Chapter 16 (Unit 4 Exam)

Question 1

The four stages of an adaptive immune response include ________, ________, ________, and ________.

Answer 1

Recognition, Activation, Response, Memory

Explanation: An adaptive immune response proceeds through stages of recognizing the antigen, activating immune cells, responding to the infection, and creating a memory for a quicker response upon re-exposure.

Question 2

During the development of B and T cells, B cells mature in the __________, while T cells mature in the __________.

Answer 2

bone marrow, thymus

Explanation: B cells undergo maturation in the bone marrow where they develop immunoglobulins as surface receptors, whereas T cells mature in the thymus where they acquire T-cell receptors before migrating to lymphoid tissues.

Question 3

An antibody binding an antigen can lead to which of the following end results?

Options:
A) Neutralization of the antigen, opsonization, complement activation, and immobilization of bacteria
B) Direct destruction of the pathogen’s DNA, alteration of the host’s immune response, and the production of mucus
C) Inhibition of phagocyte migration, suppression of cytokine release, and enhancement of pathogen growth
D) All of the above

Answer 3

A) Neutralization of the antigen, opsonization, complement activation, and immobilization of bacteria

Explanation: The binding of an antibody to an antigen can neutralize the antigen, make it easier for phagocytes to engulf by opsonization, activate the complement system which leads to the lysis of the pathogen, and immobilize bacteria preventing their spread.

Question 4

The third line of adaptive immunity is acquired ____________ immunity that occurs after an immunizing event such as an infection or vaccination.

Answer 4

Specific

Explanation: The third line of adaptive immunity is specific and is a product of B and T lymphocytes, which undergo a selective process specializing them for reacting to only one specific antigen .

Question 5

IgM antibodies are the first to be produced in response to an infection and are mainly found in the __________.

Answer 5

blood

Explanation: IgM is the largest antibody and is the first to increase in the immune response to an antigen. It is primarily found in the blood and is effective at forming complexes with antigens and activating the complement system.

Question 6

During B-cell activation, the types of B cells produced include only plasma cells.

A) True
B) False

Answer 6

B) False

Explanation: B-cell activation leads to the production of both plasma cells, which secrete antibodies, and memory B cells, which provide long-term immunity.

Question 7

What is the role of the major histocompatibility complex (MHC) in the immune system?

Options:
A) To produce antibodies against pathogens.
B) To act as physical barriers against infections.
C) To code for cell markers essential for immune system recognition of self.
D) To directly kill infected cells and pathogens.

Answer 7

C) To code for cell markers essential for immune system recognition of self.

Explanation: The MHC is a set of genes that code for markers on the surfaces of cells. These markers are essential for the immune system to distinguish self from non-self.

Question 8

The role of cytotoxic T cells in apoptosis includes targeting __________ such as virally infected cells, tumor cells, and cells with intracellular bacteria or parasites.

Answer 8

abnormal or infected cells

Explanation: Cytotoxic T cells induce apoptosis in cells that are abnormal or infected with pathogens. They are critical for the immune response to virally infected cells, cancer cells, and cells with intracellular pathogens.

Question 9

Immune system markers function in attaching to self-antigens and aid in cellular development.

A) True
B) False

Answer 9

B) False

Explanation: Immune system markers attach to non-self or foreign antigens, not self-antigens. They bind to cell surface receptors indicating “self,” transmit chemical messages to coordinate the immune response, and aid in cellular development.

Question 10

Which of the following is NOT a characteristic of adaptive specific immunity?

A) Specificity
B) Memory
C) Diversity
D) Inducibility
E) Clonality

Answer 10

E) Clonality

Explanation: Adaptive specific immunity is characterized by its specificity for a particular antigen, the memory of past pathogens, and the diversity of lymphocytes to respond to any antigen. Clonality is not listed as a characteristic of adaptive immunity in the provided material.

Question 11

What is the primary function of IgD antibodies?

