The lipophilization is:
- A. Dehydration of the cell under deep vacuum in frozen state (-20.-30 degrees)
- B. Hydration of frozen cells
- C. Enrichment of the cells with proteins under deep vacuum
- D. Removing the protein content of the cell under deep vacuum
Correct Answer: A
Rationale: The correct answer is A because lipophilization is the process of removing water from cells under deep vacuum in a frozen state. Dehydration of the cell at a low temperature helps to preserve the cellular structure and components. Choice B is incorrect as hydration does the opposite of what lipophilization aims to achieve. Choice C is incorrect as lipophilization does not involve enriching cells with proteins. Choice D is incorrect as lipophilization does not involve removing protein content from cells.
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Which of the following organisms belongs in the group I category?
- A. Francisella tularensis
- B. Clostridium difficile
- C. Helicobacter pylori
- D. Bacillus anthracis
Correct Answer: C
Rationale: The correct answer is C: Helicobacter pylori. Group I organisms are classified based on their low infectious doses and potential for bioterrorism. H. pylori is known to cause gastric ulcers and is categorized as a Group I organism due to its ability to cause disease at low doses.
A: Francisella tularensis is a Group A bioterrorism agent, not Group I.
B: Clostridium difficile is not typically classified as a Group I organism.
D: Bacillus anthracis is a Group A bioterrorism agent, not Group I.
Conidiospores that bud off from a vase-shaped spore-bearing cell are referred to as:
- A. arthrospores
- B. porospores
- C. phialospores
- D. blastospores
Correct Answer: C
Rationale: The correct answer is C: phialospores. Phialospores are conidiospores that bud off from a vase-shaped spore-bearing cell called a phialide. This structure is characteristic of fungi in the genus Penicillium. Arthrospores (A) are formed by the fragmentation of hyphae, porospores (B) are not a recognized term in mycology, and blastospores (D) are produced by budding from yeast cells. Therefore, C is the correct choice based on the specific description provided in the question.
Which of the following bacteria is commonly associated with food poisoning?
- A. Salmonella enterica
- B. Clostridium botulinum
- C. Escherichia coli
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D: All of the above. Salmonella enterica, Clostridium botulinum, and Escherichia coli are all commonly associated with food poisoning. Salmonella causes symptoms like diarrhea, vomiting, and abdominal cramps. Clostridium botulinum produces a toxin that leads to symptoms like muscle weakness and paralysis. Escherichia coli can cause symptoms like severe stomach cramps, diarrhea (often bloody), and vomiting. Therefore, all three bacteria are known to cause food poisoning. The other choices are incorrect because each of the bacteria listed is associated with food poisoning.
All statements of viral neutralization reaction are true except:
- A. A key component of the reaction is the complement system involvement
- B. Specific virus neutralising antibodies block the viral ability to infect cells
- C. The antibodies are titrated and two serum samples are required
- D. It is also used to identify newly isolated virus
Correct Answer: A
Rationale: Rationale:
A: Incorrect - The complement system is not directly involved in the viral neutralization reaction.
B: Correct - Specific antibodies neutralize viruses by blocking their ability to infect cells.
C: Incorrect - Antibodies are titrated, but only one serum sample is required for neutralization testing.
D: Incorrect - Viral neutralization is primarily used to measure antibody response, not to identify newly isolated viruses.
The ability of Clostridium tetani to produce exotoxins is encoded by?
- A. genes with chromosomal location
- B. clostridium tetani is not capable of producing exotoxins, it has only endotoxin activity
- C. genes with plasmid location
- D. chromosomal and plasmid location
Correct Answer: C
Rationale: The correct answer is C: genes with plasmid location. Clostridium tetani produces exotoxins through genes located on plasmids. Plasmids are extrachromosomal genetic elements that carry additional genes. These genes encode for the production of exotoxins in Clostridium tetani. Choices A, B, and D are incorrect because Clostridium tetani does produce exotoxins, it does not have only endotoxin activity, and the genes responsible for exotoxin production are located on plasmids, not solely on the chromosome or both chromosome and plasmid.