Ch.6 Microbial Growth Flashcards
Physical Requirement for Growth:
~ Temperature
* Minimum growth temperature is the — temperature are which the species — grow
* Optimum growth temperature is temperature at which the species grows —
* Maximum growth temperature is the — temperature at which the species will grow
- Lowest
- Will
- Best
- Highest
Temperature:
~ —, cold loving
~ —, moderate temperature loving
~ — heat loving
- Psycrophiles
- Mesophiles
- Thermophiles
Temperature:
~ Psychotrophs
* Grow between — and — to —
* Cause ——
- 0 Celsius
- 20 to 30 Celsius
3.Food Spoilage
Temperature:
~ Thermophiles:
*Optimum growth temperature — to —
* Found in —— and ——
~ Hyperthermophiles:
* Optimum growth temperature >—
* Live in —— associate with — activity
- 50 to 60 Celsius
- Hot Springs
- Organic Compost
- 80 Celsius
- Hot Springs, Volcanic
pH:
~ Most bacteria grow between pH — and —
~ Molds and yeasts grow between pH — and —
~ — grow in acidic environments
~ Very few bacteria grow at an acidic pH below about pH —. This is why a number of foods, such as sauerkraut, pickles, and many cheese, are preserved from spoilage by acids produced by bacterial fermentation
- 6.5 & 7.5
- 5 & 6
- Acidophilus
- 4
Osmotic Pressure:
~ Hypertonic environment (higher in solutes than inside the cell) cause — due to — osmotic pressure
~ — or —— require high osmotic pressure (high salt)
~ —— tolerate high osmotic pressure
~ If the osmotic pressure is unusually low (—) such as in distilled water, for example water tends to enter the cell. Some microbes that have a relatively weak cell may be —
- Plasmolysis
- High
- Extreme or obligate halophiles
- Facultative Halophiles
- Hypotonic
- Lysed
Chemical Requirements:
~ Carbon
* —— of organic molecules
* — use organic molecules as energy
* — use CO2
- Structural backbone
- Chemoheterotrophs
- Autotrophs
Chemical Requirements:
~ Nitrogen:
* Component of —, —, and —
* Most bacteria — protein material for the nitrogen source
* A few bacteria use N2 in ——
- Proteins, DNA, & ATP
- Decompose
- Nitrogen Fixation
Chemical Requirements:
~ Sulfur:
* Used is ——, —, and —
* Most bacteria — protein for the sulfur source
* Some bacteria use — or —
- Amino Acids, Thiamine, Biotin
- Decompose
- SO4 -2 or H2S
Chemical Requirements:
~ Phosphorus:
* Used in —, —, and —
* Found in —
* — is a source of phosphorus
- DNA, RNA, and ATP
- Membranes
- PO4 3-
Trace Elements:
~ — elements required in small amounts
~ Usually ——
~ Include —, —, —, and —
~ Most are essential for the function of certain —
- Inorganic
- Enzyme Cofactors
- Iron, Copper, Molybdenum, and Zinc
- Enzymes
Siderophores:
~Availability of — often limits microbial growth
~ Living tissue is a particularly poor source of available —
~ Many bacteria acquire — by releasing —— components called siderophores
- Iron
- Iron
- Iron
- Iron-solubilizing
Oxygen:
~ —— require oxygen
Obligate Aerobes
Oxygen:
~ —— grow via fermentation or anaerobic respiration when oxygen is not available
Facultative Anaerobes
Oxygen:
~ —— unable to use oxygen and are harmed by it
Obligate Anaerobes
Oxygen:
~ —— tolerate but cannot use oxygen
Aero tolerant Anaerobes
Oxygen:
~ — require oxygen concentration lower than air
Microaerophiles
Oxygen Effect:
~ Superoxide Dismutase:
* Destroys — by converting it into — and ——
- Superoxide
- Oxygen
- Hydrogen Peroxide
Oxygen Effect:
~ Catalase:
* Destroys —— by converting it into — and —
- Hydrogen Peroxide
- Oxygen
- Water
Biofilms:
~ Microbial —
~Form — or — that adhere to surfaces
*Bacteria communicate cell-to-cell via — sensing
~— nutrients
~Shelter bacteria from — environmental factors
~Found in digestive system and sewage treatment systems; can clog pipes
~ — resistant to microbicides
~ Involved in —% of infections
~ Catheters, heart valves, contact lenses, dental caries
- Communities
- Slime or Hydrogels
- Quorum
- Share
- Harmful
- 1000X
- 70
Culture Media:
~ Culture Medium: — prepared for microbial —
- Nutrients
- Growth
Culture Media:
~ Sterile: —— microbes
No living
Culture Media:
~ Inoculum: — of microbes into a —
- Introduction
- Medium
Culture Media:
~ Culture: Microbes — in or on a culture medium
