Question 1

The specific regions within the variable region of an antibody that are responsible for antibody diversity and antigen specificity are called __________ regions.

Accepted Answer

The answer of The specific regions within the variable region...

Question 2

The class of immunoglobulin transferred from mother to infant during breast-feeding is

Accepted Answer

IgA is the class of immunoglobulin that is predominantly found in breast milk and is transferred from the mother to the infant during breastfeeding. This immunoglobulin plays a crucial role in protecting the infant's gastrointestinal and respiratory tract from infections. IgG can also be transferred from the mother to the fetus during pregnancy.

Question 3

A type of antibody light chain is the ___________ chain.

Accepted Answer

There are two types of antibody light chains, kappa and lambda. Omega, delta, and alpha are not types of antibody light chains.

Question 4

Which of the following is a characteristic associated with secondary antibody responses?

Accepted Answer

Secondary antibody responses have a shorter lag phase, higher antibody titer, and higher antibody affinity compared to primary antibody responses. Therefore, all of the choices (A, B, and C) are characteristics associated with secondary antibody responses.

Question 5

Which of the following is not a function of the Fc portion of the immunoglobulin molecule?

Accepted Answer

The Fc portion of the immunoglobulin molecule is responsible for binding to host cells and phagocytic cells (A), as well as binding to components of the complement system (B). However, the Fc portion does not bind to the antigen (C), as that is the function of the variable regions of the immunoglobulin molecule. Therefore, option D ("all of the choices") is also incorrect.

Question 6

The secondary immune response is typically stronger than the primary response because __________ during the secondary response.

Accepted Answer

During a primary immune response, a small number of B and T cells specific to the antigen are activated, and it takes time for them to undergo clonal expansion and differentiate into effector cells. However, during the secondary response, a larger number of memory cells that already recognize the antigen are present, allowing for a more rapid and robust immune response. Therefore, option D is correct as it explains that a larger population of lymphocytes reactive to antigen has developed during the secondary immune response.

Question 7

Which of the following types of immunoglobulins is most abundant in serum?

Accepted Answer

IgG is the most abundant immunoglobulin in the serum, comprising approximately 75% of all immunoglobulins present.

Question 8

Which of the following prevents some bacteria from adhering to mucosal surfaces?

Accepted Answer

IgA is mainly found in mucosal secretions such as tears, saliva, colostrum, bronchial and intestinal secretions, and prevents bacterial adherence to these surfaces. IgD, IgM, and IgE do not have a significant role in preventing bacterial adherence to mucosal surfaces.

Question 9

Matching
1) log phase
2) decline phase
3) plateau phase
4) lag phase
A. This phase directly follows a primary challenge with an antigen.
B. The antibody titer stabilizes.
C. The antibody titer rises quickly.
D. Antibodies are naturally metabolized.

Accepted Answer

The answer of Matching
1) log phase
2) decline phase
3) plateau phase
4)...

Question 10

The only immunoglobulin class with members able to cross the placental barrier is

Accepted Answer

IgG is the only immunoglobulin class that can cross the placental barrier and provide passive immunity to the fetus. IgA is found in bodily secretions, IgM is the primary immunoglobulin produced in response to an initial infection, and IgE is involved in allergic reactions.

Question 11

The protein chains in a complete antibody molecule are connected to each other by ___________ bonds.

Accepted Answer

The protein chains in a complete antibody molecule contain disulfide bonds that hold the structure together. These covalent bonds form between two cysteine residues on separate chains, resulting in a strong and stable connection between the protein chains.

Question 12

If the clonal selection theory is correct, there exists at least one lymphocyte capable of synthesizing an antibody specific to each antigen prior to exposure to the antigen.

Accepted Answer

The clonal selection theory proposes that there is a diverse population of lymphocytes in the body, each capable of producing a unique antibody specific to a particular antigen. This diversity is generated through gene rearrangement and somatic hypermutation before exposure to the antigen. Therefore, there should be at least one lymphocyte capable of synthesizing an antibody specific to each antigen before exposure.

Question 13

Matching
1) IgG
2) IgD
3) IgM
4) IgA
A. accounts for about 10% of the immunoglobulin pool
B. the major immunoglobulin in human serum
C. has special features associated with secretory mucosal surfaces
D. found in trace amounts in the serum

Accepted Answer

The answer of Matching
1) IgG
2) IgD
3) IgM
4) IgA
A. accounts for...

Question 14

In an antibody molecule, each loop of approximately 60 amino acids is called a __________.

Accepted Answer

The answer of In an antibody molecule, each loop of...

Question 15

Which enzyme inserts nucleotides at the V-J junction to add further diversity?

Accepted Answer

Terminal deoxynucleotidyl transferase is responsible for inserting random nucleotides at the V-J junctions during somatic recombination of the variable (V), diversity (D), and joining (J) gene segments in developing lymphocytes, thereby adding further diversity to the B and T cell receptor repertoire. DNA polymerase primarily functions in DNA replication and repair, while RAG enzymes and reverse transcriptase are involved in the recombination process but are not responsible for nucleotide insertion at the V-J junctions.

Question 16

The changeover in production from IgM to IgG by an activated B cell is called a __________ __________ event.

Accepted Answer

The answer of The changeover in production from IgM to...

Question 17

The __________ chains are structurally distinct for each immunoglobulin class.

Accepted Answer

The answer of The __________ chains are structurally distinct for...

Question 18

Which of the following function(s) as the B cell antigen receptor?

Accepted Answer

The B cell antigen receptor is made up of membrane-bound immunoglobulin, and in its monomeric form, IgM serves as the primary antigen receptor on the surface of naive B cells. IgG, IgE, and IgA are secreted forms of immunoglobulin and do not function as B cell receptors.

Question 19

Pentameric IgM activates complement up to 20-fold more effectively than does the hexameric form of IgM.

Accepted Answer

Pentameric IgM is the form that effectively activates complement, not a hexameric form. IgM naturally exists as a pentamer when it is secreted by plasma cells, and this pentameric form is particularly efficient at activating the complement system due to its multivalent binding capability, which allows for efficient cross-linking of antigens. There is no naturally occurring hexameric form of IgM involved in complement activation.

Question 20

In an antibody molecule, the __________ region mediates binding to host cells.

Accepted Answer

The answer of In an antibody molecule, the __________ region...

Quiz 33: Specific Adaptive Immunity