What signs would you expect to see in a patient when diagnosing malaria? (Choose one)

Correct Answer: B

Rationale: The correct answer is B: Fever. In diagnosing malaria, fever is a key symptom due to the cyclic nature of the disease. Malaria typically presents with recurrent bouts of fever, which is caused by the cycle of the parasite invading and multiplying in red blood cells. The other choices (A: Rash, C: Chest pain, D: Hair loss) are not typical signs of malaria. Rash is more commonly seen in diseases like dengue fever, chest pain could be indicative of other conditions like pneumonia or heart issues, and hair loss is not a characteristic symptom of malaria. Therefore, fever is the most characteristic and essential sign to consider when diagnosing malaria.

Correct Answer: C

Rationale: The correct answer is C because genetically identical individuals have the same major histocompatibility complex (MHC) antigens, so there is no immune response or rejection of grafts. Minor histocompatibility antigens (choice A) are not relevant in this case. Hyperacute rejection (choice B) occurs due to pre-existing antibodies, which is not a factor in genetically identical twins. Choice D is incorrect as both kidney and skin grafts would be accepted between identical twins due to genetic similarity.

Correct Answer: C

Rationale: The correct answer is C: antigen-IgG complexes. The classic complement pathway is initiated when C1 binds to antigen-IgG complexes. This interaction triggers a cascade of enzymatic reactions leading to opsonization, inflammation, and cell lysis. The other choices are incorrect because A (antigen) does not directly activate the complement pathway, B (factor B) is part of the alternative pathway, and D (bacterial lipopolysaccharides) activate the lectin pathway, not the classic pathway.

Correct Answer: B

Rationale: The correct answer is B because membrane-bound IgM and IgD on a B cell have identical variable regions (VH and VL) but different constant regions (CH). This is important for B cell receptor diversity while maintaining specificity. Choice A is incorrect as they have different heavy and light chains. Choice C is incorrect because they have different constant regions. Choice D is incorrect as they have identical variable regions.

Correct Answer: D

Rationale: The correct answer is D because when adult AB spleen cells are injected into a newborn B mouse, the recipient's immune system is still developing. This allows the injected cells to establish tolerance towards strain A antigens. This process is known as neonatal tolerance induction. Option A is incorrect because the immune system of the recipient is not mature enough to mount a strong response to destroy the injected cells. Option B is unlikely as the injected cells would likely interact with the recipient's immune system. Option C is less likely as the immune system of the newborn mouse is not fully developed to initiate a graft-versus-host reaction efficiently.