Nokea
In which of the following locations can IgA be found?
- A. In the intestinal lumen
- B. In the lamina propria
- C. In vesicles of enterocytes
- D. In all of the above
Correct Answer: D
Rationale: IgA can be found in the intestinal lumen, lamina propria, and vesicles of enterocytes. IgA is produced by plasma cells in the lamina propria and transported across the epithelial cells into the intestinal lumen where it provides mucosal immunity. It can also be found in vesicles of enterocytes before secretion. Therefore, the correct answer is D as IgA is present in all of the mentioned locations. Choices A, B, and C are incorrect individually as they only represent specific locations where IgA can be found, not all the locations where IgA is present in the gastrointestinal tract.
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Smack' is a drug obtained from the:
- A. latex of Papaver somniferum
- B. leaves of Cannabis sativa
- C. flowers of Dhatura
- D. fruits of Erythroxylum coca
Correct Answer: A
Rationale: The correct answer is A. Smack is a street name for heroin, which is derived from the latex of Papaver somniferum, commonly known as the opium poppy. The latex of this plant contains morphine and codeine, which are the main components of heroin. Cannabis sativa (B) refers to marijuana, not smack. Dhatura (C) and Erythroxylum coca (D) are sources of other drugs like scopolamine and cocaine, respectively, not heroin. Therefore, A is the correct answer as it corresponds to the actual source of smack/heroin.
Which definition is the best description of the term genotype?
- A. Basic unit of heredity; arranged on chromosome
- B. Transmission of a disease from parent to child
- C. Genetic identity of an individual not seen as outward characteristics
- D. Family tree containing genetic characteristics and disorders of that family
Correct Answer: C
Rationale: Genotype refers to the genetic makeup of an organism, which may or may not be visible through phenotypic traits.
What role do the B-complex vitamins play in wound healing?
- A. Decrease metabolism
- B. Protect protein from being used for energy
- C. Provide metabolic energy for the inflammatory process
- D. Coenzymes for fat, protein, and carbohydrate metabolism
Correct Answer: C
Rationale: B-complex vitamins support energy production, which fuels the inflammatory and reparative processes during wound healing.
A naïve lymphocyte:
- A. Does not yet express antigen receptors
- B. Is not yet considered mature
- C. Has not yet been activated by antigen
- D. Is found only in primary lymphoid tissues
Correct Answer: C
Rationale: Step-by-step rationale:
1. Naïve lymphocytes have antigen receptors but have not been activated by antigen.
2. Activation is necessary for their differentiation into effector cells.
3. Naïve lymphocytes are considered mature as they have completed development.
4. They circulate in secondary lymphoid tissues, not just primary lymphoid tissues.
Summary:
Choice C is correct because naïve lymphocytes have antigen receptors but have not been activated by antigen. Choices A, B, and D are incorrect because naïve lymphocytes do express antigen receptors, are considered mature, and can be found in both primary and secondary lymphoid tissues.
Which antibody is transported across the placenta?
- A. IgA
- B. IgM
- C. IgG
- D. IgE
Correct Answer: C
Rationale: The correct answer is C: IgG. IgG is the only antibody that can be transported across the placenta from the mother to the fetus, providing passive immunity to the newborn. This transfer of IgG occurs through the neonatal Fc receptor (FcRn) present in the placenta. IgA is primarily found in mucosal secretions, IgM is too large to cross the placenta, and IgE is involved in allergic reactions and parasitic infections, not placental transfer. Therefore, IgG is the only antibody capable of crossing the placenta and providing immune protection to the fetus.