Micro exam II Flashcards
The process in which all living cell and non-living disease agents (spores, viruses, etc.) are eradicated from an object or a place
sterilization
The removal or inhibition of disease-causing microbes from an object or place
disinfection
The process in which microbial levels are reduced to non-hazardous levels as defined by public health board
sanitization
A chemical that wipes out all living cells and non-living disease agents
sterilant
An agent that wipes out most microbes (never spores and some resistant microbes do existant)
disinfectant
An agent that doesn’t kill all cells. It is used to prevent infection or sepsis of a living tissue by microbes.
antiseptic
Compounds that are made by microbes to kill bacterial competitors. They are selectively toxic to prokaryotic cells and have no effect on non-cellular disease-causing agents (viruses)
antibiotics
Any antifungal agent
antimycotic
An agent that selectively disrupts viral DNA replication more than it disrupts eukaryotic DNA replication
Antiviral
what does the suffix “-cide” mean in terms of antimicrobial agents
kills bacteria, but the cells remain intact
what does the suffic “-lytic” mean in terms of antimicrobial agents?
Kills bacteria by lysis fo the cells
What does the suffix “-static” mean in terms of antimicrobial agents
suspends growth of cells, leaving them intact. Once the agent is removed, cells will begin to grow again.
What are the seven environmental factors that affect attempts to control microbial growth?
- Size of the population
- Composition of the population
- Concentration of the antimicrobial agent used
- Length of exposure to antimicrobial agent
- Temperature
- Composition of the local environment
- Type of microbe
How does the chemical control method phenolics work?
- denature proteins in microbes
- disrupt cell membranes
The microbial growth curve phase in which the inoculum has occurred and there is no increase in the amount of bacterial cells. Cells are growing larger and are metabolically active
Lag phase
The microbial growth phase in which cells are actively dividing by binary fission and their numbers are increasing exponentially
log phase
The microbial growth curve phase in which the number of new cells created by cell division is equal to the number of cells dying. Cells are dying due to waste product accumulation and nutrients being used up. The gradual depletion of oxygen begins to limit cell growth.
Stationary phase
The microbial growth curve phase in which more cells are dying than cells that are being produced. Viable count decreases exponentially
death or decline phase
Direct count
a method of counting cells that counts individual cells by looking at them under a microscope or by counting colonies on a plate
indirect count
a method of counting cells that depends on measurement of cell presence or activity without actually counting individual cells.
Viable count
The number of alive cells
Total count
the number of bacterial cells in a culture, both live and dead
An indirect method of counting cells that looks at how cloudy or turbid a sample is
Optical Density
The time it takes for the population to double through one round of binary fission
Generation time or doubling time
What mechanism is used by alcohols to disrupt microbial growth?
- Denatures proteins
- Destroys membranes by dissolving lipids
What mechanism is used by halogens to disrupt microbial growth?
- Oxidizes cell membranes and organelles
- Can halogenate proteins, making them inactive
What mechanism is used by heavy metals to disrupt microbial growth?
Denaturation of proteins by combining with sulfhydryl groups
What mechanism is used by quats (quaternary ammonium compounds) to disrupt microbial growth?
Each molecule has a polar and nonpolar region. Quats with long non-polar regions can disrupt plasma membranes (causing lysis)
What mechanism is used by aldehydes to disrupt microbial growth?
“fix” tissues and cells by denaturing membrane-bound and cytoplasmic proteins of the cell
what mechanism is used by gas sterilization to disrupt microbial growth?
denatures proteins in both spores and vegetative cells
What are fomites?
Inanimate object which carry germs/microbes from one place to another. Example: door knobs, toys, towels, toilet handle, used bandage, etc.