Nokea
What is included in the humoral immune response?
- A. Surveillance for malignant cell changes
- B. Production of antigen-specific immunoglobulins
- C. Direct attack of antigens by activated B lymphocytes
- D. Releasing cytokines responsible for destruction of antigens
Correct Answer: B
Rationale: The humoral immune response involves the production of antigen-specific antibodies (immunoglobulins) by B cells, which neutralize pathogens.
You may also like to solve these questions
What is NOT true about Shigella?
- A. Causes a form of bloody diarrhea
- B. It is a motile species possessing a flagellum
- C. It exploits specialized intestinal cells, called M cells, to infect the host
- D. It can travel from cell to cell, propelled by actin comets
Correct Answer: B
Rationale: The correct answer is B because Shigella is a non-motile species and does not possess a flagellum. Shigella relies on non-flagellar mechanisms for its movement within host cells. Choice A is true as Shigella causes bloody diarrhea. Choice C is also true as Shigella exploits M cells to infect the host. Choice D is true as Shigella can move from cell to cell using actin comets. In summary, choice B is incorrect because Shigella does not have a flagellum, while choices A, C, and D are all true characteristics of Shigella.
What was the important contribution to microbiology of Anton Van Leeuwenhoek in the 1600s?
- A. He was the first to observe microorganisms
- B. He disproved the theory of spontaneous generation of microorganisms
- C. He was the first to show that a disease could be caused by a microorganism
- D. He was the first to describe the process of fermentation
Correct Answer: A
Rationale: The correct answer is A: He was the first to observe microorganisms. Van Leeuwenhoek's important contribution to microbiology was his discovery of microorganisms using his own handcrafted microscopes. This observation revolutionized the field by providing the first direct evidence of the existence of microorganisms.
Choice B is incorrect because Leeuwenhoek's observations actually supported the idea of spontaneous generation. Choice C is incorrect because he did not link microorganisms to diseases. Choice D is incorrect because the process of fermentation was described by others before Leeuwenhoek.
When a B-cell undergoes immunoglobulin class switching
- A. the variable region of the light chain changes, but its constant region remains the same
- B. the variable region of the light chain remains the same, but its constant region changes
- C. the variable region of the heavy chain remains the same but its constant region changes
- D. the variable region of the heavy chain changes but its constant region remains the same
Correct Answer: C
Rationale: When a B-cell undergoes immunoglobulin class switching, the variable region of the heavy chain remains the same but its constant region changes. This process allows the B-cell to produce antibodies with different effector functions while maintaining the same antigen specificity. By changing the constant region of the heavy chain, the B-cell can switch from producing IgM to IgG, IgA, or IgE antibodies. Choices A, B, and D are incorrect because they do not accurately describe the specific changes that occur during immunoglobulin class switching in B-cells.
Select the correct statement during an allergic reaction.
- A. An allergen binds with IgE antibodies.
- B. The mast cells are deactivated.
- C. The body is immunodeficient.
- D. Helper T cells release histamine.
Correct Answer: A
Rationale: Step-by-step rationale:
1. During an allergic reaction, allergens trigger the release of IgE antibodies.
2. The allergen binds with IgE antibodies, leading to the activation of mast cells.
3. Activated mast cells release histamine and other inflammatory mediators.
4. This cascade of events causes allergic symptoms.
Therefore, option A is correct as it accurately describes the initial binding of allergen with IgE antibodies. Option B is incorrect as mast cells are activated, not deactivated. Option C is incorrect as the body is hypersensitive, not immunodeficient. Option D is incorrect as it is mast cells, not Helper T cells, that release histamine.
Which of the following is NOT a function of the immune system?
- A. Promoting wound healing
- B. Fighting cancer
- C. Increasing pathogen reproduction
- D. Eliminating cell debris
Correct Answer: C
Rationale: The correct answer is C: Increasing pathogen reproduction. The immune system's main function is to protect the body from pathogens and foreign invaders, not to promote their reproduction. A: Promoting wound healing is correct as the immune system helps in tissue repair. B: Fighting cancer is correct as the immune system plays a role in recognizing and destroying cancerous cells. D: Eliminating cell debris is correct as the immune system helps in clearing out dead or damaged cells to maintain tissue health.