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Chapter 5
Microbial Growth and Nutrition
57
Microbiology
Undergraduate 1
09/26/2014

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Term
Asexual Reproduction
Definition
Process to maintain genetic constancy while increasing cell numbers
Term
Binary Fission
Definition
A mechanism Majority of bacteria reproduce. Is much simpler than the mechanism of cell division seen in eucaryotic cells.
Term
Generation Time
Definition
Time it takes for a population of bacteria to double in number.
Term
Short Generation Time
Definition
20-60 minutes under optimum conditions
Term
Long Generation Time
Definition
Most common pathogens in the body time is closer to 5-10 hours.
Term
Tetrad
Definition
Complete separation of cells during Binary fission doesnt occur, occurs in 2 planes, and creates a center square with four cocci, one located at each conner
Term
Sarcinae
Definition
Complete separation of cells during Binary fission doesn't occur, occurs in 3 planes, and creates a center square with 8 with one coccus at each corner.
Term
Lag Phase
Definition
Transfer of bacteria from one medium to another. Bacteria is becoming accustomed to new environment.
Term
Log Phase
Definition
Binary Fission Occurs. Bacteria growth in numbers, not in size. Generation time is included at this time. Continues culture can also be conducted to keep bacteria growing. Exponential growth can be 20 minutes to 20 hours. Symptoms can occur.
Term
Stationary Phase
Definition
Cell Reproduction is balance by cell death. Nutrients become scarce. Toxins (Waste) build up creating Unfavorable conditions.
Term
Decline Phase (Death Phase)
Definition
No growth. Older bacteria will die first followed by new cells. may form, begin sporulation process. Nutrients are limited.
Term
Endospores
Definition
highly resistant structures coming from sporulation
Term
Sporulation
Definition
A process that a mother cell will wrap around new cell and new cell will become spore.
Term
Media
Definition
Microbiological medium used for culturing bacteria, molds, and other microorganisms. 1)Liquid 2) Solid 3) Semisolid
Term
Liquid Media
Definition
Tryptose Broth
Term
Solid Media
Definition
Tryptose Agar
Term
Semisolid Media
Definition
SS Media for Selmonela
Term
Factors affecting bacterial growth
Definition
1)pH 2)temperature 3)Oxygen Concentration
4)Osmotic Conditions
Term
Optimum pH
Definition
pH at which an organism grows best
Term
Acidophiles
Definition
Organisms whose Optimum pH is relatively to highly acidic. Acid-tolerant
Term
Neutrophiles
Definition
Organisms whose Optimum pH range is about pH7, plus or minus approx. 1.5pH units.
Term
Alkaphiles
Definition
Organisms whose optimum pH is relatively too highly basic
Term
Psychrophile
Definition
Cold adapted organisms. Grow at or below 20 degrees
Term
Mesophile
Definition
Organisms growth temp. is between 20°c-40°c
Term
Thermoduric
Definition
Can be exposed to a brief amount of heat.
Term
Thermophiles
Definition
High temp. adapted organisms. Multiply best at temps. around 60c but still multiply from 40°c to 70°c
Term
Obligate Aerobes
Definition
Need Oxygen to gas as a final electron acceptor to make cellular energy.
Term
Obligate Anaerobe
Definition
Few Fungal and Protozoal species. No Oxygen will be killed or inhibited if Oxygen is present.
Term
Microaerophiles
Definition
Survive in environments where the concentration of oxygen is relatively low
Term
Psychrotrophs / Psychrotolerant
Definition
Cold loving. Have a higher optimal growth temp. as well as a higher minimal and maximal growth temperature.
Term
Anaerobes
Definition
Microbes that do not or cannot use oxygen
Term
Aerotolerant
Definition
Insensitive to oxygen
Term
Hyperthermophiles
Definition
Grow optimally at temp. that exceed 80°c
Term
Asexual Cycle
Definition
DNA of the vegetative cell replicates and the cell elongates. Binary Fission
Term
Sporulation Cycle
Definition
Nutrient conditions become limiting, becoming spores
Term
Bacterial Growth Curve
Definition
Illustrates the events occurring over time
Term
Dipicolinic Acid
Definition
Organic substance that helps stabilize the proteins and DNA, after cell is/spore is engulfed by the mother cell.
Term
Facultative Microbes
Definition
Microbes can grow in either the presence or reduced concentration of oxygen.
Term
Thioglycollate Broth
Definition
A way to test an organisms oxygen sensitivity. Binds free oxygen so that only fresh oxygen entering the top of the tube would be available.
Term
Capnophilic Bacteria
Definition
Require an atmosphere low in oxygen but rich in carbon dioxide
Term
Barophiles
Definition
survive at high atmospheric pressure
Term
Nonhalophiles
Definition
Cells Unable to grow in the presence of salt
Term
Halophile
Definition
Cells Require salt to survive
Term
Halotolerant
Definition
Cells grow best with out salt, but can tolerate low concentrations of salt
Term
Extreme Halophiles
Definition
Cells tolerate salt concentration of 15 to 30%
Term
Agar
Definition
Polysaccharide derived from red algae. Contains no essential nutrients. Remains solid under 36ºC
Term
Complex Medium
Definition
Chemmicaly undefined medium contains nutrients in which the exact componnent or their quantity is not completely known medium
Term
Synthetic Medium
Definition
Precise chemical composition and amount of all components are known. Used to find organisms growth requirements.
Term
Differential Medium
Definition
Contains specific chemicals to indicate which species possess and which lack a particular biochemical process
Term
Enriched Medium
Definition
contains special nutrients for organisms containing complex nutritional requirments
Term
VBNC (Viable but not-culturable)
Definition
Impossible to estimate accurately microbial diversity in an environment based solely on culturability
Term
Biofilm
Definition
Mixed microorganisms with other species, in a so-called mixed culture
Term
Pure culture
Definition
A population consisting of only one species
Term
Pour plate method
Definition
Sterile dish.
Molten Agar medium added
Agar hardened
cells divide to form discrete colonies throughout agar.
Term
Streak Plate Method
Definition
Nutrient Agar plate.
Add bacteria with Loop
Term
Turbibity
Definition
Cloudiness
Term
Colony-forming units (CFUs)
Definition
Expressed as a number in a Standard plate count
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