Deck 2: Hostparasite Interaction

Question 1

The smaller the number of microorganisms necessary to cause infection in a competent host, the more _____ the microorganism.

A) opportunistic
B) parasitic
C) invasive
D) virulent

Answer 1

D

Question 2

Parasitism is

A) a biological relationship between two or more organisms in which both benefit from one another.
B) a biological relationship between only two organisms in which there are no beneficial or harmful effects to the host.
C) a biological relationship in which one species gains benefits at the expense of the host.
D) a synonym for mutualism.

Answer 2

C

Question 3

A laboratory professional is testing a new antimicrobial soap. The tech washes her forearm then does a culture of the skin. Which organisms should she most likely expect to find growing in the culture?

A) Diphtheroids and Bacillus spp.
B) Staphylococcus epidermidis and Propionibacterium
C) S. aureus and Propionibacterium
D) Diphtheroids and Propionibacterium
E) None of these organisms should be found.

Answer 3

B

Question 4

Diabetics may sometimes be infected with their own resident flora. This type of infection is called

A) an opportunistic infection.
B) a carrier state.
C) symbiosis.
D) a parasitic infection.

Question 5

This type of bacteria is able to live in the colon with little to no oxygen and is the predominant organism.

A) Anaerobes
B) Facultative anaerobes
C) Facultative gram-negative rods
D) Gram-positive cocci

Question 6

What mechanism allows strict anaerobes to grow in the cervices and areas between the teeth when plaque is present?

A) A low oxidation-reduction potential occurs at the tooth surface under the plaque.
B) The bacteria secrete sugar to nourish the strict anaerobes.
C) The normal flora secrete antibiotics to kill all the other bacteria and allow the strict anaerobes to thrive.
D) The plaque-causing bacteria secrete an alkaline fluid and change the pH around the tooth.

Question 7

Healthy people are colonized by many different bacteria in many different sites. These bacteria are referred to as

A) transient flora.
B) carrier flora.
C) maintenance flora.
D) indigenous flora.

Question 8

The ability of an organism to produce disease in an individual is called

A) pathogenicity.
B) iatrogenic infection.
C) parasitic infection.
D) opportunistic infection.

Question 9

Changes in these host structures can result in lower virulence of a microorganism.

A) Pili
B) Adhesin receptors
C) Surface polysaccharides
D) Phagocytes

Question 10

The most common bacterial characteristic that allows for evasion of phagocytosis by the host is called

A) exotoxin production.
B) extracellular enzyme production.
C) pili.
D) polysaccharide capsule.

Question 11

The human body is constantly challenged by pathogens in the environment. It is not infected by every pathogen it encounters because the microbial flora

A) engulf the pathogenic bacteria.
B) produce conditions at the microenvironmental level that block colonization.
C) prime our immune system.
D) activate and support the action of antigen-presenting cells, cytokines, and cell-mediated immunity.

Question 12

Organisms that participate in a biological relationship where both benefit from one another are called

A) parasites.
B) symbionts.
C) hosts.
D) flora.

Question 13

A patient with an indwelling catheter develops a fever and lethargy. In addition, the urine in the catheter bag has turned a brownish color and smells foul, which suggests an infection is present. What type of infection does this describe?

A) Opportunistic
B) Iatrogenic
C) Pathogenic
D) Parasitic

Question 14

After attachment to host cells, a pathogen may use the following mechanisms to establish itself and cause disease, except:

A) Uses lactoferrin for iron
B) Produces an IgA protease that degrades the IgA at mucosal surfaces
C) Produces lysozyme to kill the host cell
D) Circumvents host antibodies by shifting key cell-surface antigens

Question 15

This is a leukocidin that is lethal to leukocytes and produced by staphylococci.

A) Panton-Valentine
B) Lancefield
C) Hemolysin
D) Adhesins

Question 16

After perforation of the colon, surgeons must guard against infection in the _____ because of leakage of the contents of the colon.

A) peritoneal cavity
B) urinary bladder
C) vaginal flora
D) renal vein

Question 17

Mechanisms used by the skin to prevent infection and protect the underlying tissue from invasion by potential pathogens include all the following, except

A) desquamation of the epithelium.
B) excretion of lysozyme by sweat glands.
C) antibiotics that inhibit many microorganisms.
D) mechanical separation of microorganisms from the tissues.

Question 18

The stomach can be considered a first line of defense against microbial infections because

A) most microorganisms are susceptible to the antibiotics and alkaline pH present in the stomach.
B) most microorganisms are killed by the liver enzymes that are emptied into the stomach during a meal.
C) the stomach produces proteases, which attack the lipopolysaccharide cell wall of the organisms.
D) most microorganisms are susceptible to the acid pH of the stomach.

Question 19

Factors that determine the pathogenicity and increase the virulence of organisms include all the following, except

A) an organism's ability to avoid phagocytosis.
B) an organism's ability to produce exotoxins and extracellular enzymes.
C) an organism's ability to produce infection when host conditions change.
D) an organism's ability to survive intracellularly when phagocytized.

