Nokea
Human immunodeficiency virus (HIV) infects:
- A. CD4+ T cells
- B. B cells
- C. CD8+ T cells
- D. All of the above
Correct Answer: A
Rationale: The correct answer is A: CD4+ T cells. HIV primarily infects CD4+ T cells by binding to the CD4 receptor and a co-receptor, usually CCR5 or CXCR4. CD4+ T cells are crucial for coordinating the immune response. B cells (choice B) are not typically infected by HIV. CD8+ T cells (choice C) can be indirectly affected by HIV, but they are not the primary target of the virus. Therefore, the correct choice is A as it accurately reflects the primary target cells of HIV infection.
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Viral antigenic shift
- A. Is caused by multiple random mutations
- B. Is caused by a single mutation
- C. It affects only internal viral proteins not recognized by preexisting antibodies
- D. It refers to the appearance of new HA variants not recognized by preexisting antibodies
Correct Answer: D
Rationale: Step 1: Viral antigenic shift involves major changes in the surface proteins of the virus, particularly the hemagglutinin (HA) protein.
Step 2: These changes result in the emergence of new variants that are not recognized by preexisting antibodies.
Step 3: This process is distinct from antigenic drift, which involves minor changes due to random mutations.
Step 4: Choice D correctly states that viral antigenic shift refers to the appearance of new HA variants not recognized by preexisting antibodies.
Summary: Choice A is incorrect because viral antigenic shift is not caused by multiple random mutations. Choice B is incorrect as antigenic shift involves major changes, not a single mutation. Choice C is incorrect as it affects surface proteins like HA, not just internal proteins.
The nurse is presenting a community education program related to cancer prevention. Based on current cancer death rates, the nurse emphasizes what as the most important preventive action for both women and men?
- A. Smoking cessation
- B. Routine colonoscopies
- C. Protection from ultraviolet light
- D. Regular examination of reproductive organs
Correct Answer: A
Rationale: Smoking cessation is the most significant preventive action because smoking is a leading cause of preventable cancer deaths.
Identify the fluid that is least possible to transmit AIDS.
- A. Blood
- B. Breast milk
- C. Semen
- D. Saliva
Correct Answer: D
Rationale: The correct answer is D: Saliva. Saliva has very low levels of HIV, making it least likely to transmit AIDS. HIV transmission requires direct contact with infected bodily fluids containing high viral loads, such as blood, breast milk, and semen. Saliva does not typically contain enough HIV to transmit the virus, as it has enzymes that can inhibit HIV. Therefore, the risk of HIV transmission through saliva is extremely low compared to the other fluids listed.
A segment of DNA that reads the same from forward and backward is called_____.
- A. Complementary DNA
- B. Palindromic DNA
- C. Copy DNA
- D. Transcribed DNA
Correct Answer: B
Rationale: The correct answer is B: Palindromic DNA. Palindromic DNA refers to a segment of DNA that reads the same from both directions. This property occurs when the nucleotide sequence on one strand of DNA is the reverse complement of the nucleotide sequence on the other strand. This symmetry allows the DNA sequence to be read the same forward and backward.
Incorrect choices:
A: Complementary DNA - Complementary DNA refers to a synthesized DNA strand that is complementary to a given DNA sequence.
C: Copy DNA - Copy DNA is not a commonly used term in molecular biology.
D: Transcribed DNA - Transcribed DNA refers to DNA that has been converted into RNA through the process of transcription, not DNA that reads the same forward and backward.
What is the prevalence of sarcoidosis in Ireland?
- A. One of the lowest globally
- B. Among the highest globally
- C. Similar to the global average
- D. Extremely rare
Correct Answer: B
Rationale: The correct answer is B: Among the highest globally. Sarcoidosis prevalence in Ireland is relatively high compared to other regions. This is due to genetic factors, environmental influences, and possibly healthcare practices. Sarcoidosis rates vary worldwide, with Ireland being noted for its higher prevalence. Choices A, C, and D are incorrect because Ireland's sarcoidosis prevalence is not among the lowest globally, similar to the global average, or extremely rare.