Nokea
Streptococcus pyogenes releases:
- A. Enterotoxin
- B. Streptolysin
- C. Staphylocoagulase
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: Streptolysin. Streptolysin is a toxin released by Streptococcus pyogenes that causes lysis of red blood cells and contributes to the pathogenicity of the bacteria. Enterotoxin (Choice A) is typically produced by Staphylococcus aureus, not Streptococcus pyogenes. Staphylocoagulase (Choice C) is an enzyme produced by Staphylococcus aureus to promote blood clot formation and is not associated with Streptococcus pyogenes. Therefore, the correct answer is B as Streptolysin is the toxin released by Streptococcus pyogenes.
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Which of the following viruses does not belong to family Paramyxoviridae:
- A. Measles virus
- B. Respiratory syncytial virus
- C. Mumps virus
- D. Rubella virus
Correct Answer: D
Rationale: The correct answer is D: Rubella virus. Rubella virus does not belong to the family Paramyxoviridae because it belongs to the Togaviridae family. The other choices, A (Measles virus), B (Respiratory syncytial virus), and C (Mumps virus) are all members of the Paramyxoviridae family. This classification is based on the genetic and structural characteristics of the viruses. Rubella virus is distinct in its genetic composition and replication cycle compared to the Paramyxoviridae family, making it the correct choice.
Enzymes used in ELISA are those except:
- A. Î’-lactamase
- B. Alkaline phosphatase
- C. Horseradish peroxidase
- D. Î’- galactosidase
Correct Answer: A
Rationale: The correct answer is A: Β-lactamase. In ELISA, enzymes like alkaline phosphatase, horseradish peroxidase, and Β-galactosidase are commonly used as labels to detect the presence of specific molecules. Β-lactamase is not typically used in ELISA as it is an enzyme used to hydrolyze β-lactam antibiotics. Therefore, it does not serve the purpose of detecting specific molecules in ELISA. Alkaline phosphatase, horseradish peroxidase, and Β-galactosidase are preferred enzymes in ELISA due to their ability to produce a detectable signal when bound to specific molecules.
Researchers of a bacteriological laboratory examine tinned meat for botulinic toxin. For this purpose a group of mice was injected with an extract of the material under examination and antitoxic antibotulinic serum of A, B, E types. A control group of mice was injected with the same extract but without antibotulinic serum. What serological reaction was applied?
- A. Neutralization
- B. Precipitation
- C. Complement binding
- D. Double immune diffusion
Correct Answer: A
Rationale: The correct answer is A: Neutralization. In this experiment, the researchers used antitoxic antibotulinic serum of different types to neutralize the botulinic toxin in tinned meat extract injected into mice. Neutralization is the process of rendering a toxin harmless by combining it with specific antibodies. The purpose of injecting the antitoxic serum was to neutralize the toxin and prevent it from causing harm to the mice. This serological reaction of neutralization directly aligns with the objective of the experiment.
Summary of other choices:
B: Precipitation - Precipitation involves the formation of a visible insoluble complex when an antigen reacts with its corresponding antibody. This process was not described in the scenario.
C: Complement binding - Complement binding involves the activation of the complement system by antigen-antibody complexes. This was not the main focus of the experiment described.
D: Double immune diffusion - This technique is used to detect the presence of specific antigens or antibodies
Examination of duodenal contents revealed some pyriform protozoa with twin nuclei and four pairs of flagella. There were two supporting filaments between the nuclei and a suctorial disc on the ventral side. What representative of protozoa was revealed in this patient?
- A. Lamblia
- B. Toxoplasma
- C. Leishmania
- D. Intestinal trichomonad
Correct Answer: A
Rationale: Rationale for Correct Answer A (Lamblia):
1. Pyriform protozoa with twin nuclei, four pairs of flagella, and a suctorial disc match the characteristics of Giardia lamblia.
2. The presence of two supporting filaments between the nuclei is a unique feature of Giardia lamblia.
3. Giardia lamblia is known to infect the duodenum and cause symptoms such as diarrhea and abdominal pain.
Summary of Incorrect Choices:
B: Toxoplasma - Toxoplasma gondii is not characterized by four pairs of flagella or supporting filaments in the nuclei.
C: Leishmania - Leishmania species do not typically have the described morphology or location in the duodenum.
D: Intestinal trichomonad - Intestinal trichomonads do not exhibit the specific features mentioned in the question, such as twin nuclei and supporting filaments.
The taxonomic resource for information on bacteria is __________.
- A. Gray's Anatomy
- B. Bergey's Manual of Systematic Bacteriology
- C. WHO Manual
- D. Darwin's Origin of Species
Correct Answer: B
Rationale: The correct answer is B: Bergey's Manual of Systematic Bacteriology. This manual is a comprehensive and authoritative resource specifically dedicated to bacterial taxonomy, classification, and identification. It provides detailed descriptions and classification schemes for bacteria, aiding in accurate identification and understanding of bacterial species. Gray's Anatomy (choice A) focuses on human anatomy, the WHO Manual (choice C) focuses on global health guidelines, and Darwin's Origin of Species (choice D) discusses evolution and natural selection, none of which are specialized taxonomic resources for bacteria.