Exam 3 - Multiple choice

The series of steps used to connect an organism to a disease are known as

Koch's postulates

The microorganisms that are regularly found in or on the body, yet do not apparent harm are called

normal microbiota

the microorganisms that are occasionally found in or on the body are called

transient microbiota

a relationship in which one partner benefits and the other is harmed is termed

parasitism

which of the following is true about the role normal microbiota plays in maintaining host health?

-they produce antimicrobial substances
-they establish competition for nutrients and vitamins
-they provide a surface that is incompatible for attachment of an invade
-they stimulate the immune system

the composition of the normal microbiota may be affected by

-diet
-use of antibiotics
-hormonal changes
-obesity level

the first step in the establishment of infection is that the organism must

attach to host cells

the lack of susceptibility to diseases of other species in humans may be due to the

lack of receptors that are recognized by adherence factors

the chemical nature of endotoxins is that of a

lipopolysaccharide

which is sure about super antigens?

they are a type of exotoxin AND they bind the MHS class II antigen on T cells

The damage cause by parasites may be due to

-the direct digestion of host tissue
-the hosts immune response
-competition for nutrients
-the physical blocking of organs

the last case of naturally contracted smallpox occurred in

antigen or antibody

an immune complex is defined as

antigen combined with antibody

the number of cases of a specific disease per one hundred people exposed is called the

attack rate

the fraction of a population who die from a specific disease is called

mortality rate

a cluster of cases in a specific population occurring in a brief period of time is called a(n)

outbreak

important sources of contamination in crowded locations are

droplets of saliva or mucus

when an infectious disease cannot spread in a population because it lacks a significant number of susceptible hosts, the phenomenon is referred to as

herd immunity

the type of epidemiological study that determines the characteristics of the persons involved and the time and place of the outbreak is called a(n)

descriptive study

so far, the only disease that has been globally eradicated is

smallpox

an infection acquired during hospitalization is referred to as

nosocomial

the antimicrobials produced by some molds and bacteria are generally called

antibiotics

the rate of elimination of an antimicrobial is expressed as its

half-life

antimicrobials may produce

-allergic reactions
-suppression of normal microbiota
-toxic effects

the lowest concentration of drugs that prevents growth of a microorganism is the

minimum inhibitory concentration

bacteria may become antibiotic resistant due to

-alteration in the target molecule
-decreased uptake of the drug
-drug-inactivating enzymes
-increased elimination of the drug

the most common method of transfer of antimicrobial resistance is through the use of

r plasmids

which of the following bacteria have an innate resistance to penicillin?

mycoplasma

antibiotics that are most likely to disrupt the normal microbiota are termed

broad-spectrum

drugs that are most effective when taken together are called

synergistic

the first identified case in an outbreak is called the

index case

if the number of people who become ill during an epidemic rises and falls rapidly, this is a called a(n)

common source epidemic

if the number of people who become ill during an epidemic rises gradually, this is called a(n)

propagated epidemic

because of natural evolution of microorganisms, it is necessary to use techniques that allow distinguishing them at the level of

strain

the period of time between exposure to an agent and the onset of disease signs and symptoms is called the

incubation period

apparently healthy people who may transmit a pathogen they harbor are called

carriers

which of the following is considered a zoonotic disease?

plague

vertical transmission involves

pregnant woman to fetus

almost all of the antibodies found in a newborn are

the result of passive immunity

the chemical nature of exotoxins is that of a

protien

an example of genetic variation used in pathogen survival may be

changing the pilus type

bacteria may survive phagocytosis by

preventing fusion of the lysosome with the phagosome AND lysing the phagosome

which of the following factors is not considered important for the establishment of an infection

toxicity

typically, adhesins

are found in pili, help bacteria attach to host cells, AND are the protiens

growth of a parasitic organism in or on the host is referred to as

infection

a disease causing microorganism or virus is referred to as a(n)

pathogen

opportunists or opportunistic pathogens

take advantage of special circumstances

the suffix -emia means in the

blood

a more modern equivalent to Koch's postulates is termed

molecular postulates

newborn babies acquire microbiota by

-breastfeeding
-contact with mothers skin
-environment
-passing through the birth canal