Deck 31: Infection and Pathogenicity

Question 1

If a symbiont either harms or lives at the expense of another organism, the relationship is called

A) symbiosis.
B) parasitism.
C) commensalisms.
D) pathogenicity.

Answer 1

B

Question 2

An organism other than a human that is infected with a parasitic organism that can also infect humans is called a(n) ________ host.

A) reservoir.
B) endoparasite.
C) transfer.
D) intermediate.

Answer 2

A

Question 3

A __________ is an organism that transfers pathogens from one host to another.

Answer 3

vector

Question 4

An __________ pathogen can cause disease in a host with impaired resistance.

Question 5

Vector-borne transmission can be either external or internal. In external (mechanical) transmission, the pathogen is carried

A) on a fomite.
B) on the body surface of a vector.
C) within the vector.
D) all of the choices

Question 6

Which of the following is required of a pathogen to possess in order for it to be successful at causing infectious disease?

A) initially be transported to the host
B) be able to exit the host
C) ability to adhere to, colonize, or invade the host
D) ability to damage the host
E) all of the choices

Question 7

Which of the following has no effect on the outcome of the host-parasite relationship?

A) the number of parasites on or in the host
B) the virulence of the parasite
C) the defenses of the host
D) All of these have an effect on the outcome of the host-parasite relationship.

Question 8

Any organism that can cause disease in the host after direct interaction is a

A) focal pathogen.
B) opportunistic pathogen.
C) primary pathogen.
D) secondary pathogen.

Question 9

Bacteria within biofilms exchange

A) plasmids.
B) quorum-sensing molecules.
C) nutrients.
D) all of the choices

Question 10

An inanimate object that may be contaminated with a pathogen is called a

A) vector.
B) fomite.
C) zoonoses.
D) none of the choices

Question 11

Matching
1) latent
2) antitoxin
3) opportunistic
4) localized
A. requires weakened immune system
B. organisms present in tissue for long periods of time
C. not general infection
D. a neutralizing antibody

Question 12

The presence of viruses in the blood is called _______________.

Question 13

Matching
1) reservoir
2) fomite
3) opportunistic
4) nosocomial
A. does not harm a healthy host
B. develops during a hospital stay
C. site where the pathogen normally resides
D. inanimate object that may be involved in transmission

Question 14

Inanimate materials involved in pathogen transmission are called reservoirs.

Question 15

A ________________ infection is a disease caused by a parasitic organism that is normally found in animals other than humans.

Question 16

Transfer of pathogens from host to environment and then to another host are said to be transmitted _________.

Question 17

The final outcome of most host-parasite relationships depends on

A) the number of organisms present in or on the host.
B) the virulence of the organism.
C) the host's defenses.
D) all of the choices

Question 18

The condition in the host that results from pathogenic parasitic organism growing and multiplying within or on the host is called

A) an infection.
B) an infectious disease.
C) pathogenesis.
D) all of these.

Question 19

Which of the following is a facultative intracellular pathogen?

A) viruses
B) Brucella abortus
C) rickettsia
D) all of the choices

Question 20

Pathogens can penetrate to deeper tissues by producing specific virulence structures or enzymes. These products include all of the following except

A) collagenase.
B) ribosomes.
C) hyaluronidase.
D) leukocidins.

Question 21

A neutralizing antibody against a toxin is called a(n) __________.

Question 22

Cholera toxin is an AB toxin.

Question 23

The toxic component of lipopolysaccharide is called
A)

A) lipid
B) exotoxin.
C) hemolysin.
D) O antigen polysaccharide.

Question 24

Gas gangrene caused by Clostridium perfringens results from disruption of cell membranes caused by production of ____________.

Question 25

Generally, exotoxins tend to be more heat stable than endotoxins.

Question 26

Virulence may be measured experimentally at the host level by the __________ __________ __________, which measures the number of pathogens that kills 50% of an experimental group of hosts within a specified amount of time.

Question 27

Many types of bacteria are only _________ when dispersing from more stable and heterogeneous communities known as biofilms.

Question 28

Many bacteria are pathogenic because they carry large segments of DNA called __________ _________, which were acquired by horizontal gene transfer, and which carry genes responsible for virulence.

Question 29

The only organisms to produce endotoxins are gram-negative bacteria.

Question 30

Macrophages are phagocytic cells.

Question 31

While exotoxin production is most generally associated with gram-positive bacteria, some Gram-negative bacteria also produce exotoxins.

Question 32

Colonization specifically refers to the multiplication of a pathogen on or within a host, and includes the resulting tissue invasion and damage.

Question 33

The term __________ refers to the degree or intensity of pathogenicity.

Question 34

Because LPS is bound to the surface of bacteria, it is called a(n) __________.

Question 35

The capacity of an organism to produce a toxin is called __________.

Question 36

Fever response can be triggered by an endogenous pyrogen called interleukin-1.

Question 37

Once a pathogen has infected the host, __________________ is a measure of the pathogen's ability to spread to adjacent or other tissues.

Question 38

In the case of the AB toxins, the function of the B subunit is to

A) act as a neurotoxin.
B) have enzyme activity that causes toxicity.
C) act as a superantigen that stimulates T cells to release cytokines.
D) bind to host cell receptor.

Question 39

Listeria monocytogenes propels itself through mammalian host cells using:

A) a modified form of gliding motility.
B) host cell actin and other cytoskeletal proteins.
C) periplasmic flagella.
D) fimbriae based twitching motility.

Question 40

Exotoxins can be denatured by iodine to form __________ which are useful in vaccines.

Question 41

Endotoxin is released when

A) gram negative pathogens lyse or divide.
B) cells are starved for iron.
C) cells are lysogenic for the beta phage.
D) all of the choices

Question 42

Which of the following is not a biological effect associated with endotoxin?

A) coagulation
B) paralysis
C) fever
D) fibrinolysis

Question 43

By convention, when the word parasite is used without qualification, it often refers to

A) a protozoan or helminthic organism.
B) yeast or fungi.
C) Bacteria or Archaea.
D) lichens.

Question 44

Which of the following lyse erythrocytes to make iron available to pathogens?

A) hyaluronidase
B) collagenase
C) hemolysins
D) coagulase

Question 45

Endotoxins include which of the following?

A) diphtheria toxin
B) lipopolysaccharide
C) tetanus toxin
D) botulinum toxin

Question 46

An infectious disease process caused by bacterial or fungal toxins in the blood is called

A) septicemia.
B) systemic.
C) toxemia.
D) phytogenic.

Question 47

Which of the following is not a characteristic of lipid A?

A) heat stable
B) toxic in nanogram amounts
C) weakly immunogenic
D) neurotoxic

Question 48

Adherence factors (adhesins) that play a role in infectious diseases caused by gram negative bacteria include all of the following except

A) glycocalyx.
B) fimbriae.
C) lipoteichoic acid.
D) slime layer.

Question 49

The characteristics of a pathogen that determine its virulence include which of the following?

A) pathogenicity
B) invasiveness
C) infectivity
D) all of the choices

Question 50

Pathogenicity islands are typically associated with

A) genes encoding tRNA.
B) genes encoding rRNA.
C) G+C content similar to the rest of the bacterial genome.
D) none of the choices