Nokea
The bacterial cytoplasmic membrane contains:
- A. ester-linked phospholipids, but no sterols
- B. ester-linked phospholipids and sterols
- C. ether-linked phospholipids, but no sterols
- D. ether-linked phospholipids, sulfolipids, and glycolipids
Correct Answer: A
Rationale: The correct answer is A because bacterial cytoplasmic membranes typically contain ester-linked phospholipids but no sterols. Ester-linked phospholipids are the main component of bacterial cell membranes, providing structure and function. Sterols, like cholesterol, are not commonly found in bacterial membranes. Choice B is incorrect because sterols are not present in bacterial membranes. Choice C is incorrect because ether-linked phospholipids are more commonly found in archaea, not bacteria. Choice D is incorrect because sulfolipids and glycolipids are not primary components of bacterial cytoplasmic membranes.
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Which of the following are not typically found within secondary lymphoid tissues?
- A. naïve lymphocytes
- B. Hematopoietic stem cells
- C. Dendritic cells
- D. Antigen
Correct Answer: B
Rationale: Correct Answer: B - Hematopoietic stem cells are not typically found within secondary lymphoid tissues because they are located in the bone marrow where they give rise to various blood cells. In contrast, secondary lymphoid tissues like lymph nodes and spleen primarily consist of mature immune cells and support immune responses. Naïve lymphocytes (A), dendritic cells (C), and antigens (D) are commonly found in secondary lymphoid tissues as they play crucial roles in the immune response.
Severe combined immunodeficiency (SCID) is a disease caused by:
- A. Infection with human immunodeficiency virus
- B. One of several inherited genetic mutations
- C. Deficiency of both innate and adaptive immune components
- D. Deficiency of hematopoietic stem cells
Correct Answer: B
Rationale: Step 1: SCID is a genetic disorder affecting the immune system.
Step 2: Inherited genetic mutations cause abnormalities in immune cells.
Step 3: These mutations lead to severe deficiencies in immune function.
Step 4: Choice B accurately reflects the genetic basis of SCID.
Summary: Choice A is incorrect because SCID is not caused by HIV. Choice C is incorrect as it oversimplifies the immune deficiencies in SCID. Choice D is incorrect because SCID primarily affects immune cells, not stem cells.
Which of the following statements is NOT true? The SARS coronavirus
- A. Caused an epidemic in 2003 that registered 10% mortality rate
- B. Caused an acute infection of the lungs classified as acute respiratory distress syndrome
- C. Is also the causal agent of MERS (Middle East Respiratory Syndrome)
- D. Is thought to have been transmitted from bats to civets and from civets to humans
Correct Answer: C
Rationale: The correct answer is C because the statement that SARS coronavirus is also the causal agent of MERS is false. MERS (Middle East Respiratory Syndrome) is caused by a different coronavirus called MERS-CoV. SARS-CoV caused the 2003 epidemic with a 10% mortality rate, which aligns with statement A. Statement B is correct as SARS-CoV does cause an acute infection of the lungs known as acute respiratory distress syndrome. Statement D is also true as SARS-CoV is believed to have been transmitted from bats to civets and then to humans. Therefore, the incorrect statement is C.
The inflammatory response produced
- A. by microbial-infected cells
- B. Internal tissue injury
- C. migration of erythrocyts from the spleen
- D. All above
Correct Answer: D
Rationale: The correct answer is D. The inflammatory response can be triggered by microbial-infected cells releasing cytokines, internal tissue injury leading to the release of inflammatory mediators, and the migration of erythrocytes from the spleen in response to inflammation. Therefore, all of the choices - A, B, and C - are correct in contributing to the inflammatory response. Each option plays a role in the complex cascade of events that lead to inflammation.
Which of the following statements is incorrect?
- A. Activation of receptors such as TLRs often precedes inflammasome formation
- B. Extracellular ATP triggers inflammasome formation
- C. Some environmental triggers, such as asbestos, can induce inflammasome formation
- D. NLRP3 is found in complex with pro-caspase 1 in resting, non-activated cells
Correct Answer: D
Rationale: The correct answer is D because NLRP3 is not found in complex with pro-caspase 1 in resting, non-activated cells. Inflammasome formation requires assembly of NLRP3 with ASC and pro-caspase 1. Choices A, B, and C are correct statements because activation of receptors like TLRs can trigger inflammasome formation, extracellular ATP can induce inflammasome formation, and environmental triggers such as asbestos can also lead to inflammasome activation.