BIOL3003 - EXAM 2 CONTENT EXAM QUESTIONS AND
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
Biofilms
Microbial communities; attached to surface covered with a protective matrix.
Four steps of biofilm formation
attachment, colonization, maturation, dispersal
Attachment
- preconditioning: microbes lay down polysaccharides, other sugars, proteins.
- Pili can mediate attachment
- adherence to proteins
Colonization
- Quorum sensing: cell-to-cell signaling that is density dependent.
- activated genes to make matrix of polysaccharide, protein, and DNA
Maturation
- Mushroom with channels for nutrients and oxygen gradients (aerobic/anaerobic)
Metabolic process of tooth decay
Bacterial fermentation --> acidic products --> enamel
Bacteria that causes the development of dental plaque (biofilm) on tooth surfaces
Streptococcus mutans
Bacteria that causes periodontal disease
Porphyromonas gingivalis
, Environmental factors that influence microbial growth
Oxygen concentration, temperature, solutes and water activity
Microbes that grow in extreme environments
extremophiles
Obligate aerobe
Requires oxygen
Facultative anaerobe
Can grow without oxygen but prefers it's presence
Aerotolerant anaerobe
Ignores the presence of oxygen
Obligate anaerobe
Oxygen is toxic for microbe (grows where less/no O2 is present)
Microaerophile
grows in very specific O2 amounts (2-10%)
Oxygen can be reduced to toxic products called
reactive oxygen species
Hyperthermophiles
grow between 85-113 degrees C
Thermophiles
grow between 45-85 degrees C
Example of a thermophile and source of Taq polymerase
Thermus aquaticus
Normally, high temperature...
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
Biofilms
Microbial communities; attached to surface covered with a protective matrix.
Four steps of biofilm formation
attachment, colonization, maturation, dispersal
Attachment
- preconditioning: microbes lay down polysaccharides, other sugars, proteins.
- Pili can mediate attachment
- adherence to proteins
Colonization
- Quorum sensing: cell-to-cell signaling that is density dependent.
- activated genes to make matrix of polysaccharide, protein, and DNA
Maturation
- Mushroom with channels for nutrients and oxygen gradients (aerobic/anaerobic)
Metabolic process of tooth decay
Bacterial fermentation --> acidic products --> enamel
Bacteria that causes the development of dental plaque (biofilm) on tooth surfaces
Streptococcus mutans
Bacteria that causes periodontal disease
Porphyromonas gingivalis
, Environmental factors that influence microbial growth
Oxygen concentration, temperature, solutes and water activity
Microbes that grow in extreme environments
extremophiles
Obligate aerobe
Requires oxygen
Facultative anaerobe
Can grow without oxygen but prefers it's presence
Aerotolerant anaerobe
Ignores the presence of oxygen
Obligate anaerobe
Oxygen is toxic for microbe (grows where less/no O2 is present)
Microaerophile
grows in very specific O2 amounts (2-10%)
Oxygen can be reduced to toxic products called
reactive oxygen species
Hyperthermophiles
grow between 85-113 degrees C
Thermophiles
grow between 45-85 degrees C
Example of a thermophile and source of Taq polymerase
Thermus aquaticus
Normally, high temperature...
