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NAD and FAD are hydrogen carriers, but cytochromes are electron carriers in bacteria. What happens to the protons (Hâº) in electron transport chains?
- A. They go into solution inside the cytoplasm.
- B. They are taken back by NAD and FAD.
- C. They are carried from cytochromes to oxygen to form water.
- D. They go into solution outside the cytoplasmic membrane.
Correct Answer: D
Rationale: The correct answer is D because in the electron transport chain, protons (H⁺) are pumped across the membrane to create a proton gradient. This gradient is utilized by ATP synthase to produce ATP. Therefore, protons go into solution outside the cytoplasmic membrane. Choices A and B are incorrect because protons do not simply stay in the cytoplasm or get taken back by NAD and FAD. Choice C is incorrect as protons do not directly form water when carried by cytochromes.
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A client has been newly diagnosed with systemic lupus erythematosus and is reviewing self-care measures with the nurse. Which statement by the client indicates a need to review the material?
- A. I will avoid direct sunlight as much as possible.
- B. Baby powder is good for the constant sweating.
- C. Grouping errands will help prevent fatigue.
- D. Rest time will have to become a priority.
Correct Answer: B
Rationale: The correct answer is B. Baby powder is not recommended for individuals with systemic lupus erythematosus, as it can irritate the skin and worsen symptoms. A: Avoiding direct sunlight is crucial due to photosensitivity. C: Grouping errands helps conserve energy. D: Rest is important to manage fatigue. Summary: A, C, and D are all appropriate self-care measures for a client with systemic lupus erythematosus, while using baby powder is not recommended.
A major antibody-mediated mechanism of defense against parasitic worms involves:
- A. Neutrophil degranulation
- B. Opsonization
- C. Triggering of physiological responses (such as coughing) that expel the worm
- D. Neutralization by IgE along the mucosal surface of the gut
Correct Answer: D
Rationale: The correct answer is D because neutralization by IgE along the mucosal surface of the gut is a major antibody-mediated mechanism against parasitic worms. IgE binds to antigens on the worm's surface, leading to the release of histamine and other mediators that help expel the worm. Neutrophil degranulation (A) is more associated with bacterial infections, opsonization (B) is mainly for phagocytosis of pathogens, and triggering physiological responses (C) is not a direct antibody-mediated defense against parasitic worms.
What is a characteristic disease associated with Type III hypersensitivity?
- A. Grave's disease
- B. Goodpasture's syndrome
- C. Systemic lupus erythematosus (SLE)
- D. Contact dermatitis
Correct Answer: C
Rationale: The correct answer is C: Systemic lupus erythematosus (SLE). In Type III hypersensitivity, immune complexes form and deposit in tissues, leading to inflammation and tissue damage. SLE is a classic example of a Type III hypersensitivity reaction where these immune complexes deposit in various organs causing systemic inflammation and damage. Graves's disease (A) is an example of Type II hypersensitivity, where autoantibodies target cell-surface receptors. Goodpasture's syndrome (B) is a Type II hypersensitivity disease affecting the kidneys and lungs. Contact dermatitis (D) is a Type IV hypersensitivity reaction mediated by T cells, not involving immune complexes. Therefore, the correct answer is C as it aligns with the characteristic disease associated with Type III hypersensitivity.
The process of somatic hypermutation:
- A. Can lead to the formation of antibodies with higher affinity for the antigen
- B. Occurs mainly in the CDR regions of immunoglobulin heavy and light chain genes
- C. Occurs in germinal centres
- D. All of the above are correct
Correct Answer: D
Rationale: The correct answer is D because somatic hypermutation can lead to the formation of antibodies with higher affinity for the antigen by introducing point mutations in the variable regions of immunoglobulin genes. This process mainly occurs in the complementarity-determining regions (CDRs) of immunoglobulin heavy and light chain genes, which are critical for antigen binding. Somatic hypermutation takes place in the germinal centers of secondary lymphoid organs, where B cells undergo rapid proliferation and selection based on antigen binding affinity. Therefore, all the statements in choices A, B, and C are correct, making option D the right answer.
Which of the following statements about the 2009 H1N1 pandemic is NOT true
- A. Caused by a virus originated from 4 different strains
- B. Individuals over 60 were especially affected
- C. A level 6 pandemic phase was declared by WHO in June 2009
- D. 2009 H1N1 is considered moderately virulent in terms of severity of disease
Correct Answer: B
Rationale: The correct answer is B. Individuals over 60 were not especially affected by the 2009 H1N1 pandemic. This is because older individuals had some level of immunity due to previous exposure to similar strains. The other choices are incorrect because: A: The 2009 H1N1 virus originated from a combination of 2 different strains, not 4. C: WHO declared a level 6 pandemic phase in June 2009. D: The 2009 H1N1 virus was considered less virulent compared to other strains.