Nokea
What type of antibodies predominate in the secondary immune response?
- A. IgM
- B. IgE
- C. IgG
- D. IgD
Correct Answer: C
Rationale: The correct answer is C: IgG. In the secondary immune response, IgG antibodies predominate due to memory B cells rapidly producing them upon re-exposure to the same antigen. IgG provides long-lasting immunity and is more efficient in neutralizing pathogens. IgM (A) is the primary antibody in the initial immune response. IgE (B) is involved in allergic reactions. IgD (D) functions as a receptor on B cells.
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Which of the following early contributors to the development of immunology is paired up properly with his or her accomplishment?
- A. Louis Pasteur: demonstrated that cowpox vaccination can protect from smallpox
- B. Paul Ehrlich: identified lymphocytes as the cells mediating adaptive immunity
- C. MacFarlane Burnet: proposed the side-chain theory of antibodies which suggested that multiple antigen receptors are expressed on immune cells
- D. Robert Koch: developed techniques to grow pure bacterial cultures
Correct Answer: D
Rationale: Rationale: Robert Koch is correctly paired with developing techniques to grow pure bacterial cultures. Koch's work laid the foundation for bacteriology and allowed for the isolation and identification of specific disease-causing bacteria. This technique, known as Koch's postulates, revolutionized the field of microbiology by linking specific pathogens to specific diseases.
Summary:
A: Louis Pasteur - Incorrect. While Pasteur is known for his work in vaccination and pasteurization, the provided accomplishment is associated with Edward Jenner, not Pasteur.
B: Paul Ehrlich - Incorrect. Ehrlich is known for his work on immunology and coined the term "magic bullet," but he did not identify lymphocytes as cells mediating adaptive immunity.
C: MacFarlane Burnet - Incorrect. Burnet is known for his clonal selection theory, not the side-chain theory of antibodies as described in the choice.
What is a primary reason that the normal immune response fails to contain the HIV infection?
- A. CD4+ T cells become infected with HIV and are destroyed.
- B. The virus inactivates B cells, preventing the production of HIV antibodies.
- C. Natural killer cells are destroyed by the virus before the immune system can be activated.
- D. Monocytes ingest infected cells, differentiate into macrophages, and shed viruses in body tissues.
Correct Answer: A
Rationale: HIV specifically targets CD4+ T cells, depleting the immune system's ability to mount an effective response against pathogens.
Your patient with rheumatoid arthritis (RA) is taking prednisone (Deltasone) and naproxen (Alleve) to reduce inflammation and joint pain. Which of these symptoms is the strongest indicator that a change in therapy may be necessary?
- A. The patient states that the RA symptoms are worst in the morning.
- B. The patient complains about having dry eyes.
- C. The patient has round and moveable nodules just under the skin.
- D. The patient has stools that are very dark in color.
Correct Answer: D
Rationale: Dark stools can indicate gastrointestinal bleeding which is a serious side effect of NSAIDs like naproxen. This requires immediate attention and possibly a change in therapy. The other symptoms while related to RA do not indicate an urgent need for a change in treatment.
Which of the following is NOT a property of CD8+ T cells?
- A. They typically differentiate into cytotoxic T cells (Tc)
- B. They always recognize peptide antigen in association with an MHC molecule
- C. They are important in defense against intracellular pathogens
- D. They are the cell responsible for antibody-dependent cell-mediated cytotoxicity
Correct Answer: D
Rationale: The correct answer is D because CD8+ T cells are not responsible for antibody-dependent cell-mediated cytotoxicity. A is correct as CD8+ T cells differentiate into cytotoxic T cells. B is correct as CD8+ T cells recognize peptide antigens with MHC molecules. C is correct as CD8+ T cells are vital in defense against intracellular pathogens. D is incorrect as CD8+ T cells do not mediate cell cytotoxicity through antibodies.
The oxidation-reduction pairs X/XHâ‚‚ and Y/YHâ‚‚ have reduction potentials of -50 and +75 millivolts, respectively. This means that electrons would most likely be removed from ______ to reduce ______.
- A. XHâ‚‚, Y
- B. Y, XHâ‚‚
- C. YHâ‚‚, X
- D. Y, YHâ‚‚
Correct Answer: A
Rationale: The correct answer is A: XHâ‚‚, Y. This is because the reduction potential of -50 mV for X/XHâ‚‚ indicates that X is more likely to lose electrons compared to Y with a reduction potential of +75 mV. Therefore, electrons would be removed from XHâ‚‚ (X) to reduce Y. Choice B is incorrect because Y has a higher reduction potential than XHâ‚‚, so electrons would not be removed from Y to reduce XHâ‚‚. Choices C and D are also incorrect as they do not consider the relative reduction potentials of X/XHâ‚‚ and Y/YHâ‚‚.