Question 1

Which of the following best describes the main difference between innate and adaptive immunity in vertebrates?

Accepted Answer

Innate immunity recognizes broad traits shared by pathogens, while adaptive immunity uses highly specific receptors for pathogen recognition.

Question 2

A patient receives a vaccine containing a harmless form of a virus. Upon later exposure to the actual virus, the patient mounts a much faster and stronger immune response. Which feature of adaptive immunity explains this phenomenon?

Accepted Answer

Immunological memory

Question 3

Which of the following statements about B cell antigen receptors is correct?

Accepted Answer

Each B cell antigen receptor has two identical antigen-binding sites formed by variable regions.

Question 4

Which process is responsible for generating the diversity of antigen receptors in B and T cells?

Accepted Answer

Random recombination of V, J, and C gene segments during lymphocyte development

Question 5

A T cell can only recognize an antigen when:

Accepted Answer

The antigen is presented on the surface of a host cell by an MHC molecule.

Question 6

Which of the following best explains why the immune system does not normally attack the body’s own cells?

Accepted Answer

Self-reactive lymphocytes are eliminated or inactivated during maturation.

Question 7

What is the role of plasma cells in the adaptive immune response?

Accepted Answer

They secrete antibodies specific to the antigen that activated their parent B cell.

Question 8

Which of the following is a direct result of clonal selection after a B cell binds its specific antigen?

Accepted Answer

The B cell divides to produce a clone of cells, some of which become plasma cells and others become memory cells.

Question 9

Which of the following best describes the structure of a T cell antigen receptor?

Accepted Answer

It consists of an alpha chain and a beta chain, each with variable and constant regions.

Question 10

A mutation prevents the formation of MHC molecules in a person. Which immune function would be most directly impaired?

Accepted Answer

Presentation of antigen fragments to T cells

Question 11

If a person is exposed to antigen A on day 0 and then to both antigen A and antigen B on day 28, which of the following best describes the antibody response, according to the graph provided?

Accepted Answer

Antibody concentration to antigen A will be much higher and peak faster after the second exposure compared to the first.

Question 12

Which of the following is true regarding the specificity of antigen receptors on B and T cells?

Accepted Answer

All antigen receptors on a single B or T cell are identical and bind the same epitope.

Question 13

Which of the following best explains why a person who has recovered from chicken pox is unlikely to get the disease again?

Accepted Answer

Long-lived memory cells specific for the chicken pox virus enable a rapid and strong secondary immune response.

Question 14

Which of the following is a correct sequence of events in the development of a functional B cell antigen receptor?

Accepted Answer

Random recombination of V and J segments, transcription, RNA processing, translation, assembly of light and heavy chains

Question 15

Which of the following is a real-world example of the importance of self-tolerance in adaptive immunity?

Accepted Answer

A person develops an autoimmune disease such as type 1 diabetes, where the immune system attacks insulin-producing cells.

Question 16

Which of the following best describes the relationship between an epitope and an antigen?

Accepted Answer

An epitope is a specific part of an antigen that is recognized and bound by an antigen receptor.

Question 17

Which of the following equations correctly represents the number of possible combinations for a light chain given 40 V segments, 5 J segments, and 1 C segment?

Accepted Answer

$$40 	imes 5 	imes 1$$

Question 18

Which of the following best explains why the adaptive immune response is slower than the innate immune response upon first exposure to a pathogen?

Accepted Answer

Adaptive immunity requires the production and selection of specific lymphocytes that recognize the pathogen.

Adaptive Immunity: Pathogen-Specific Recognition and the Role of Lymphocyte Receptors

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