Nokea
What is the key immune cell involved in granuloma formation?
- A. Mast cells
- B. Macrophages
- C. Neutrophils
- D. Dendritic cells
Correct Answer: B
Rationale: The correct answer is B: Macrophages. Macrophages are key immune cells involved in granuloma formation. They play a crucial role in engulfing and processing pathogens or foreign particles, leading to the formation of granulomas as part of the body's immune response. Mast cells (A) are primarily involved in allergic reactions. Neutrophils (C) are important in the initial immune response to infections but are not typically associated with granuloma formation. Dendritic cells (D) are important in antigen presentation and activation of T cells, but they are not the primary immune cells involved in granuloma formation.
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Polyclonal antibodies made in response to a given antigen will be:
- A. Derived from multiple B cell clones
- B. A mixture of different affinities
- C. A mixture of different antibody classes
- D. All options are correct
Correct Answer: D
Rationale: Step-by-step rationale for why Answer D is correct:
1. Polyclonal antibodies are produced by multiple B cell clones in response to an antigen (Choice A).
2. These antibodies have varying affinities due to the diversity of B cell clones involved (Choice B).
3. Different antibody classes, such as IgM, IgG, IgA, etc., are produced by different B cells (Choice C).
4. Therefore, all options are correct as polyclonal antibodies exhibit these characteristics.
Identify the fluid that is least possible to transmit AIDS.
- A. Blood
- B. Breast milk
- C. Semen
- D. Saliva
Correct Answer: D
Rationale: The correct answer is D: Saliva. Saliva has very low levels of HIV, making it least likely to transmit AIDS. HIV transmission requires direct contact with infected bodily fluids containing high viral loads, such as blood, breast milk, and semen. Saliva does not typically contain enough HIV to transmit the virus, as it has enzymes that can inhibit HIV. Therefore, the risk of HIV transmission through saliva is extremely low compared to the other fluids listed.
Compared to naïve T cells, memory T cells:
- A. Take less time to become activated
- B. Have less need for costimulation during activation
- C. Have a much longer life span
- D. All of the above are correct
Correct Answer: D
Rationale: Memory T cells, compared to naïve T cells, take less time to become activated as they have previously encountered the antigen. They also have less need for costimulation during activation due to their enhanced sensitivity. Furthermore, memory T cells have a much longer life span, allowing for a more rapid and robust immune response upon re-exposure to the antigen. Therefore, all of the statements in choices A, B, and C are correct, making option D the correct answer.
What is the correct order of steps needed for 2nd generation sequencing?
- A. DNA fragmentation, DNA isolation, amplification, primer ligation, sequencing
- B. Amplification, primer ligation, sequencing, DNA fragmentation, DNA isolation
- C. DNA isolation, DNA fragmentation, primer ligation, amplification, sequencing
- D. Sequencing, DNA isolation, DNA fragmentation, primer ligation, amplification
Correct Answer: C
Rationale: The correct order of steps for 2nd generation sequencing is C: DNA isolation, DNA fragmentation, primer ligation, amplification, sequencing. Firstly, DNA isolation is crucial to extract the DNA from the sample. Next, DNA fragmentation breaks the DNA into smaller fragments for sequencing. Primer ligation involves attaching primers to the DNA fragments. Amplification is necessary to make multiple copies of the DNA fragments for sequencing. Finally, sequencing is the process of determining the nucleotide sequence of the DNA fragments. This order ensures that the DNA is properly prepared and amplified before sequencing, leading to accurate results.
Choices A, B, and D are incorrect because they do not follow the correct sequence of steps required for 2nd generation sequencing. Incorrect sequences may lead to errors in the sequencing process and inaccurate results.
Which characteristics describe Pneumocystis jiroveci infection, an opportunistic disease that can be associated with HIV?
- A. May cause fungal meningitis
- B. Diagnosed by lymph node biopsy
- C. Pneumonia with dry, nonproductive cough
- D. Viral retinitis, stomatitis, esophagitis, gastritis, or colitis
Correct Answer: C
Rationale: Pneumocystis jiroveci pneumonia typically presents with a dry, nonproductive cough, shortness of breath, and fever.