MICROBIOL: Chapter 11
which root indicates the ability to kill microorganisms
-cide
are chemical agents applied directly to body surfaces to inhibit vegetative pathogens
antiseptics
is a term referring to a condition free of pathogenic microorganisms or a procedure or process designed to prevent entry of infectious agents
asepsis
Any process or agent that inhibits bacterial growth
bacteristatic
a ___ agent will inhibit the growth of bacteria, whereas a ___ agent will kill bacteria
bacteristatic; bactericidal
a critical concern for the food packaging industry is the elimination of endospores of
clostridium botulinum
if an agent disrupts the cell wall, the cell is likely to experience
death by lysis
is the physical removal of surface oils, debris, and soil from skin to reduce the microbial load
degermation
the disruption of proteins from their native state is known as
denaturation
a bactericide ___ bacteria
destroys
which items can be sanitized by boiling water prior to safe, acceptable use in humans
drinking water bedding and clothing utensils
___ heat requires longer exposure times and higher temperatures than ___ heat
dry; moist
ionizing radiation is not an effective method of controlling microbes in food products
false
pasteurization is the destruction of microbes by subjecting them to extremes of dry heat, reducing them to ashes and gas
false
the characteristics of a microbial population targeted for control do not include microbes with variable resistance
false
the effectiveness of an antimicrobial agent is only governed by the time of exposure to the agent
false
the shortest length of time required to kill all test microbes at a specified temperature is referred to as the thermal death point
false
the primary targets of microbial control are microorganisms that cause ___ or ___
food spoilage, disease
a sterile object is
free of all viable microorganisms and viruses
an agent that kills fungal spores, hyphae and yeasts is called a
fungicide
in what unit is radiation measured
grays
is the most common physical agent used to control microbes
heat
which four of the following are examples of physical agents or mechanical means used to control microbes
heat, cold, filtration, radiation
the use of sugar or salt to preserve food creates a ___ environment for the bacteria in the foods
hypertonic
virucides ___ viruses
inactivate
is a dry heat method that is commonly used in student laboratories to sterilize inoculating loops and wires
incineration
what are the effects of adding pressure to water in an autoclave
increases boiling point of water increases temperature of steam
___ is a good technique for sterilizing materials that are sensitive to heat or chemicals
ionizing radiation
what type of radiation consists of short-wave electromagnetic rays (such as X rays) that cause ejection of electrons from target molecules and the creation of ions
ionizing radiation
the two types of macromolecules that make up the majority of the cell membrane in organisms are ___ and ___
lipids; proteins
filtration is used to prepare ___ that cannot be heated, and to remove ___ contaminants that are a common source of infection and spoilage
liquids; airborne
if an agent disrupts the cell wall, the cell is likely to experience death by
lysis
which of the following is not a way that a chemical control agent damages a cell wall
making it more permeable (leaky)
an agent's effect on cells is known as its ___ of action
mechanism
the cell ___ is responsible for preventing the loss of important molecules and stopping the entry of damaging substances
membrane
younger, active cells die more quickly when exposed to microbicidal agents because they are more ___ active
metabolically
involves the permanent termination of a particular organism's vital processes, and special qualifications are often needed to define and delineate this phenomenon in microbes
microbial death
any process or agent that inhibits microbial growth is referred to as
microbistatic
in terms of using heat as an agent of microbial control, ___ heat methods operate at lower temperatures and
moist; dry
the normal 3-dimensional state of a protein is called its ___ state
native
sterilization is
only necessary for certain groups of microbes generally reserved for inanimate objects
disinfection destroys
only vegetative bacterial cells
methods for controlling microorganisms include heat, pressure, and radiation
physical
which three factors can influence the action of antimicrobial agents
presence of interfering matter temperature of environment microbial load
what factor must be considered in order to adequately sterilize using heat
presence of water temperature length of exposure
which of the following compounds are commonly used as gaseous sterilants or disinfectants
propylene oxide ethylene oxide chloride dioxide
the four general cellular targets of antimicrobial agents are the cell wall, the cell membrane, nucleic acid synthesis, and ___ function
protein
nucleic acids are involved in the process of translation to synthesize ___, DNA-encoded amino acids
proteins
thymine, uracil and cytosine are called ___, which are a type of nitrogenous bases found in either DNA or RNA
pyrimidines
the inability to ___ is the practical definition of microbial death
reproduce
which are goals of pasteurization
retention of liquid qualities reduction of microbial load
which cellular structure is involved in translation
ribosome
is a decontamination technique that mechanically removes microorganisms and debris from inanimate objects to reduce contamination to safe levels
sanitization
boiling water can be an effective means of ___ in the clinic and home
sanitization; disinfection
which of the following describes the main function of the cell membrane
selective barrier
is defined as growth of microorganisms in the blood or other tissues
sepsis
the main effect of cold treatment is to
slow the activity of microbes
a ___ is an agent that can destroy bacterial endospores
sporicide
a process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat is referred to as
sterilization
the ___ and ___ levels of protein structure are disrupted in denaturation
tertiary; secondary
in general, planktonic bacteria are more susceptible to control agents than biofilm bacteria because
the extracellular biofilm matrix provides protection from control agents
disinfectants are normally only used on inanimate objects because
the high concentrations needed are harmful to living tissues
a surfactant is an agent that disrupts the lipid bilayer of membranes and alter the membrane's permeability
true
an autoclave is a sterilization chamber that allows the use of stream under pressure to sterilize materials
true
an object is either sterile or not sterile
true
antimicrobial solutions with alcohol or water-alcohol mixtures as the solvent are called tinctures
true
radiation is energy emitted from atomic activities and dispersed at high velocity through matter or space
true
the lowest temperature that achieves sterilization in a given quantity of broth culture upon a 10-minute exposure is referred to as the thermal death point
true
the necessity of sterilization or disinfection should be considered when initially choosing a method of microbial control
true
___ radiation is a type of nonionizing radiation and is routinely used to disinfect air and the surfaces of solid objects
ultraviolet