Complement lyses cells by

Correct Answer: C

Rationale: The correct answer is C because complement lyses cells by forming a membrane attack complex (MAC) which involves the insertion of complement proteins into the cell membrane, leading to cell lysis. Choices A, B, and D are incorrect as complement does not lyse cells through enzymatic digestion, activation of adenylate cyclase, or inhibition of elongation factor 2. Complement-mediated lysis specifically involves the formation of MAC to disrupt the target cell membrane.

Correct Answer: A

Rationale: The correct answer is A: They have the same amino acid sequence. This statement is incorrect because the variable regions of heavy chains and light chains in an antibody molecule have different amino acid sequences. The variable regions are responsible for binding to specific antigens, making choice B correct. The heavy and light chains are encoded by different genes on the same chromosome, making choice C incorrect. Both heavy and light chains contain hypervariable regions that contribute to antigen binding specificity, making choice D correct. Overall, the variable regions of heavy and light chains have distinct amino acid sequences, contributing to the diversity and specificity of antibodies.

Correct Answer: C

Rationale: The correct answer is C: being vaccinated against chicken pox. Vaccination stimulates the immune system to produce antibodies against the specific microbe, providing protection. Antibiotics (choice A) target bacteria, not viruses like chicken pox. While a well-balanced diet (choice B) supports overall health, it doesn't specifically stimulate the immune system against a microbe. Hormones in mother's milk (choice D) provide passive immunity but do not actively stimulate the immune system to produce antibodies. Vaccination is the most direct and effective way to stimulate the immune system for targeted protection.

Correct Answer: D

Rationale: Step 1: RAST testing is used to detect allergen-specific IgE antibodies in the blood. Step 2: Seasonal allergies are typically caused by exposure to specific allergens. Step 3: IgE is elevated in response to exposure to specific antigens, which matches the purpose of RAST testing. Step 4: IgG is not specific to allergies but is more related to various infections. IgM is for acute infections. IgA is for mucosal protection. Step 5: Therefore, the correct answer is D (IgE) as it aligns with the purpose of RAST testing and the client's symptom history.

Correct Answer: B

Rationale: The correct answer is B - A progressive, circular rash- often develops at the bite site, but can also develop at other sites such as the thighs and knees. This is the early manifestation of Lyme disease known as erythema migrans. The rash typically appears within 3-30 days after a tick bite and expands gradually. Double vision (Choice A) is associated with disseminated Lyme disease in the late stage. Severe joint swelling (Choice C) is not a common early symptom of Lyme disease. Chronic fatigue (Choice D) may occur in later stages but is not a specific early manifestation of Lyme disease.