Options:
A) To trigger the body’s immune response to parasites.
B) To neutralize bacterial toxins.
C) To signal the B cells to be activated.
D) To cross the placenta and provide immunity to the fetus.

Answer 11

C) To signal the B cells to be activated.

Explanation: IgD is found in small amounts in the blood, but is primarily located on the surface of B cells as a receptor. Its main function is believed to be the regulation of B-cell mediated immune responses.

Question 12

IgE is involved in defense against parasitic infections and is also responsible for the symptoms of __________.

Answer 12

allergies

Explanation: IgE binds to allergens and triggers histamine release from mast cells and basophils, and is also associated with immunity to parasites like worms. This class of antibody is mainly responsible for the symptoms of allergic reactions, such as hay fever, asthma, and anaphylaxis.

Question 13

The immune system responds to superantigens in a controlled manner, similar to how it responds to regular antigens.

A) True
B) False

Answer 13

B) False

Explanation: Superantigens are a class of antigens that cause non-specific activation of T-cells resulting in polyclonal T cell activation and massive cytokine release, which is not a controlled response.

Question 14

The process of T-cell activation involves recognition of antigens presented by MHC molecules, followed by __________ and differentiation into various types of T cells.

Answer 14

clonal expansion

Explanation: T-cell activation is initiated by the recognition of antigens presented by MHC molecules on APCs. This triggers clonal expansion, where T cells proliferate and differentiate into effector cells and memory T cells.

Question 15

T cells require the presence of specific markers or antigens to be activated, but B cells do not require antigen presentation with MHC to be activated.

A) True
B) False

Answer 15

A) True

Explanation: T cells indeed require antigen presentation alongside MHC molecules for activation. In contrast, most B cells can be activated without the need for antigens to be presented with MHC, though some B cells do require T cell help for activation.

Question 16

In a graph illustrating the secondary immune response, the antibody level peaks later and lower than in the primary immune response.

A) True
B) False

Answer 16

B) False

Explanation: In a secondary immune response, the level of antibodies rises more quickly and to a higher level compared to the primary response due to the action of memory cells formed during the primary response.

Question 17

IgA antibodies are most commonly associated with allergic reactions and protection against parasitic infections.

A) True
B) False

Answer 17

B) False

Explanation: IgA is found in mucous secretions and is important in local immunity on mucosal surfaces. It is not typically associated with allergic reactions; that role belongs to IgE, which is involved in allergic reactions and protection against parasitic infections.

Question 18

Which types of cells can act as antigen-presenting cells?

Options:
A) Neutrophils, basophils, and eosinophils
B) Erythrocytes, platelets, and fibroblasts
C) Dendritic cells, macrophages, and B cells
D) Epithelial cells, endothelial cells, and adipocytes

Answer 18

C) Dendritic cells, macrophages, and B cells

Explanation: Antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells are specialized to take up antigens, process them, and present them on their surface to T cells along with MHC molecules.

Question 19

How is the third line of defense different from the first and second lines of host defense mechanisms?

Options:
A) It is non-specific and does not provide long-lasting immunity.
B) It consists only of physical barriers like skin and mucous membranes.
C) It is specific, has memory, and is adaptive, improving upon repeated exposure to a pathogen.
D) It acts immediately upon infection and does not change with repeated exposure.

Answer 19

C) It is specific, has memory, and is adaptive, improving upon repeated exposure to a pathogen.

Explanation: The third line of defense is the adaptive immune system, which is highly specific to the pathogen it targets. It has the ability to remember past infections and respond more effectively upon subsequent exposures.

Question 20

List several types of vaccines and their current utilization. Which of the following is not a type of vaccine used today?

Options:
A) Live attenuated vaccines
B) Inactivated vaccines
C) Subunit vaccines
D) Magnetic vaccines

Answer 20

D) Magnetic vaccines

Explanation: Common types of vaccines include live attenuated vaccines, which use a weakened form of the germ; inactivated vaccines, which use a killed version; and subunit vaccines, which include parts of the germ like its protein. Magnetic vaccines are not a recognized type of vaccine in immunology.

