Nokea
Which T lymphocytes are involved in direct attack and destruction of foreign pathogens?
- A. Dendritic cells
- B. Natural killer cells
- C. T helper (CD4) cells
- D. T cytotoxic (CD8) cells
Correct Answer: D
Rationale: T cytotoxic (CD8) cells directly attack and destroy infected or abnormal cells, making them crucial for eliminating pathogens.
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T cell receptor and B cell receptor genes both undergo:
- A. Somatic hypermutation
- B. Germline gene rearrangement
- C. Isotype switching
- D. Both A and B are correct
Correct Answer: B
Rationale: The correct answer is B, germline gene rearrangement. T cell receptor and B cell receptor genes both undergo germline gene rearrangement during lymphocyte development, where gene segments are rearranged to generate diverse antigen receptor specificities. Somatic hypermutation and isotype switching are processes specific to B cells in the adaptive immune response, not T cells. Therefore, choices A and C are incorrect. Choice D is incorrect as well since somatic hypermutation is not a process involved in T cell receptor gene rearrangement.
Phagocytosis is not a characteristic of which groups?
- A. protozoans
- B. algae
- C. fungi
- D. Archaea
Correct Answer: D
Rationale: Phagocytosis is a process where cells engulf and digest particles. Archaea lack membrane-bound organelles, including phagosomes, making phagocytosis impossible. Protozoans, algae, and fungi have the necessary cellular structures for phagocytosis. Therefore, the correct answer is D. Protozoans, algae, and fungi can perform phagocytosis due to their cellular structure and function, making choices A, B, and C incorrect.
Which of the following is NOT true about the definition of acquired passive immunity
- A. Breast milk is an example
- B. It provides short term protection
- C. Can be transferred through the placenta
- D. It can be used for disease prevention
Correct Answer: E
Rationale: I'm sorry, but the correct answer is not provided in the choices given. Acquired passive immunity refers to the transfer of antibodies from one individual to another. Breast milk, placental transfer, short-term protection, and disease prevention are all characteristics of acquired passive immunity. Therefore, the correct answer is not presented in the options provided.
The site of ATP synthesis in microorganisms includes:
- A. cytoplasmic membranes
- B. cell walls
- C. chloroplasts
- D. mitochondria
Correct Answer: B
Rationale: The correct answer is B: cell walls. Microorganisms, such as bacteria and archaea, do not have mitochondria or chloroplasts. ATP synthesis in microorganisms primarily occurs in the cell walls through processes like glycolysis and fermentation. Cytoplasmic membranes are involved in electron transport and ATP synthesis in prokaryotic cells, not cell walls. Chloroplasts are only present in photosynthetic organisms, not in microorganisms.
Which dietary change is most beneficial in reducing the risk of colorectal cancer?
- A. Increased fiber intake
- B. High-fat diet
- C. Reduced carbohydrate consumption
- D. Increased protein intake
Correct Answer: A
Rationale: Increased fiber intake promotes healthy digestion and reduces the risk of colorectal cancer.