Microbiology Exam IV

Innate immunity includes all of the following except

production of antibody

Normal microbiota provide protection from infection in each of the following ways EXCEPT

they produce lysozyme

Macrophages arise from

monocytes

Which of the following exhibits the highest phagocytic activity?

macrophages

All of the following are effects of histamine EXCEPT

fever

What defense mechanism participates in elimatating contaminating microbes when you get a deep cut?

phagocytosis in the inflammatory response

All of the following pertain to fever EXCEPT that it

accelerates microbial growth by increasing iron absorption from the digestive tract

Each of the following is an effect of complement activation EXCEPT

interference with viral replication

The ID₅₀ is

the dose that will cause an infection in 50 percent of the test population

Most pathogens that gain access through the skin

enter through hair follicles and sweat ducts

The most frequently used portal of entry for pathogens is the

mucous membranes of the respiratory tract

Which is NOT specifically employed by pathogens to avoid destruction by phagocytosis?

producing superantigens

The best description of direct damage by a pathogen is

host cells destroyed when pathogens metabolize and multiply

All of the following bacteria release endotoxin EXCEPT

clostridium botulinum (gram-positive)

What is a likely cause of food intoxication?

staphylococcal enterotoxin

Lysogenic bacteriophages contribute to bacterial virulence because bacteriophages

give new gene sequences to the host bacteria

All of the following organisms produce exotoxins EXCEPT

salmonella typhi (gram-negative)

Botulism is caused by ingestion of a proteinaceous exotoxin; therefore, it can easily be prevented by

boiling food prior to consumption

Endotoxins are

part of the gram-negative cell wall

The presence of which of the following indicates a current infection rather than a previous infection or vaccination?

IgM

Which areas represent antigen-binding sites?

a and b

Which of the following is the best definition of antigen?

a chemical that elicits an antibody response and can combine with these antibodies

The most abundant class of antibodies in serum is

IgG

Large antibodies that agglutinate (clump) antigens are

IgM

In addition to IgG, the antibodies that can fix complement are

IgM

The antibodies found almost entirely and only on the surface of B cells (not secreted from them), and which always exist as monomers, are

IgD

The antibodies found in mucus, saliva, and tears are

IgA

Which of the following is the best definition of epitope?

specific regions on antigens that interact with antibodies

Plasma cells are activated by a

antigen

When an antibody binds to a toxin, the resulting action is refered to as

neutralization

Which of the following destroys virus-infected cells?

CTL (cytotoxic T lymphocyte)

Which of the following is NOT a characteristic of cellular immunity?

B cells make antibodies

What type of immunity results from recovery from mumps?

naturally acquired active immunity

Desensitization involves injection of

antigens

Which of the following is NOT an example of hypersensitivity?

transplant rejections

Anaphylaxis is the term for reactions caused when certain antigens combine with

IgE antibodies

Hemolytic disease of the newborn can result from an

Rh^- mother with an Rh⁺ fetus

Which of the following is NOT true about type I reactions?

they involve helper T cells

The chemical mediators of anaphylaxis are

found in basophils and mast cells