Question 21

Characteristics of antigens that optimize their immunogenicity include being foreign to the host, having high molecular weight, and being __________.

Answer 21

complex and stable

Explanation: The immunogenicity of an antigen is determined by several factors, including being foreign to the host’s immune system, having a large molecular weight, and possessing a complex, stable structure that the immune system can recognize and respond to.

Question 22

An effective vaccine should be safe, provide long-lasting protection, be able to elicit a protective immune response, and be __________.

Answer 22

cost-effective

Explanation: The qualities of an effective vaccine include safety, immunogenicity (elicits the desired immune response), duration of protection (long-lasting), and being cost-effective to produce and distribute.

Question 23

How do the terms antigen, immunogen, and epitope differ?

Options:
A) Antigens and immunogens are substances that elicit an immune response; epitopes are the part of antigens that interact with antibodies.
B) Antigens are the only substances that can trigger an immune response, while immunogens and epitopes cannot.
C) Immunogens are cells that produce antibodies, antigens cause disease, and epitopes are medications that enhance immunity.
D) Epitopes are cells that present antigens, and immunogens are the sites where antibodies bind.

Answer 23

A) Antigens and immunogens are substances that elicit an immune response; epitopes are the part of antigens that interact with antibodies.

Explanation: Antigens are substances that can be bound by an antibody or an antigen receptor on B and T cells, whereas immunogens are antigens that can elicit an immune response. An epitope is the specific part of the antigen that is recognized and bound by an antibody.

Question 24

The process of antigen recognition is different in T cells and B cells because T cells recognize antigens with the help of ________ molecules, while B cells can recognize antigens directly with their ________ receptors.

Answer 24

MHC, B-cell

Explanation: T cells require antigens to be presented with MHC molecules to recognize them, whereas B cells have B-cell receptors that can directly bind to antigens without MHC presentation.

Question 25

A secondary immune response is typically slower and less effective than a primary immune response.

A) True
B) False

Answer 25

B) False

Explanation: A secondary immune response is faster and more effective than a primary immune response due to the presence of memory cells that were generated during the first exposure to the antigen.

Question 26

What are the main functions of the major T-cell types and their subsets?

Options:
A) Helper T cells assist in antibody production; cytotoxic T cells kill infected cells; regulatory T cells suppress immune responses.
B) Helper T cells kill pathogens directly; cytotoxic T cells produce antibodies; regulatory T cells activate other immune cells.
C) All T-cell types and their subsets are involved in the production of antibodies.
D) Helper T cells produce mucus; cytotoxic T cells initiate inflammation; regulatory T cells induce fever.

Answer 26

A) Helper T cells assist in antibody production; cytotoxic T cells kill infected cells; regulatory T cells suppress immune responses.

Explanation: Helper T cells (CD4+) assist in the immune response, including aiding B cells to produce antibodies. Cytotoxic T cells (CD8+) directly kill cells infected by viruses and other pathogens. Regulatory T cells (Tregs) help to modulate and suppress immune responses to maintain homeostasis and prevent autoimmunity.

Question 27

What is the structure of a B-cell receptor composed of?

Options:
A) A single heavy chain and two light chains.
B) Two heavy chains and two light chains, forming a Y-shaped molecule.
C) A single light chain and a T-cell receptor complex.
D) Multiple antigen-binding sites without heavy or light chains.

Answer 27

B) Two heavy chains and two light chains, forming a Y-shaped molecule.

Explanation: A B-cell receptor is composed of two identical heavy chains and two identical light chains, linked to form a Y-shaped molecule that can bind to specific antigens.

Question 28

Which immunoglobulin is the most abundant in the blood and extracellular fluid, and is the only one capable of crossing the placenta?

