Nokea
Peyer's patches are found in the:
- A. Intestine
- B. Spleen
- C. Lungs
- D. Skin
Correct Answer: A
Rationale: Peyer's patches are lymphoid nodules located in the small intestine, specifically in the ileum. They play a crucial role in the immune response of the gut. The correct answer is A: Intestine because Peyer's patches are specifically found in the intestine. The other choices are incorrect because the spleen is a different organ involved in filtering blood, the lungs are primarily involved in respiration, and the skin is the body's largest organ responsible for protection and thermoregulation.
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Which of the following statements is most correct regarding Leishmania?
- A. Leishmaniasis is caused by an extracellular bacterium
- B. Leishmaniasis is associated with severe immunodeficiency
- C. An infected individual is less likely to suffer severe leishmaniasis if they make a TH2 rather than TH1 response to the pathogen
- D. Visceral leishmaniasis is the most severe form of leishmaniasis
Correct Answer: D
Rationale: The correct answer is D because visceral leishmaniasis is indeed the most severe form of leishmaniasis. Visceral leishmaniasis affects internal organs and can be fatal if left untreated.
A is incorrect because Leishmania is a protozoan parasite, not a bacterium. B is incorrect because leishmaniasis can affect individuals with normal immune systems, not just those with severe immunodeficiency. C is incorrect because a TH1 response is actually protective against severe leishmaniasis, not a TH2 response.
What statement accurately describes gene therapy?
- A. May activate a mutated gene that is functioning improperly.
- B. Is a risky technique under study for genetic diseases with no cure.
- C. Is frequently done by replacing a healthy gene with a mutated gene.
- D. Introduces a new gene into reproductive cells to help fight a genetic disease.
Correct Answer: B
Rationale: Gene therapy remains experimental and involves risks, aiming to treat genetic diseases by altering or replacing defective genes.
Which cells are responsible for antigen presentation to T cells?
- A. Plasma cells
- B. Antigen-presenting cells (APCs)
- C. NK cells
- D. Eosinophils
Correct Answer: B
Rationale: The correct answer is B: Antigen-presenting cells (APCs). APCs, such as dendritic cells, macrophages, and B cells, are specialized cells that capture, process, and present antigens to T cells to initiate an immune response. They express major histocompatibility complex (MHC) molecules for antigen presentation. Plasma cells (A) produce antibodies, NK cells (C) are involved in killing infected cells, and eosinophils (D) are primarily involved in parasitic infections and allergic responses, not antigen presentation to T cells.
What groups listed below have true cell walls?
- A. algae
- B. mycoplasmas
- C. Gram-positive bacteria
- D. fungi
Correct Answer: B
Rationale: The correct answer is B: mycoplasmas. Mycoplasmas have cell walls, which contain peptidoglycan, making them structurally similar to typical bacteria. Algae (choice A) have cell walls made of cellulose, Gram-positive bacteria (choice C) have cell walls containing thick layers of peptidoglycan, and fungi (choice D) have cell walls made of chitin. Mycoplasmas lack a cell wall, but they have a flexible cell membrane that provides them with shape and protection.
Flu neuraminidase is
- A. A protein that allows the virus to escape the host immune response
- B. A surface protein that allows the release of newly formed viral particles
- C. The target of Tamiflu
- D. Both B and C are correct
Correct Answer: D
Rationale: The correct answer is D because flu neuraminidase is a surface protein that allows the release of newly formed viral particles and it is also the target of Tamiflu. Neuraminidase helps the virus spread by cleaving sialic acid from host cells, facilitating the release of viral particles. Tamiflu inhibits neuraminidase, preventing the spread of the virus. Option A is incorrect because neuraminidase does not directly help the virus escape the host immune response. Option B is partially correct but incomplete without mentioning Tamiflu. Option C is also partially correct but incomplete without mentioning the role of neuraminidase in releasing viral particles.