Nokea
Cells that contain a nucleus are __________ cells.
- A. prokaryotic
- B. eukaryotic
- C. anucleate
- D. haploid
Correct Answer: B
Rationale: The correct answer is B: eukaryotic. Eukaryotic cells have a well-defined nucleus that encloses the genetic material. The nucleus is a distinguishing feature of eukaryotic cells, separating them from prokaryotic cells (choice A) which lack a nucleus. Anucleate cells (choice C) are cells that do not have a nucleus at all. Haploid cells (choice D) contain a single set of chromosomes, but this does not necessarily imply the presence of a nucleus. Therefore, the presence of a nucleus is what categorizes cells as eukaryotic.
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A 10 year old child was subjected to Mantoux test (with tuberculin). 48 hours later a papule up to 8 mm in diameter appeared on the site of tuberculin injection. What type of hyperesponsiveness reaction has developed after tuberculin injection?
- A. Hyperresponsiveness reaction type IV
- B. Reaction of Arthus phenomenon type
- C. Reaction of serum sickness type
- D. Atopic reaction
Correct Answer: A
Rationale: The correct answer is A: Hyperresponsiveness reaction type IV. This type of reaction, also known as delayed-type hypersensitivity, is characterized by the activation of T lymphocytes and macrophages, leading to inflammation at the site of antigen exposure. In the case of the Mantoux test, the appearance of a papule 48 hours later indicates a delayed hypersensitivity reaction mediated by T cells.
Choice B: Reaction of Arthus phenomenon type is incorrect as this type of reaction involves immune complexes forming in the blood vessels leading to tissue damage, which is not the mechanism seen in the Mantoux test reaction.
Choice C: Reaction of serum sickness type is incorrect as this type of reaction involves the formation of immune complexes in the blood leading to systemic symptoms like fever, rash, and joint pain, which is not typically seen in the Mantoux test reaction.
Choice D: Atopic reaction is incorrect as atopic reactions involve IgE antibodies and mast cell degranulation, which are not the mechanisms
For cultivation of Brucella, pure cultures should be incubated in CO2 enriched atmosphere. What type of breathing is typical for Brucella?
- A. Capnophilic
- B. Facultative anaerobic
- C. Obligate anaerobic
- D. Obligate aerobic
Correct Answer: A
Rationale: The correct answer is A: Capnophilic. Brucella requires a CO2 enriched atmosphere for cultivation, making it capnophilic. This is because Brucella is a microaerophilic bacterium that thrives in low oxygen conditions and elevated CO2 levels. Choice B (Facultative anaerobic) and D (Obligate aerobic) are incorrect as Brucella does not grow well under aerobic conditions. Choice C (Obligate anaerobic) is also incorrect as Brucella can grow in the presence of oxygen, although it prefers low oxygen environments.
There are __________ known forms of gastroenteritis caused by Escherichia coli.
- A. two
- B. three
- C. four
- D. five
Correct Answer: D
Rationale: The correct answer is D: five. Escherichia coli can cause enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. coli (EHEC), enteroaggregative E. coli (EAEC), and diffusely adherent E. coli (DAEC). Each form has distinct characteristics and pathogenesis. Therefore, the other choices (A, B, C) are incorrect because they do not accurately represent the number of known forms of gastroenteritis caused by Escherichia coli.
For prevention of tuberculosis is used
- A. specific anti-tuberculosis serum
- B. BCG
- C. DTP
- D. PPD
Correct Answer: B
Rationale: The correct answer is B: BCG. Bacille Calmette-Guérin (BCG) vaccine is used for the prevention of tuberculosis. BCG is a live attenuated strain of Mycobacterium bovis that helps the immune system recognize and fight off tuberculosis bacteria. Specific anti-tuberculosis serum (A) is not used for prevention but for treatment. DTP (C) stands for diphtheria, tetanus, and pertussis vaccine, not specific for tuberculosis prevention. PPD (D) is a tuberculin skin test used for diagnosis, not prevention. Thus, BCG is the correct choice for tuberculosis prevention.
For isolating Rickettsia, the sample is investigated via:
- A. Skin-allergy tests
- B. Serological methods for proving Ab
- C. Chick embryos, cell cultures, and lab animals
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C because Rickettsia requires living cells for growth and replication. Chick embryos, cell cultures, and lab animals provide a suitable environment for Rickettsia isolation. Skin-allergy tests (A) and serological methods for proving antibodies (B) are not directly used for isolating Rickettsia as they do not support the growth of the bacteria. "None of the above" (D) is incorrect as option C involves the appropriate methods for isolating Rickettsia.