In a mixed-lymphocyte culture, lymphocytes from person X, who is homozygous for the HLA-Dw7 allele, are irradiated and then cultured with lymphocytes from person Z... DNA synthesis is NOT stimulated. The proper conclusion to be drawn is that

Correct Answer: B

Rationale: The correct answer is B because if DNA synthesis is not stimulated in the mixed-lymphocyte culture, it indicates that person Z has at least one allele that is different from person X's HLA-Dw7 allele. This rules out person Z being homozygous for HLA-Dw7 (choice A) as there would be no difference in HLA alleles between the two individuals. Similarly, person Z being heterozygous for HLA-Dw7 (choice C) is too specific as it assumes only one specific allele is different. Choice D is incorrect as it states that person Z does not carry the HLA-Dw7 allele, which cannot be concluded definitively from the information provided. Therefore, the most reasonable conclusion is that person Z is either homozygous or heterozygous for HLA-Dw7 (choice B) since there is a lack of DNA synthesis stimulation, indicating a difference in HLA alleles between the two individuals.

Correct Answer: C

Rationale: Rationale: C is incorrect because heavy-chain switching can occur in hybridoma cells, leading to the production of different antibody isotypes besides IgM. This process allows for the generation of antibodies with diverse functions. A, B, and D are correct: A: The spleen cell component provides the ability to form antibody as it contributes the B-cell's ability to produce antibodies. B: The myeloma cell component provides the ability to grow indefinitely due to its immortal nature. D: The antibody produced by a hybridoma cell is homogeneous and directed against a single epitope due to the clonal nature of hybridoma cells.

Correct Answer: A

Rationale: The correct answer is A because bacteria interfering with normal life functions of the birds is the most likely explanation for the birds dying after eating infected worms. This is a logical explanation as bacterial invasion can lead to harmful effects on the host organism's health. Choice B is incorrect because the disease that killed the birds was not necessarily inherited. Choice C is incorrect as gene alterations in bacterial cells killing the birds is not a common or likely scenario. Choice D is incorrect as birds producing antigens in response to the bacteria would typically be a defense mechanism rather than a cause of death.

Correct Answer: B

Rationale: Step 1: Monitoring body temperature is crucial in SLE patients as fever can indicate disease exacerbation or infection. Step 2: Prompt reporting of any elevations allows for timely intervention and prevents complications. Step 3: Early detection and management of fever can improve outcomes and quality of life for patients. Summary: Choices A, C, and D are incorrect as they do not address the key concerns of monitoring for disease exacerbation or infection in SLE patients.

Correct Answer: B

Rationale: Certainly! The correct answer is B because applying lotion twice per day is a simple and effective way to moisturize dry skin, which is a common issue in clients with Systemic Lupus Erythematosus (SLE). Moisturizing helps to improve skin hydration and prevent further dryness and irritation. Explanation for why other choices are incorrect: - Choice A: Applying antibiotic cream is not recommended for dry skin in SLE clients as it is not the appropriate treatment. Topical corticosteroid creams are typically used for cutaneous manifestations of SLE. - Choice C: Using petroleum jelly once weekly may not provide sufficient moisturization for dry skin and may not be as effective as applying lotion twice daily. - Choice D: Avoiding moisturizing the skin can worsen dryness and skin irritation, which is not recommended for managing dry skin in SLE clients.