Nokea
Which type of immunity is the result of contact with the antigen through infection and is the longest lasting type of immunity?
- A. Active innate immunity
- B. Passive innate immunity
- C. Active acquired immunity
- D. Passive acquired immunity
Correct Answer: C
Rationale: Active acquired immunity results from direct exposure to an antigen, such as through infection or vaccination. It involves the body's immune system recognizing and remembering the antigen, leading to long-lasting immunity.
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What underpins most functions of the immune system?
- A. Secondary lymphoid tissues
- B. Haematopoietic stem cells in the bone marrow
- C. Mucosal immune system activity
- D. Rapid cytokine suppression
Correct Answer: B
Rationale: The correct answer is B: Haematopoietic stem cells in the bone marrow. These cells are responsible for generating all immune cells, including lymphocytes, macrophages, and dendritic cells. They continuously replenish the immune system, allowing for proper immune function. Secondary lymphoid tissues (choice A) play a role in immune responses but are not the primary underpinning. Mucosal immune system activity (choice C) is important for defense at mucosal surfaces but is not the foundation of immune function. Rapid cytokine suppression (choice D) is a regulatory mechanism, not the fundamental basis of immune system functions.
Cardiac output
- A. coronary insufficient circulation
- B. A defect in one or more heart valves
- C. Disorder in a heartbeat
- D. Amount of blood/minute pumped into systemic circuit
Correct Answer: D
Rationale: The correct answer is D because cardiac output refers to the amount of blood pumped by the heart into the systemic circulation per minute. It is a crucial measure of heart function. Option A, coronary insufficient circulation, specifically refers to inadequate blood flow to the heart muscle itself, not overall cardiac output. Option B, a defect in heart valves, would affect the efficiency of blood flow but not necessarily the total amount of blood pumped. Option C, a disorder in heart rhythm, relates to irregular heartbeat patterns rather than the volume of blood pumped. Therefore, D is the correct choice as it directly relates to the definition of cardiac output.
In the 1960s, smallpox was endemic:
- A. In many developing countries
- B. In North America
- C. In England
- D. Globally
Correct Answer: A
Rationale: The correct answer is A: In many developing countries. Smallpox was indeed endemic in many developing countries in the 1960s, causing significant morbidity and mortality. This is supported by historical records and epidemiological data from that time period. Choices B, C, and D are incorrect because smallpox was not endemic in North America, England, or globally during the 1960s. Smallpox eradication efforts led to the global eradication of the disease in 1980, but in the 1960s, it was still prevalent in many developing countries.
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.
APECED is a rare autoimmune disease caused by deficiency of
- A. CTLA-4
- B. AIRE
- C. Tregs
- D. TGF-β
Correct Answer: B
Rationale: The correct answer is B: AIRE. APECED (Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy) is caused by mutations in the AIRE gene. AIRE is responsible for regulating the expression of self-antigens in the thymus, crucial for the development of immune tolerance. Deficiency in AIRE leads to the production of autoantibodies and autoimmune manifestations.
Incorrect options:
A: CTLA-4 is involved in downregulating immune responses but is not directly linked to APECED.
C: Tregs (regulatory T cells) play a role in immune tolerance, but APECED is not directly caused by their deficiency.
D: TGF-β is a cytokine involved in immune regulation, but its deficiency does not lead to APECED.