Bacteria that require oxygen for survival are called:
- A. Obligate anaerobes
- B. Facultative anaerobes
- C. Obligate aerobes
- D. Aerotolerant anaerobes
Correct Answer: C
Rationale: The correct answer is C: Obligate aerobes. These bacteria require oxygen for their survival and growth. They utilize oxygen in their metabolic processes and cannot survive in the absence of oxygen. Choice A, obligate anaerobes, cannot survive in the presence of oxygen. Choice B, facultative anaerobes, can switch between aerobic and anaerobic metabolism based on oxygen availability. Choice D, aerotolerant anaerobes, can tolerate the presence of oxygen but do not require it for their growth. Therefore, the most appropriate term for bacteria that require oxygen for survival is obligate aerobes.
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Bacillary dysentery is also called:
- A. salmonellosis
- B. shigellosis
- C. typhoid fever
- D. campylobacteriosis
Correct Answer: B
Rationale: Bacillary dysentery is caused by the bacterium Shigella, hence it is also known as shigellosis. Shigella is the primary pathogen responsible for this infectious disease, leading to severe diarrhea with blood and mucus. Salmonellosis (A) is caused by Salmonella bacteria, not Shigella. Typhoid fever (C) is caused by Salmonella typhi, not Shigella. Campylobacteriosis (D) is caused by Campylobacter bacteria, not Shigella. Therefore, the correct answer is B because Shigella is the specific bacterium associated with bacillary dysentery.
For treatment of Anthrax are used
- A. Penicillins, tetracyclins, macrolides
- B. anti-anthrax gamma-globulins
- C. anti-anthrax immune-serum
- D. all of the above
Correct Answer: D
Rationale: The correct answer is D because the treatment for Anthrax involves using antibiotics such as penicillins, tetracyclines, and macrolides to target the bacteria. Anti-anthrax gamma-globulins and immune-serum are used to provide passive immunity, but they are not the primary treatment. Therefore, options A, B, and C are incorrect as they do not encompass all the necessary components for treating Anthrax. Overall, using a combination of antibiotics and immune-based treatments like gamma-globulins and immune-serum provides a comprehensive approach to managing Anthrax infection.
The tertiary stage of syphilis is usually manifested as:
- A. Syphilitic granulomas (gummas)
- B. Purulent exudation from the urethra
- C. Non-tender chancre (ulcus durum)
- D. Diffuse maculopapular rash
Correct Answer: A
Rationale: The correct answer is A: Syphilitic granulomas (gummas). In the tertiary stage of syphilis, gummas, which are soft, tumor-like growths, can develop in various organs such as the skin, bones, liver, and brain. This stage typically occurs years after the initial infection and can lead to serious complications if left untreated. Purulent exudation from the urethra (B) is not specific to syphilis and may indicate other infections. Non-tender chancre (C) is characteristic of the primary stage of syphilis, not the tertiary stage. Diffuse maculopapular rash (D) is more commonly seen in the secondary stage of syphilis.
Which of the following has a higher resistance to environmental stresses than the others?
- A. Bacterial endospores
- B. Fungal spores
- C. Enveloped viruses
- D. Vegetative bacterial cells
Correct Answer: A
Rationale: The correct answer is A: Bacterial endospores. Bacterial endospores have a higher resistance to environmental stresses due to their unique structure, which includes a tough outer layer that protects the spore from harsh conditions such as heat, chemicals, and radiation. This protective layer allows endospores to remain dormant and survive in unfavorable environments until conditions improve.
Summary:
B: Fungal spores - While fungal spores can also survive in harsh conditions, they are generally not as resistant as bacterial endospores due to differences in their protective structures.
C: Enveloped viruses - Enveloped viruses are susceptible to environmental stresses as their lipid envelope can easily be damaged by heat, chemicals, and other factors.
D: Vegetative bacterial cells - Vegetative bacterial cells are more susceptible to environmental stresses compared to endospores, as they do not have the same level of protective mechanisms to survive in unfavorable conditions.
Which of the following bacteria is known for producing a neurotoxin that causes paralysis?
- A. Clostridium botulinum
- B. Clostridium perfringens
- C. Escherichia coli
- D. Staphylococcus aureus
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum. This bacterium produces the botulinum neurotoxin, which causes paralysis by blocking the release of acetylcholine at neuromuscular junctions. Clostridium perfringens causes gas gangrene, not paralysis. Escherichia coli is associated with gastrointestinal infections, not paralysis. Staphylococcus aureus produces enterotoxins causing food poisoning, not paralysis. Therefore, Clostridium botulinum is the correct choice based on its well-known association with paralysis due to botulinum neurotoxin production.