CHAP 8 Flashcards
TRUE/FALSE
All living organisms require nutrients to sustain life.
TRUE
What is needed to carry our normal metabolic processes?
Water
What are microorganisms that grow best at high temperatures?
Thermophiles
What are microbes that grow best at moderate temperatures?
Mesophiles
What prefers cold temperatures like deep ocean water?
Psychrophiles
What do you call a particular group of psychrophiles, that prefer refrigerator temperature like 4 degrees celsius?
Psychotrophs
What prefer warm temperatures but can endure very cold or even freezing temperatures?
Psychroduric organisms
What refers to the acidity or alkalinity of a solution?
pH
TRUE/FALSE
Some microorganisms prefer a neutral or slightly alkaline growth medium.
FALSE (Most)
What prefers a pH of 2 to 5?
Acidophiles
What prefer a pH of >8.5?
Alkaliphiles
What is the pressure that is exerted on a cell membrane by solutions both inside and outside the cell?
Osmotic pressure
What is the movement of a solvent, through permeable membrane, from a lower concentration of solutes to a higher concentration of solutes?
Osmosis
What is a condition in which the cell membrane and cytoplasm of a cell shrink away from the cell wall?
Plasmolysis
What occurs when bacteria with rigid cell walls are placed in a hypertonic solution?
Plasmolysis
When the concentration of solutes outside a cell is less than that of solutes inside a cell, the solution in which the cell is suspended is called?
hypotonic
If a bacterial cell is placed into a hypotonic solution and bursts, the cytoplasm escapes and this process is called?
plasmoptysis
A solution is said to be ________ when the concentration of solutes outside a cell equals the concentration of solutes inside the cell.
isotonic
Organisms that prefer to live in salty environments are called?
halophilic organisms
Organisms that do not prefer to live in salty environments but are capable of surviving in salty environments are called?
haloduric organisms
What prefer the same atmosphere that humans do?
Obligate aerobes
What require reduced concentrations of oxygen?
Microaerophiles
What are killed by the presence of oxygen?
Obligate anaerobes
What require increased concentrations of CO2?
Capnophiles
Bacteria divide by _____________ (one cell divides to become two cells) when they reach their optimum size.
Binary Fission
The time it takes for one cell to become two cells is called the?
generation time
What are used in microbiology laboratories to culture bacteria?
Media
If media is prepared in the laboratories, they are referred to as?
Artificial media or synthetic media
TRUE/FALSE
A chemically defined medium is one in which all ingredients are known.
TRUE
What is a broth or solid containing a rich supply of special nutrients that promote the growth of fastidious organisms, for example, chocolate agar?
Enriched medium
What has added inhibitors that discourage growth of certain organisms while allowing the growth of a desired organism, for example, PEA agar?
Selective medium
What is a popular liquid medium in bacteriology laboratories; it supports the growth of all categories of bacteria from obligate aerobes to obligate anaerobes?
Thioglycollate (THIO) broth
What involves adding a portion of a specimen to the medium?
Inoculation
Unwanted organisms are referred to as?
Contaminants
After media are inoculated, they must be placed into an ________ which will maintain the appropriate atmosphere, temperature, and moisture level.
Incubator
What are the 3 types of incubators used in clinical microbiology laboratories?
- CO2 incubator
- non-CO2 incubator
- anaerobic incubator
What can be used to determine growth by measuring the turbidity of the medium?
spectrophotometer
What is used to determine the number of viable bacteria in a liquid sample by making serial dilutions of the liquid and inoculating onto nutrient agar; after overnight incubation, the number of colonies is counted?
viable plate count
TRUE/FALSE:
A population growth curve for any particular species of bacterium may be determined by growing a pure culture of the organism in a liquid medium at a constant temperature.
TRUE
What is prepared by plotting the logarithmic number of viable organisms against the incubation time?
Graph
Obligate intracellular pathogens are microbes that can survive and multiply only within?
Host cells
What is the complete destruction of all microbes, including cells, spores, and viruses?
Sterilization
What is the destruction or removal of pathogens from nonliving objects by physical or chemical methods?
Disinfection
What are chemical substances that eliminate pathogens on inanimate objects?
Disinfectants
What are solutions used to disinfect skin and other living tissues?
Antiseptics
TRUE/FALSE
Bactericidal agents are chemicals that specifically kill bacteria, but not necessarily bacterial endospores.
TRUE
What is a drug or chemical that inhibits growth and reproduction of microbes?
microbistatic agent
What drug is one that specifically inhibits the metabolism and reproduction of bacteria?
bacteriostatic agent
What is a process that combines dehydration (drying) and freezing?
This process is widely used in industry to preserve foods, antibiotics, microorganisms, and other biologic materials
Lyophilization
What refers to the presence of pathogens in blood or tissues, whereas asepsis means the absence of pathogens?
Sepsis
What is the prevention of infection?
Antisepsis
What factors determine the
effectiveness of heat for sterilization?
- Temperature
- Time
What is a large metal pressure cooker that uses steam under
pressure to completely destroy all microbial life?
Autoclave
What do you call the process when many dried microorganisms remain viable, but they cannot reproduce?
Desiccation
What is used in hospitals and medical and dental clinics to clean equipment?
Ultrasonic waves
What refers to the use of chemical agents to inhibit the growth of pathogens, either temporarily or permanently?
Chemical disinfection