Question 20

This bacterial state occurs when a host harbors a disease-causing organism, but does not show signs of disease.

A) Carrier
B) Transient
C) Resident
D) Indigenous

Question 21

This class of antibodies is usually found as a pentamer.

A) IgM
B) IgG
C) IgA
D) IgE

Question 22

Interferon is a substance produced by the body that inhibits viral replication. Interferon accomplishes this task by

A) digesting the virus that is attempting to attach to the host cell.
B) destroying the host cell before the virus can attach and replicate.
C) binding to surface receptors that stimulate the cell to synthesize enzymes that inhibit viral replication over several days.
D) stimulating platelets to produce $\beta$ -lysins.

Question 23

A subsequent exposure to the same antigen elicits a(n) _____, characterized by a rapid increase in IgG antibody associated with higher levels, a prolonged elevation, and a more gradual decline in antibody levels.

A) primary immune response
B) anamnestic immune response
C) opsonin immune response
D) innate immune response

Question 24

A physician notices that several patients are infected with Clostridium difficile, but only a few of the patients are symptomatic for disease. The reason for this discrepancy is

A) only those strains of the organism carrying the extrachromosomal DNA coding for the toxin gene will produce toxin and cause the individuals to be symptomatic.
B) only those strains of the organism carrying DNA coding for the toxin within its main DNA molecule will produce toxin and cause the individuals to be symptomatic.
C) the exotoxin produced contains only the nontoxic portion.
D) the exotoxin must be produced in conjunction with extracellular enzymes to cause problems.

Question 25

The effects of endotoxins consist of dramatic changes in all the following, except

A) blood pressure.
B) fluid imbalance.
C) clotting.
D) body temperature.

Question 26

These are low-molecular-weight proteins secreted by T cells.

A) Antibodies
B) Opsonins
C) Lymphokines
D) Lysozyme

Question 27

Immunity to intracellular bacterial pathogens, such as Mycobacterium tuberculosis, is primarily cell mediated, through the activities of

A) interferons and macrophages.
B) antibodies and lymphokines.
C) lysozyme, T lymphocytes, and antibodies.
D) T lymphocytes, lymphokines, and macrophages.

Question 28

A patient is brought to the emergency room with the following symptoms: body temperature of 102° F, low blood pressure, elevated WBC, and disseminated intravascular coagulation. This person has gram-negative rods growing in the blood. What is responsible for these symptoms?

A) Exotoxin
B) Extracellular enzymes
C) Endotoxin
D) Exfoliating toxin

Question 29

Pathogens can be transmitted through all the following routes, except

A) ingestion.
B) handwashing.
C) sexual contact.
D) air.

Question 30

Lysozyme is

A) an antibody produced by the skin.
B) a low-molecular-weight enzyme that hydrolyzes the peptidoglycan layer of bacterial cell walls.
C) an exotoxin that digests the lipopolysaccharide layer of the bacterial cell wall.
D) a radical similar to hydrogen peroxide.

Question 31

Healthy skin secretes these substances to help prevent colonization by transient and possibly pathogenic organisms.

A) Long-chain fatty acids
B) Sebaceous glands
C) Carbohydrates
D) Antibodies

Question 32

The resulting disease from this route of transmission is a disease of animals that is transmitted to humans.

A) Sexual contact
B) Zoonotic
C) Airborne
D) Ingestion

Question 33

Dissemination of a pathogen is

A) when a pathogen penetrates and grows in tissues.
B) when a pathogen multiplies intracellularly.
C) when a pathogen circumvents host antibodies by shifting key cell-surface antigens.
D) when infection with a pathogen spreads from the initial infection site to distant sites such as organs and tissues.

Question 34

Because infections can be encountered via the air, _____ can cause transmission of some pathogens.

A) cuts
B) eyes
C) coughing
D) eating

Question 35

Innate immunity consists of which of the following components?

A) Physical and chemical barriers such as the skin and mucous membranes
B) Blood proteins that act as mediators of infection
C) Cells capable of phagocytosis
D) All of the above are part of the innate immune system

Question 36

One of the most effective defenses bacteria have against phagocytosis is

A) enzymes.
B) the capsule.
C) plasmids.
D) lipopolysaccharide layer.

Question 37

The major constituents of the adaptive or specific immune response are

A) neutrophils.
B) macrophages.
C) monocytes.
D) lymphocytes.

Question 38

This process results in enhanced phagocytosis by neutrophils.

A) Opsonization
B) Chemotaxis
C) Digestion
D) Glycolysis

Question 39

All the following activities must occur for phagocytosis to take place and be effective in host defense, except

A) attachment of the particle to the phagocyte.
B) ingestion.
C) killing.
D) migration of lymphocytes to the area of infection (chemotaxis).