Chapter 9: Microbial Growth Flashcards
The process of diluting sample several times to prevent overgrowth on plates
Serial dilution
Microbial community that usually forms as slimy layer on surface
Biofilm
The three different ways that prokaryotes reproduce?
Budding, binary fission, fragmentation
The different phases of bacteria growth and what happens during those phases /
Lag Phase: No growth during this time interval in bacterial growth curve
Log Phase: Bacterial growth or logarithmic increase in cell numbers
Stationary Phase: Number of cells dividing equal number dying in bacterial growth curve
Death Phase: Decrease in bacterial population
Direct methods to measure growth and how they measure growth
Plate counts: counting CFUs on solid culture medium
Filtration: Bacteria is filtered out of culture onto membrane; membrane transferred to media
Most Probable Number (MPN): statistical determination of numbers of coliforms per 100ml of water or 100g of food
Direct Microscopic count: enumeration of cells by observation through microscope
Indirect methods to measure growth and how they measure growth
Turbidity: cloudiness or suspension, measured using spectrophotometer
Metabolic activity: Assumes certain metabolic products are in proportion with population growth
Dry weight: Fungus removed from media; filtered and dried in desicator, then weighed
Group of cells large enough to be seen without microscope
Colony
Organisms that CAN grow WITH oxygen
Obligate aerobes
Organism that CAN grow WITH/OUT oxygen
Facultative anaerobes
Organism that DOES NOT USE / KILLED by oxygen
Obligate anaerobes
Organism that DOESN’T use oxygen BUT is not affected by its presence
Areotolerant anaerobes
Organism that grows BEST in environment with LESS Oxygen than is normally found in air
Microaerophiles
Grow in acidic environments
Acidophiles
Grow in basic environments
Alkaliphiles
Cold loving
Psychrophiles
