What is the mechanism that skin uses to protect against diseases caused by organisms?
high pH
mucus
tears
desiccation
2.
(credit: modification of work by Lambert, R./Journal of Applied Microbiology)
This image shows the growth rate of some types of bacteria in different pH values.
Based on this image, and keeping in mind the skin forms a barrier against many types of bacteria, make a claim about the likely values for skin's pH.
A neutral pH of 7.0.
Around 6.5.
Between 5.5 and 7.5.
More than 7.5 or less than 5.5.
3.
Which of the following produces an immediate innate immune response by recognizing an invading pathogen and engulfing it?
macrophage
cytokine
inflammation
antibody
4.
How does inflammation develop?
Inflammation is induced by molecules such as cytokines and histamine that are produced by various host cells in response to pathogens at the site of injury or infection.
During inflammation, all blood cells retreat from the site of infection in order to protect the circulatory system from pathogen infection.
Inflammation is an ongoing condition in the human body, part of the way that the innate immune system can respond immediately to an infection.
When an infection occurs, an immediate inflammatory response occurs as soon as pathogens enter the body.
5.
Which innate immune system component uses major histocompatibility class (MHC) I molecules directly in its defense strategy?
macrophages
neutrophils
natural killer cells
interferon
6.
What is the difference between natural killer cells and macrophages?
Natural killer cells are not always present in the body and must be induced, whereas macrophages are constantly present.
Natural killer cells actually kill foreign cells, whereas macrophages serve only a signaling function.
Only macrophages can invade host tissues to fight foreign cells that make their way into those tissues.
Natural killer cells kill foreign cells through the processes of lysis and proteolysis, whereas macrophages kill foreign cells by phagocytosis.
7.
What is the composition of major histocompatibility class (MHC) I molecules?
lipids
nucleic acids
carbohydrates
proteins
8.
What is the function of major histocompatibility class (MHC) I molecules?
MHC I molecules assist with strengthening the cell membrane.
MHC I molecules present antigens on the surface of a cell.
MHC I molecules allow movement of materials across the cell membrane.
MHC I molecules provide signals for processes involved in cell division.
9.
What is the complement system?
The complement system contains macrophages that phagocytize foreign pathogens.
The complement system monitors MHC I molecules on cells and destroys any cell that displays an antigen belonging to a pathogen.
The complement system contains a group of about 20 proteins in the blood that attack pathogens in a cascading fashion to mark and destroy them.
The complement system is made up of antibodies specific to each pathogen that are synthesized when a pathogen enters the body.
10.
Which of the following occurs more rapidly as the result of activation of the complement system?
pathogen invasion
pathogen detection
pathogen reproduction
pathogen engulfment
11.
What is another term for adaptive immunity?
acquired immunity
innate immunity
passive immunity
humoral immunity
12.
How does adaptive immunity work?
A person is born having a specific immune responses against any pathogen that the body is exposed to.
A person is born with the ability to develop a specific immune response against any pathogen within minutes of being exposed to that pathogen.
A person does not have any immune response against a pathogen, but develops a temporary specific response to that pathogen that is then forgotten.
A person does not have specific immune response against a pathogen, but develops a specific response to that pathogen that is rapidly recalled later if infection by the same pathogen occurs again.
13.
What component of the innate immune system is not part of the adaptive immune system?
T cells
antibodies
mast cells
B cells
14.
What is the difference between innate and adaptive immune responses?
The adaptive immune system is faster-acting than the innate immune system.
The adaptive immune system produces a longer-lasting defense than the innate immune system.
The innate immune system produces a more specific defense than the adaptive immune system.
The innate immune system has a more sophisticated memory than the adaptive immune system.
15.
Which cells are unique to the humoral immune response?
cytotoxic T cells
antigen-presenting cells
helper T cells
B cells
16.
(credit: modification of work by Reh0318/Wikipedia, CC BY-SA 4.0)
This image shows how the humoral immune system works.
What is happening at step 2?
A B cell is preparing to release antibodies.
A B cell is engulfing the antigens.
A B cell is displaying the antigens of the pathogen.
A B cell is getting ready to divide.
17.
An antibody sometimes binds to an antigen other than the antigen that elicited its synthesis. What term refers to this behavior?
avidity
cross reactivity
hypersensitivity
affinity
18.
A biologist runs some tests and observes that the same antibody binds to several different proteins. Why might this occur?
The antibody is showing that it has high affinity for antigens.
The antibody is showing that it has high avidity for antigens.
The antibody is showing cross reactivity to the antigens.
The antibody is showing hypersensitivity to the antigens.
19.
How many and what types of polypeptides make up an antibody molecule?
one heavy polypeptide chain and one light polypeptide chain
two heavy polypeptide chains and one light polypeptide chain
two heavy polypeptide chains and two light polypeptide chains
one heavy polypeptide chain and two light polypeptide chains
20.
Why do antibodies isolated from the same individual show a variety of constant domains?
The antibodies were synthesized in response to infections by different pathogens.
The antibodies were transmitted as the result of passive immunity.
The antibodies have different specificities of antigen binding.
The antibodies belong to different classes of immunoglobulin molecules.
21.
What enzyme is responsible for the random excision of variable gene segments making up an antibody light chain in DNA?
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