Q: Which equation best represents the clonal selection and expansion of lymphocytes after antigen challenge?

$N_{final} = N_{initial} \times 2^{n}$

Question 1

Which of the following best describes the role of the Major Histocompatibility Complex (MHC) in adaptive immunity?

Accepted Answer

MHC molecules are glycoproteins that play a vital role in recognition of self and presentation of foreign antigens to T cells.

Question 2

A patient receives a vaccine containing mRNA for the spike protein of SARS-CoV-2. What is the primary immune response expected from this vaccine?

Accepted Answer

The patient's cells will produce the spike protein, which will be recognized as foreign and stimulate both B and T cell responses.

Question 3

Which of the following is TRUE regarding the specificity of lymphocytes in adaptive immunity?

Accepted Answer

Each lymphocyte is specialized to react to only one specific antigen marker.

Question 4

What is the function of cytotoxic T cells (CD8+ T cells) in the immune response?

Accepted Answer

They destroy infected host cells by recognizing foreign peptides presented with MHC-I and inducing apoptosis.

Question 5

Which immunoglobulin class is most prevalent in the blood and provides long-term immunity?

Accepted Answer

IgG

Question 6

A molecule with a molecular weight of 1,500 is introduced into the body. What is its likely immunogenicity?

Accepted Answer

It is too small to be recognized as a foreign molecule and requires a carrier to be seen by the immune system.

Question 7

Which of the following statements about antigen-presenting cells (APCs) is correct?

Accepted Answer

APCs such as dendritic cells, macrophages, and B cells process and present antigens to T cells using MHC molecules.

Question 8

Which equation best represents the clonal selection and expansion of lymphocytes after antigen challenge?

Accepted Answer

$N_{final} = N_{initial} 	imes 2^{n}$

Question 9

Which of the following is a function of regulatory T cells?

Accepted Answer

They secrete anti-inflammatory cytokines to control the T-cell response and prevent autoimmunity.

Question 10

What is the primary difference between active and passive immunity?

Accepted Answer

Active immunity involves the production of memory cells and long-term protection, while passive immunity provides immediate but short-term protection without memory cell formation.

Question 11

Which of the following is NOT a requirement for an effective vaccine?

Accepted Answer

It should require numerous doses and boosters.

Question 12

Which type of vaccine was introduced during the COVID-19 pandemic and how does it work?

Accepted Answer

mRNA vaccine; delivers mRNA coding for the spike protein, which is produced by host cells and recognized by the immune system.

Question 13

Which of the following best explains why booster shots are sometimes necessary after initial vaccination?

Accepted Answer

Booster shots maintain long-term effectiveness by stimulating memory cells and increasing antibody concentration.

Question 14

Which of the following statements about immunoglobulin structure is correct?

Accepted Answer

Immunoglobulins consist of two heavy chains and two light chains connected by disulfide bonds.

Question 15

Which process describes the coating of pathogens with antibodies to enhance phagocytosis?

Accepted Answer

Opsonization

Question 16

Which of the following is a common misconception about vaccines?

Accepted Answer

Individuals can get the flu from the flu vaccine.

Question 17

Which cells are responsible for producing antibodies in response to antigen exposure?

Accepted Answer

Plasma cells derived from activated B cells

Question 18

Which of the following best describes the role of adjuvants in vaccines?

Accepted Answer

Adjuvants are compounds that enhance immunogenicity and prolong antigen retention at the injection site.

Question 19

Which of the following is TRUE regarding the function of memory cells in adaptive immunity?

Accepted Answer

Memory cells are responsible for rapid mobilization and a stronger response upon re-exposure to the same antigen.

Adaptive Immunity: The Third Line of Defense – Microbiology Study Notes

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