Nokea
Polyclonal antibodies can respond to multiple antigens:
- A. TRUE
- B. FALSE
- C. All of the above
- D. None of the above
Correct Answer: A
Rationale: Polyclonal antibodies are produced by different B cells, each recognizing a different epitope on an antigen. Therefore, they can respond to multiple antigens. This diversity in recognition allows polyclonal antibodies to bind to various targets, making option A true. Options B, C, and D are incorrect as they do not accurately reflect the nature of polyclonal antibodies' ability to recognize multiple antigens.
You may also like to solve these questions
A child is ill with diphtheria. A smear of the affected mucous membrane revealed blue rods with thickenings at the poles. What staining method was used?
- A. Neisser
- B. Gram
- C. Ziehl-Neelsen
- D. Loeffler
Correct Answer: A
Rationale: The correct answer is A: Neisser staining method. Neisser staining method is used to stain diphtheria bacilli, which appear as blue rods with thickenings at the poles. The rationale is that Neisser staining specifically targets and highlights the characteristics of the diphtheria bacilli.
Incorrect choices:
B: Gram staining is not specific for diphtheria bacilli and does not show the characteristic blue rods with thickenings at the poles.
C: Ziehl-Neelsen staining is used for acid-fast bacteria like Mycobacterium tuberculosis, not for diphtheria bacilli.
D: Loeffler staining is used for diphtheria bacilli but does not produce blue rods with thickenings at the poles as seen in this case.
On a certain territory mass death of rodents was registered. It was suspected that their death might have been caused by plague. What serological reaction should be applied for quick identification of antigen of the causative agent of this epizooty?
- A. Precipitation
- B. Agglutination
- C. Passive hemagglutination
- D. Complement binding
Correct Answer: B
Rationale: The correct answer is B: Agglutination. During a suspected plague outbreak, agglutination testing is used to quickly identify the antigen of the causative agent. In this test, specific antibodies are added to a sample containing the suspected antigen. If the antigen is present, it will clump together (agglutinate) with the antibodies, indicating a positive result. This method is rapid and efficient for identifying the presence of the plague-causing agent.
Choice A: Precipitation involves the formation of a visible precipitate when antigen and antibody react, but it is not as quick or specific as agglutination for identifying the antigen in this scenario.
Choice C: Passive hemagglutination is a variation of agglutination that uses red blood cells as carriers for antigens or antibodies. While it can be useful in certain situations, it is not typically the first choice for rapid identification of plague antigen.
Choice D: Complement binding is a different type of
As an example of specific human parasites one can name Plasmodium falciparum, human pinworm and some others. The source of parasite invasion is always a human. Such specific human parasites cause the diseases that are called:
- A. Anthroponoses
- B. Zoonoses
- C. Anthropozoonoses
- D. Infections
Correct Answer: A
Rationale: The correct answer is A: Anthroponoses. This term refers to diseases caused by specific human parasites that are transmitted directly from human to human. In this case, the source of parasite invasion is always a human host. This term specifically describes diseases caused by parasites that exclusively infect humans.
Choice B: Zoonoses refers to diseases that can be transmitted from animals to humans. Choice C: Anthropozoonoses is a combination of zoonoses and anthroponoses, which is not applicable in this scenario. Choice D: Infections is a general term that does not specify the source or type of parasite causing the disease.
A patient with severe abdominal pain and vomiting had a blood culture that revealed Gram-negative rods producing gas. What is the most likely causative agent?
- A. Escherichia coli
- B. Salmonella enteritidis
- C. Clostridium perfringens
- D. Campylobacter jejuni
Correct Answer: B
Rationale: The correct answer is B: Salmonella enteritidis. In this case, the presence of Gram-negative rods producing gas in the blood culture indicates a likelihood of Salmonella infection, as it is a common cause of severe abdominal pain, vomiting, and gas production. Salmonella enteritidis is a known pathogen that can cause gastroenteritis and systemic infections. Escherichia coli (choice A) can also cause similar symptoms, but it is less likely to produce gas in blood culture. Clostridium perfringens (choice C) typically causes food poisoning with rapid onset and less likely to be isolated from blood cultures. Campylobacter jejuni (choice D) is associated with gastroenteritis but is less likely to cause systemic infections with gas-producing Gram-negative rods in blood culture.
N. Meningitidis grows on
- A. Levine agar
- B. Lowenstein-Jensen agar
- C. TCBS agar
- D. Chocolate agar
Correct Answer: D
Rationale: The correct answer is D: Chocolate agar. Neisseria meningitidis is a fastidious organism that requires enriched media for growth. Chocolate agar contains heat-treated blood that provides essential nutrients for the growth of N. meningitidis. The other choices, A: Levine agar, B: Lowenstein-Jensen agar, and C: TCBS agar, do not provide the specific nutrients required for the growth of N. meningitidis. Therefore, only choice D, Chocolate agar, supports the growth of N. meningitidis due to its enriched composition.