Nokea
Which one of the following processes emerged earliest during the course of evolution?
- A. Antigen presentation
- B. Antibody production
- C. Phagocytosis
- D. Thymic education
Correct Answer: C
Rationale: The correct answer is C: Phagocytosis. Phagocytosis is a fundamental process that emerged early in evolution for cellular organisms to engulf and digest particles. This process is essential for basic survival and defense mechanisms.
A: Antigen presentation and B: Antibody production are more advanced immune responses that occur in higher organisms and require a complex immune system.
D: Thymic education is a process specific to vertebrates involving the maturation and selection of T cells, which is a more evolved mechanism compared to phagocytosis.
Therefore, phagocytosis is the earliest process among the options listed as it is essential for basic cellular survival and predates the development of advanced immune responses.
You may also like to solve these questions
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.
If HLA-DR4 is considered a 'risk' allele for disease 'X', this means:
- A. All individuals with the HLA-DR4 allele will get disease X
- B. All individuals with disease X have the HLA-DR4 allele
- C. An individual with the HLA-DR4 allele has an increased chance of developing disease X compared to other individuals
- D. All of the above are true
Correct Answer: C
Rationale: The correct answer is C because having the HLA-DR4 allele increases the likelihood of developing disease X but does not guarantee it. Choice A is incorrect because not all individuals with HLA-DR4 will get disease X. Choice B is incorrect because not all individuals with disease X have the HLA-DR4 allele. Choice D is incorrect because it falsely states that all statements are true, which is not the case.
All of the following are true with respect to IgM antibodies EXCEPT which one
- A. they fix complement
- B. they occur on the surface of lymphocytes
- C. they predominate in the primary response to antigen
- D. mediate allergic reactions
Correct Answer: D
Rationale: The correct answer is D. IgM antibodies do not mediate allergic reactions. IgE antibodies are responsible for allergic reactions. IgM antibodies fix complement, occur on the surface of lymphocytes, and predominate in the primary response to antigens. IgM is the first antibody produced in response to an infection, playing a key role in the activation of the complement system. IgM antibodies are mainly found in the blood and lymphatic system, not on the surface of lymphocytes. IgE antibodies are the primary mediators of allergic reactions by triggering the release of histamine and other inflammatory molecules.
Autoimmune diseases are associated with several susceptibility factors. Environmental factors associated with increased risk of autoimmune disease include:
- A. Infections
- B. Level of exposure to the sun
- C. Imbalance of microbiota composition
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Autoimmune diseases have complex causes, involving genetic predisposition and environmental factors. Infections can trigger autoimmune responses, sunlight exposure can influence immune function, and an imbalance in microbiota composition can lead to dysregulated immune responses. Therefore, all three factors can contribute to an increased risk of autoimmune diseases. Choices A, B, and C individually are all associated with autoimmune diseases, making option D the correct choice.
Which of the following is considered a defining characteristic of a TH2 response?
- A. Production of IgM antibodies
- B. Activation of CTL
- C. Recruitment and activation of neutrophils
- D. Production of IgE antibodies
Correct Answer: D
Rationale: The correct answer is D: Production of IgE antibodies. A TH2 response is characterized by the production of IgE antibodies, which are essential in allergic reactions. IgM antibodies (A) are produced during the primary immune response. Activation of CTL (B) is associated with a TH1 response. Neutrophils (C) are primarily involved in the innate immune response and are not specific to TH2 responses. In summary, the production of IgE antibodies is a defining characteristic of a TH2 response, distinguishing it from other immune responses.