Chapter 7 Fundamentals of Microbial Growth Flashcards
Cell division that produces new daughter cells and increase the total cell population.
Microbial growth
Another method of asexual reproduction that certain fungi and some bacteria such as Hyphomicrobium reproduce this way.
Budding
A type of formation that can be sexual or asexual while in bacteria it is asexual.
Spore formation
The time it takes for a particular species of cell to divide.
Generation time
As bacteria divide by binary fission, one cell turns to two, two to four, four to eight and so on.
Exponential
Cells alter their gene expression in response to their new setting. For example they make new enzymes and transporter proteins so that they can take up and metabolize nutrients provided in their new environment
Lag Phase (1)
If the growth conditions are optimized for nutrients, pH level and temperature, then once the cells have adjusted to their new environment, then will enter a phase of rapid exponential growth.
Logarithmic or Log phase (2)
The population growth rate slows and eventually levels off as the number of cells dying matches the number of cells dividing.
Stationary phase (3)
A critical point of waste buildup and decreasing nutrients, the cell begins to die.
Death Phase (4)
Fresh growth medium is added at one end of the culturing device, while waste, nutrient-depleted medium, and excess cells are removed at another end fate system to maintain a constant culture volume.
Chemostat
Organisms that tend to live in environments that are consistently cold like the Arctic. Temperatures ranging -20C to 10C.
Psychrophiles
These grow in 0-30C temperatures and are associated with food-borne illnesses because they can grow in refrigerator and frozen foods.
Psychrotrophs
These grow in between 10-50C which includes the body temperature. Found on the soil to streams to dwelling in eukaryotic systems.
mesophiles
Typically found in compost piles and hot springs with temperatures ranging form 40-75C.
Thermophiles
These prefer extremely hot temperatures ranging from 65-120C. These organisms are found in boiling water and volcanic vents.
Extreme thermophiles
Bacteria that live near thermal’s vents are not only extreme thermophiles and have the ability to withstand the high pressure environment of the deep sea.
Barophiles
Organisms that survive in high Salt environments.
Halophiles
Reactive intermediates that include superoxide ions and hydrogen peroxide, both of which can rapidly damage cellular proteins and DNA.
Reactive oxygen species ROS
Microbes that have the ability to detoxify ROS and safely use oxygen in their metabolism.
Aerobes
Organisms that have an absolute dependence on oxygen for cellular processes and will die unless it is abundant.
Obligate aerobes
Organisms that require small amounts of atmospheric oxygen and live in low oxygen settings where they can limit their exposure to ROS while still meeting their oxygen needs.
microaerophiles
Organisms that do not require the use of oxygen in their metabolic processes.
Anerobes
A group of microbes that span both aerobic and anaerobic environments. Switch hitters.
Facultative anaerobes
Elements such as carbon, hydrogen, nongaseous oxygen and nitrogen are regard to build new cells and can be found in the organic and inorganic compounds microbe’s environment.
Essential nutrients
Requires and external source of organic carbon scubas sugars, lipids, and proteins.
Heterotrophs
Organisms known as self feeding that use a process called carbon fixation
Autotrophs
The process to convert inorganic carbon into organic carbon.
Carbon fixation
A process that can convert atmospheric nitrogen from a gas form to a non gaseous form like ammonia that can be used by other cellular life.
Nitrogen fixation
The necessary substances that a cell can’t make on its own.
Growth factors
Organisms that are need multiple growth factors.
Fastidious
Organisms that use light energy
phototrophs
Organisms that break down chemical compounds for energy
chemotrophs
Cooled at an angle in a test tube
slants
cooled in an upright position
deep
Useful for growing certain autotrophs and some heterotrophs. Chemically defined or precisely known composition.
defined media
Used to grow fastidious organisms with complex growth requirements. Contains a mixture of organic and inorganic nutrients that are not fully defined.
Complex media
Media formulated to visually distinguish one microbe from another.
Differential media
A common example of a differential medium contains sheep red blood cells that serve as both a nutrient and a differentiation indicator.
Blood Apgar
Breaks down red blood cells
Beta hemolytic
Partial breaks down red blood cells
alpha hemolytic
do not lyse red blood cells
gamma hemolytic
A process that singles out bacteria that have specific properties.
selective media
Most bacteria can not grow on this medium due to its high salt content.
mannitol salt agar MSA
Methods designed to prevent the introduction of contaminating microbes to a patient, clinical sample or others in the health care setting.
Aseptic techniques
A method or technique that isolates bacteria to identify the potential pathogen in a clinical sample.
Streak plate technique
As cells divide their population increases to form a mound of cells known as
A colony
Enumerates the number of cells in a small portion of the sample, and can be done using automated or manual procedures
Cell count
Allows for direct enumeration of bacteria using agar plates. Applied to agar using either the spread plate method or pour plate method. After the incubation period, colonies are visible and can be counted.
Viable plate count
A fast and easy way to indirectly measure cell number is to measure ____ of a liquid culture.
Turbidity
Removes or reduces microbial populations to rend an object safe for handling.
Decontamination
Eliminates all bacteria, viruses and endospore. Required for drugs. Objects used for medical procedures, and for lab media and glassware.
Sterilization
Reduces microbial numbers. Used for cosmetics, foods, surfaces, and external medical equipment.
Disinfection
The shortest period of time that a given temperature must be held to kill all microbes in a sample.
Thermal death time
The minimum temperature needed to kill all microbes in a sample within ten minutes.
Thermal death point
A machine that applies steam heat along with pressure to sterilize microbiological media and assorted medical or lab equipment.
Autoclave
Formed when free floating bacteria adhere to a surface.
Biofilm
A type of communication for bacteria to determine if their population is large enough to attack more tissue with the enzyme.
Quorum Sensing