Growing
Culture Media:
~ Agar:
* ——
* Used as a — agent for culture media in petri plates, slants, and deeps
* Generally not — by microbes
* Liquefies at —
* Solidifies at ~—
- Complex Polysaccharide
- Solidifying
- Metabolized
- 100 Celsius
- 40 Celsius
Culture Media:
~ Chemically defined media: — chemical composition is —
* — organisms are those that require many growth factors provided in chemically defined media
1.Exact
2. Known
3. Fastidious
Culture Media:
~ Complex Media: — and — of yeasts, meat, or plants; chemical composition varies batch to batch
* —— & ——
- Extracts and Digest
- Nutrient Broth & Nutrient Agar
Special Culture Techniques:
~ —
* Microbes that require —— conditions
* — packet
* Candle Jar
- Capnophiles
- High CO2
- CO2
Selective and Differential Media:
~ Selective Media
* — unwanted microbes and — desired microbes
* Contain — to suppress growth
- Supress
- Encourage
- Inhibitors
Selective and Differential Media:
~ Differential Media:
* Allow distinguishing of colonies of — microbes on the — plate
~ Some media have both selective and differential characteristics
- Different
- Same
Enrichment Culture:
~ Encourages the growth of a desired microbe by — very — number of a desired organism to detectable levels
~ Usually a —
- Increasing
- Small
- Liquid
Obtaining Pure Cultures:
~ A pure culture contains only — species or strain
~ A colony is a — of cells arising from a — cell or spore or from a — of attached cells
~ A colony is often called a ———
~ The streak plate method is use to isolate ——
- One
- Population
- Single
- Group
- Colony-forming unit (CFU)
- Streak Plate Method
Bacterial Division:
~ Increase in — of cells, not cell —
~ ——
~ —
~ — (actinomycetes)
~ Fragmentation of —
- Number
- Size
- Binary Fission
- Budding
- Conidiophores
- Filaments
Generation Time:
~Time required for a cell to divide
* — minute to — hours
~ Binary fission — the number of cells each generation
~ Total number of cells= —— of generation
~ Growth curves are represented —
~ ——(——) is the period required for cells in a microbial population to enlarge, divide, and produce two new cells for each that existed before
- 20 minutes to 24 hours
- Doubles
- 2 number
- Logarithmically
- Doubling time (generation time)
Phases of Growth:
~ Lag phase: there is — or — change in the number of cells, but — activity is high
- little or no
- Metabolic
Phases of Growth:
~ Log Phase: The bacteria — at the — rate possible under the condition provided
- Multiply
- Fastest
Phases of Growth:
~ Stationary Phase: There is an — between —— and —
- Equilibrium
- Cell division
- Death
Phases of Growth:
~ Death Phase: the number of — exceeds the number of — cells formed
- Death
- New
Plate Counts:
~ A standard plate count reflects the number of —— and assumes each bacterium
~ Grows into a ——; plate counts are reported as number of colony-forming units (CFU)
~ To ensure the right number of colonies, the original inoculum must be diluted via ——
~ Counts are performed on bacteria mixed into a dish with agar (———) or spread on the surface of a plate (———)
- Viable Microbes
- Single Colony
- Serial Dilution
- Pour Plate Method
- Spread Plate Method
Quorum Sensing: the ability of bacteria to — and — their behavior
- Communicate
- Coordinate
Filtration:
~ Can be used when the quantity of bacteria is very —
~ Solution passed through a filter that collects —
~ Filter is transferred to a Petri dish and grows as — on the surface
- Small
- Bacteria
- Colonies
The Most Probable Number (MPN) Method:
~ — tube test
~ Count — tubes
~ Compare with a — tube
- Multiple
- Positive
- Statistical
Direct Microscopic Count:
~ — of a bacterial suspension placed on a slide
~ —— of bacteria per viewing field is calculated
~ Uses a special —— cell counter
- Volume
- Average Number
- Petrify-Hausser
Estimating Bacterial Numbers by Indirect Methods:
~ Turbidity: measurement of — with a spectrophotometer
~ Metabolic Activity: amount of metabolic product is — to the number of bacteria
~ Dry Weight: bacteria are —,—, and —; used for — organisms
- Cloudiness
- Proportional
- filtered, dried, and weighed
- Filamentous
