Nokea
Which bacteria are capable of forming spores that help them survive in extreme conditions?
- A. Clostridium botulinum
- B. Bacillus anthracis
- C. Both A and B
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C, both A and B. Clostridium botulinum and Bacillus anthracis are both capable of forming spores, which are a protective mechanism that allows them to survive harsh conditions. Clostridium botulinum causes botulism and forms spores in anaerobic environments, while Bacillus anthracis causes anthrax and forms spores in aerobic environments. Therefore, both choices A and B are correct. Choice D is incorrect as it contradicts the fact that both bacteria are capable of forming spores.
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Which of the following bacteria is responsible for causing gonorrhea?
- A. Chlamydia trachomatis
- B. Neisseria gonorrhoeae
- C. Treponema pallidum
- D. Escherichia coli
Correct Answer: B
Rationale: The correct answer is B: Neisseria gonorrhoeae. This bacterium is responsible for causing gonorrhea. Neisseria gonorrhoeae is a sexually transmitted bacterium that infects the mucous membranes of the reproductive tract. It is known for causing symptoms such as painful urination and discharge. Chlamydia trachomatis (choice A) is another sexually transmitted bacterium but is not responsible for gonorrhea. Treponema pallidum (choice C) causes syphilis, not gonorrhea. Escherichia coli (choice D) is a common bacterium found in the gut and is not associated with causing gonorrhea. Therefore, Neisseria gonorrhoeae is the correct answer for this question.
Which bacteria produce exotoxins that affect the nervous system?
- A. Clostridium botulinum and Clostridium tetani
- B. Escherichia coli and Salmonella
- C. Bacillus anthracis and Listeria monocytogenes
- D. Pseudomonas aeruginosa and Staphylococcus aureus
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum and Clostridium tetani. Both bacteria produce exotoxins that affect the nervous system. Clostridium botulinum produces botulinum toxin, causing botulism, leading to muscle paralysis. Clostridium tetani produces tetanospasmin, causing tetanus, leading to muscle stiffness and spasms.
Choice B (Escherichia coli and Salmonella) are known for causing gastrointestinal infections, not specifically affecting the nervous system. Choice C (Bacillus anthracis and Listeria monocytogenes) produce toxins that primarily affect other body systems, not the nervous system. Choice D (Pseudomonas aeruginosa and Staphylococcus aureus) are associated with skin and respiratory infections, not neurological effects.
Viruses cannot multiply in:
- A. Artificial nutrient media
- B. Living cells
- C. Human embryonic cells
- D. Bacteria
Correct Answer: A
Rationale: The correct answer is A: Artificial nutrient media. Viruses are obligate intracellular parasites, meaning they require living host cells to replicate. They cannot multiply in artificial nutrient media as they lack the cellular machinery necessary for viral replication. Living cells, including human embryonic cells and bacteria, provide the required cellular environment for viruses to replicate. Therefore, options B, C, and D are incorrect as they all contain living cells that can support viral multiplication.
In which of the following GIT infections, the bacteria adhere to the intestine wall and damage the microvilli:
- A. Enteropathogenic E. Coli (EPEC)
- B. Enterohemorrhagic E. Coli (EHEC)
- C. Enterotoxigenic E Coli (ETEC)
- D. Enteroinvasive E Coli (EIEC)
Correct Answer: A
Rationale: The correct answer is A: Enteropathogenic E. Coli (EPEC). EPEC bacteria adhere to the intestine wall using a protein called intimin, leading to microvilli damage. This attachment disrupts the normal absorption function of the intestine.
Summary of why other choices are incorrect:
B: Enterohemorrhagic E. Coli (EHEC) primarily causes bloody diarrhea and does not specifically target microvilli.
C: Enterotoxigenic E. Coli (ETEC) produces toxins that lead to watery diarrhea but does not directly target microvilli.
D: Enteroinvasive E. Coli (EIEC) invades and replicates within intestinal cells, causing inflammatory diarrhea, but does not specifically damage microvilli.
The catarrhal stage of the whooping cough is characterized by:
- A. Decrease in paroxysms of coughing
- B. Subsequent respiratory infection for many months after the onset of pertussis
- C. Uncontrollable coughing followed by a high pitched 'whoop' sound
- D. Mild respiratory symptoms (mild coughing, sneezing or a runny nose)
Correct Answer: D
Rationale: The correct answer is D because the catarrhal stage of whooping cough is characterized by mild respiratory symptoms such as mild coughing, sneezing, or a runny nose. During this stage, the cough may start to worsen but is not yet severe.
A: Incorrect - Decrease in paroxysms of coughing is not seen in the catarrhal stage; it occurs later in the paroxysmal stage.
B: Incorrect - Subsequent respiratory infection for many months after the onset of pertussis is not a characteristic of the catarrhal stage.
C: Incorrect - Uncontrollable coughing followed by a high pitched 'whoop' sound is typical of the paroxysmal stage, not the catarrhal stage.