Q: Which equation correctly represents the relationship between the number of antigen-binding sites and the valence of an antibody?

$$\text{Valence} = \text{Number of antigen-binding sites}$$

Question 1

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

Accepted Answer

Innate immunity provides immediate defense against any pathogen, while adaptive immunity develops resistance to a specific pathogen over time.

Question 2

Which immunoglobulin class is most abundant in serum and is responsible for enhancing phagocytosis, neutralizing toxins and viruses, and protecting fetuses and newborns?

Accepted Answer

IgG

Question 3

A patient receives an injection of antibodies after exposure to rabies. What type of immunity is this?

Accepted Answer

Artificially acquired passive immunity

Question 4

Which of the following statements about haptens is correct?

Accepted Answer

Haptens are small molecules that must combine with carrier molecules to become antigenic.

Question 5

Which immunoglobulin is primarily found in secretions such as saliva and mucus, and provides mucosal protection?

Accepted Answer

IgA

Question 6

A newborn is protected from infection by antibodies received through colostrum. This is an example of:

Accepted Answer

Naturally acquired passive immunity

Question 7

Which of the following is a function of cytotoxic T lymphocytes (CTLs)?

Accepted Answer

Destroy target cells by releasing perforin and granzymes

Question 8

Which process involves antibodies binding to antigens and causing the clumping of pathogens?

Accepted Answer

Agglutination

Question 9

What is the role of MHC Class II molecules in the immune response?

Accepted Answer

They are present on antigen-presenting cells and present antigens to helper T cells.

Question 10

Which cell type is responsible for killing virus-infected cells that do not express MHC I correctly?

Accepted Answer

Natural killer (NK) cells

Question 11

A patient is exposed to a pathogen for the first time. Which type of antibody is produced first in response to the infection?

Accepted Answer

IgM

Question 12

Which of the following best describes the function of regulatory T cells (Treg cells)?

Accepted Answer

They suppress T cells against self to prevent autoimmune reactions.

Question 13

Which of the following is NOT a function of antibodies?

Accepted Answer

Directly killing bacteria by lysis

Question 14

Which equation correctly represents the relationship between the number of antigen-binding sites and the valence of an antibody?

Accepted Answer

$$	ext{Valence} = 	ext{Number of antigen-binding sites}$$

Question 15

Which of the following best explains why secondary immune responses are faster and stronger than primary responses?

Accepted Answer

Memory cells are produced during the primary response and respond rapidly upon re-exposure.

Question 16

Which of the following is the correct sequence of events in T-dependent antigen activation of B cells?

Accepted Answer

B cell recognizes antigen, presents it to helper T cell, helper T cell activates B cell, B cell differentiates into plasma cells.

Question 17

Which immunoglobulin class is associated with allergic reactions and defense against parasitic worms?

Accepted Answer

IgE

Question 18

Which of the following best describes the role of cytokines in the immune system?

Accepted Answer

Cytokines are chemical messengers that communicate between immune cells.

Question 19

Which of the following is the correct definition of serology?

Accepted Answer

The study of reactions between antibodies and antigens.

Question 20

A laboratory test detects the presence of IgM antibodies in a patient's serum. What does this most likely indicate?

Accepted Answer

The patient is experiencing a primary immune response to a recent infection.

Immunity and Immune Responses: Key Concepts in Microbiology

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