The complex of non-specific innate defense factors acting against number of infectious agents is known as:
- A. Adaptive immunity
- B. Immune memory
- C. Antibody
- D. Innate immunity (natural resistance)
Correct Answer: D
Rationale: The correct answer is D: Innate immunity (natural resistance). Innate immunity refers to the non-specific defense mechanisms that act against a variety of infectious agents. This includes physical barriers like skin and mucous membranes, as well as cellular components like phagocytes and natural killer cells. Adaptive immunity (A) is specific and involves the production of antibodies and immune memory (B), which are not part of the initial non-specific response. Antibodies (C) are part of the adaptive immune response and are produced in response to specific pathogens, not part of the non-specific innate defense factors.
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Gram-negative rods producing blue-green pigment and a fruity odor were isolated from a wound infection. What is the causative agent?
- A. Pseudomonas aeruginosa
- B. Proteus mirabilis
- C. Klebsiella pneumoniae
- D. Escherichia coli
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas aeruginosa. P. aeruginosa is known for producing a blue-green pigment called pyocyanin, which gives a characteristic color to the colonies. The fruity odor is due to the production of a compound called 2-aminoacetophenone by P. aeruginosa. These features are classic for P. aeruginosa and help differentiate it from other Gram-negative rods. Proteus mirabilis (B) typically does not produce blue-green pigment or fruity odor. Klebsiella pneumoniae (C) and Escherichia coli (D) also do not exhibit these specific characteristics associated with P. aeruginosa.
Patients planned for treatment with monoclonal antibodies are tested for:
- A. HBV
- B. HCV
- C. M. tuberculosis
- D. All are correct
Correct Answer: D
Rationale: The correct answer is D: All are correct. Patients planned for treatment with monoclonal antibodies should be tested for HBV, HCV, and M. tuberculosis due to the risk of reactivation of these infections during treatment. HBV and HCV reactivation can lead to severe liver damage, while M. tuberculosis reactivation can cause serious respiratory complications. Testing for all three infections helps in identifying and managing any pre-existing infections to ensure patient safety during monoclonal antibody treatment. Choices A, B, and C are incorrect because each of these infections presents specific risks that need to be assessed before initiating monoclonal antibody therapy.
The organisms to be identified have a nucleus surrounded by a nuclear membrane. Genetic material is concentrated predominantly in the chromosomes which consist of DNA strands and protein molecules. These cells divide mitotically. Identify these organisms:
- A. Eukaryotes
- B. Bacteriophages
- C. Prokaryotes
- D. Viruses
Correct Answer: A
Rationale: Step-by-step rationale:
1. The presence of a nucleus with a nuclear membrane indicates eukaryotic cells.
2. Eukaryotes have genetic material in chromosomes made of DNA and proteins.
3. Mitotic division is characteristic of eukaryotic cells.
4. Therefore, the organisms described are eukaryotes.
Summary:
- Bacteriophages (B) are viruses that infect bacteria.
- Prokaryotes (C) lack a nucleus and their genetic material is not organized into chromosomes.
- Viruses (D) are not considered living organisms and do not have a nucleus or chromosomes.
How is viral multiplication detected in cell culture?
- A. by the presence of a specific cytopathic effect
- B. by using an immunofluorescence detection method
- C. the characteristic type of viral colonies
- D. A and B both
Correct Answer: D
Rationale: The correct answer is D because viral multiplication in cell culture can be detected by observing a specific cytopathic effect (A) caused by viral infection in cells and by using an immunofluorescence detection method (B) to visualize viral antigens within the cells. Choice C, the characteristic type of viral colonies, is incorrect as viral multiplication is not typically detected by observing viral colonies in cell culture. Option D is the correct choice as both A and B methods are commonly used to detect viral multiplication in cell culture.
Bacterial spores are used for:
- A. Protection against phagocytosis
- B. Reproduction
- C. Survival
- D. Nutrient storage
Correct Answer: C
Rationale: The correct answer is C: Survival. Bacterial spores are specialized structures that bacteria form to survive harsh conditions such as extreme temperatures or lack of nutrients. Spores are not used for protection against phagocytosis (A) as they are dormant structures and not actively involved in defense mechanisms. They are not for reproduction (B) as spores are a form of bacterial reproduction but not the primary purpose of spore formation. Spores do not serve as nutrient storage (D) as they are mainly used for survival during unfavorable conditions.