Nokea
Avian Influenza has not so far caused a human pandemic because
- A. Avian flu causes only mild infection in humans compared to birds
- B. Avian flu recognize a variant of sialic acid found only on avian cells
- C. Avian flu recognizes a variant of sialic acid only found in deep tissues of humans
- D. Of cross-protection obtained from the annual vaccine
Correct Answer: C
Rationale: The correct answer is C because avian influenza has not caused a human pandemic due to the fact that it recognizes a variant of sialic acid only found in deep tissues of humans. This unique binding preference prevents efficient human-to-human transmission, which is crucial for a pandemic to occur. Choice A is incorrect as avian flu can cause severe illness in humans. Choice B is incorrect because avian flu recognizing a variant of sialic acid found only on avian cells would not prevent a pandemic in humans. Choice D is incorrect as there is no specific annual vaccine for avian influenza.
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What type of immunity is provided by T lymphocytes?
- A. Humoral immunity
- B. Cell-mediated immunity
- C. Passive immunity
- D. Innate immunity
Correct Answer: B
Rationale: The correct answer is B: Cell-mediated immunity. T lymphocytes are a type of white blood cell that plays a critical role in cell-mediated immunity by directly attacking infected cells and coordinating the immune response. This type of immunity is essential for fighting intracellular pathogens such as viruses and certain bacteria.
A: Humoral immunity is mediated by B cells and involves the production of antibodies to neutralize pathogens. T lymphocytes do not directly participate in humoral immunity.
C: Passive immunity is acquired through the transfer of antibodies from one individual to another, providing immediate protection. T lymphocytes are not involved in passive immunity.
D: Innate immunity is the body's first line of defense against pathogens and does not involve T lymphocytes, which are part of the adaptive immune response.
Which of the following are not examples of a terminal electron acceptor in anaerobic respiration?
- A. nitrate
- B. hydrogen sulfate
- C. iron hydroxide
- D. Hâ‚‚
Correct Answer: D
Rationale: The correct answer is D: H₂. In anaerobic respiration, H₂ can act as a terminal electron acceptor, so it is not an incorrect example. Nitrate, hydrogen sulfate, and iron hydroxide are all examples of terminal electron acceptors in anaerobic respiration. H₂ is commonly used in microbial processes as an electron donor, not as a terminal electron acceptor. This is because H₂ is typically oxidized to produce energy, rather than accepting electrons.
Vertebrate eyes are Single-lens eyes with
- A. Light is focused by the curved cornea and lens
- B. Changing the shape of the lens focuses near and far
- C. Photoreceptor cells in the retina detect light
- D. All above
Correct Answer: D
Rationale: The correct answer is D because vertebrate eyes have single-lens eyes where light is focused by the curved cornea and lens (A), and changing the shape of the lens allows for focusing at different distances (B). Additionally, photoreceptor cells in the retina detect light (C). Therefore, all of the above statements are true, making D the correct choice. Choice A is incorrect because it does not encompass the entire process of vision in vertebrate eyes, missing the role of changing the lens shape. Choice B is incorrect as it only addresses the lens shape without mentioning the role of the cornea in focusing light. Choice C is incorrect as it only focuses on the function of photoreceptor cells in the retina without considering the lens and cornea's role in focusing light.
Which of the following is a major site of immune complex deposition in systemic lupus erythematosus (SLE)?
- A. Thyroid
- B. Glomerular basement membrane
- C. Peripheral nerves
- D. Mast cells
Correct Answer: B
Rationale: The correct answer is B: Glomerular basement membrane. In SLE, immune complexes deposit in various tissues, leading to inflammation and damage. The glomerular basement membrane is a common site for immune complex deposition in SLE, resulting in lupus nephritis. The other choices are incorrect because immune complex deposition does not typically occur in the thyroid, peripheral nerves, or mast cells in SLE. Thyroid involvement in SLE is more related to autoimmune thyroiditis, while peripheral nerves are not a major site for immune complex deposition in this condition. Mast cells are primarily involved in allergic reactions and are not a major target in SLE.
The nurse is counseling a group of individuals over the age of 50 with average risk for cancer about screening tests for cancer. Which screening recommendation should be performed to screen for colorectal cancer?
- A. Barium enema every year
- B. Colonoscopy every 10 years
- C. Fecal occult blood every 5 years
- D. Annual prostate-specific antigen (PSA) and digital rectal exam
Correct Answer: B
Rationale: Colonoscopy every 10 years is recommended for colorectal cancer screening in individuals over 50 with average risk.