated with dispersal and dispersal is typically a concomitant event with detachment
Which of the following is not true regarding how bacteria find and attach to surfaces and how biofilms are formed?
Bacteria form biofilms for food.
Bacteria form biofilms for protection since these serve as protective shields.
After adaptation to biofilm mode of life, microorganisms are found to be more hydrophilic as compared to planktonic or wild-type isolates and cell surface hydrophilicity increased with incubation time
Diffusion limitations imparted by the biofilm structure result in local variations in nutrient availability, pH, and oxygen tension.
Which of the following factors affecting attachment and growth of biofilms are considered under substratum effects?
Conditioning films
Hydrodynamic effects
Ionic strength
Flow velocity
Microbial interactions