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

Answer 28

C) IgG

Explanation: IgG is the most abundant type of antibody in circulation, representing around 75-80% of serum antibodies. It plays a crucial role in the body’s immune response by neutralizing toxins and is the only antibody that can cross the placenta to give passive immunity to the fetus.

Question 29

The major histocompatibility complex (MHC) is a set of genes that code for markers found on all cells except red blood cells.

A) True
B) False

Answer 29

A) True

Explanation: The MHC genes give rise to MHC glycoprotein receptors which play a vital role in the immune system’s recognition of self and the rejection of foreign tissues.

Question 30

Upon binding an antigen, an antibody can lead to which of the following outcomes?

Options:
A) Neutralization, opsonization, and agglutination
B) Immediate destruction of the antibody
C) Release of histamines and other allergic mediators
D) Suppression of the immune response

Answer 30

A) Neutralization, opsonization, and agglutination

Explanation: Antibodies binding to antigens can neutralize pathogens or toxins, opsonize pathogens for phagocytosis, and cause agglutination, which clumps antigens together, making them easier to be phagocytized.

Question 31

Summarize the maturation process of B cells and T cells.

Options:
A) Both mature in the thymus and circulate in the blood.
B) Both originate and mature in the bone marrow.
C) B cells mature in the bone marrow, while T cells mature in the thymus.
D) B cells mature in the thymus, while T cells mature in the spleen.

Answer 31

C) B cells mature in the bone marrow, while T cells mature in the thymus.

Explanation: B cells undergo maturation in the bone marrow and T cells migrate to the thymus to complete their maturation process before moving to lymphoid tissues.

Question 32

The five types of antibodies include IgG, IgM, IgA, IgD, and ________. Each has distinct characteristics such as location or specific function in the immune response.

Answer 32

IgE

Explanation: Each type of antibody has a unique role: IgG is the most abundant in serum, IgM is the first to respond to an infection, IgA is found in mucous membranes, IgD is involved in the activation of B cells, and IgE plays a key role in allergic reactions.

Question 33

Lymphocytes are capable of responding to nearly any antigen imaginable due to the process of clonal deletion.

A) True
B) False

Answer 33

B) False

Explanation: The ability of lymphocytes to respond to nearly any antigen is due to their diversity, which is achieved through processes like clonal selection and the rearrangement of gene segments that encode for antigen receptors. Clonal deletion is a process that eliminates self-reactive lymphocytes to prevent autoimmunity.

Question 34

What are the four stages of an adaptive immune response?

A) Recognition, Reaction, Remembrance, Regulation
B) Recognition, Response, Remembrance, Recovery
C) Recognition, Response, Recovery, Regulation
D) Recognition, Reaction, Recovery, Remembrance

Answer 34

B) Recognition, Response, Remembrance, Recovery

Explanation: The four stages of an adaptive immune response include the recognition of the pathogen, the response to the attack, the development of memory cells to remember the pathogen, and recovery or the elimination of the pathogen .

Question 35

The five types of antibodies are IgG, IgM, IgA, IgD, and ________, each having unique functions and locations in the body.

Answer 35

IgE

Explanation: IgG is involved in long-term immunity and can cross the placenta; IgM is the first responder to an infection; IgA is found in mucous membranes; IgD acts as a B cell receptor; and IgE is associated with allergic responses and protection against parasites.

Question 36

What are the four categories of acquired immunity?

Options:
A) Naturally acquired active, naturally acquired passive, artificially acquired active, artificially acquired passive
B) Innate, adaptive, passive, and active
C) Cellular, humoral, active, and passive
D) Primary, secondary, tertiary, and quaternary

Answer 36

A) Naturally acquired active, naturally acquired passive, artificially acquired active, artificially acquired passive

Explanation: Acquired immunity is classified based on how the immunity is acquired: naturally acquired active immunity occurs through natural infection; naturally acquired passive immunity is from mother to infant; artificially acquired active immunity is through vaccination; and artificially acquired passive immunity is through antibodies from another source.