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