Nokea
What are the effects of histamine released from mast cells?
- A. Increased vascular permeability and bronchoconstriction
- B. Neutralization of antigens and opsonization
- C. Complement activation and T cell proliferation
- D. Direct lysis of pathogens
Correct Answer: A
Rationale: The correct answer is A because histamine released from mast cells causes increased vascular permeability, leading to edema, and bronchoconstriction, contributing to respiratory symptoms. This is a key mechanism in allergic reactions.
B: Neutralization of antigens and opsonization are functions of antibodies, not histamine.
C: Complement activation and T cell proliferation are separate immune responses not mediated by histamine.
D: Direct lysis of pathogens is typically carried out by immune cells like macrophages and natural killer cells, not histamine.
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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.
Which patient would be most likely to be cured with chemotherapy as a treatment measure?
- A. Small cell lung cancer
- B. New neuroblastoma
- C. Small tumor of the bone
- D. Large hepatocellular carcinoma
Correct Answer: B
Rationale: Neuroblastoma, especially in newly diagnosed cases, is highly responsive to chemotherapy and has a higher likelihood of cure.
T regulatory cells are NOT
- A. Generated in the thymus upon expression of Foxp3
- B. Generated in the periphery in response to cytokines
- C. Able to inhibit effector T cells
- D. Able to cause immunity
Correct Answer: D
Rationale: The correct answer is D because T regulatory cells are known to suppress immune responses and promote immune tolerance, which is opposite to causing immunity. Choice A is incorrect because T regulatory cells are indeed generated in the thymus upon expression of Foxp3. Choice B is incorrect as T regulatory cells can also be generated in the periphery in response to cytokines. Choice C is incorrect as T regulatory cells are known to inhibit effector T cells to regulate immune responses.
What condition is associated with C1q deficiency?
- A. Cancer
- B. Systemic lupus erythematosus (SLE)
- C. HIV/AIDS
- D. Chronic obstructive pulmonary disease
Correct Answer: B
Rationale: Rationale: C1q is a component of the classical complement pathway, crucial for immune complex clearance. Its deficiency is associated with SLE due to impaired immune complex removal, leading to autoantibody deposition and inflammation. Cancer, HIV/AIDS, and COPD are not directly linked to C1q deficiency.
Identify the correct statement(s). In prokaryotes:
- A. Translation begins after transcription is finished.
- B. Messenger RNA is not co-linear with the DNA template.
- C. 5s, 16s, and 28s ribosomal RNA's are present.
- D. 50s and 30s ribosomal subunits are necessary for protein synthesis.
Correct Answer: d
Rationale: The correct answer is D because in prokaryotes, 50s and 30s ribosomal subunits combine to form the 70s ribosome, which is necessary for protein synthesis. Firstly, ribosomes are composed of two subunits, and in prokaryotes, these are the 50s and 30s subunits. Secondly, these subunits come together during translation to form the functional ribosome. Therefore, these ribosomal subunits are indeed necessary for protein synthesis in prokaryotes.
A: Incorrect. Translation can begin before transcription is finished in prokaryotes due to their lack of a nuclear membrane.
B: Incorrect. Messenger RNA in prokaryotes is co-linear with the DNA template as they do not undergo RNA splicing like eukaryotes.
C: Incorrect. In prokaryotes, the ribosomal RNA present is the 16s, 23s, and 5s, not 28s.