Nokea
All is true for bacterial spores EXCEPT:
- A. They can deform the cell or not
- B. They can be terminal, subterminal and central
- C. They are used for cell division
- D. They are formed for 6-8h
Correct Answer: C
Rationale: The correct answer is C. Bacterial spores are NOT used for cell division. Bacterial spores are dormant, resistant forms of bacteria that are formed in response to harsh environmental conditions. They are not involved in cell division but rather serve as a survival mechanism for the bacteria.
A: They can deform the cell or not - This is true. Bacterial spores can deform the cell or not depending on the conditions.
B: They can be terminal, subterminal, and central - This is true. Bacterial spores can be located at different positions within the bacterial cell.
D: They are formed for 6-8h - This is incorrect. The formation of bacterial spores can take variable time periods depending on the species and environmental conditions.
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The bacteria that causes whooping cough is:
- A. Bordetella pertussis
- B. Haemophilus influenzae
- C. Pseudomonas aeruginosa
- D. Streptococcus pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Bordetella pertussis. Whooping cough is caused by this bacteria, which specifically infects the respiratory tract. Bordetella pertussis produces toxins that lead to the characteristic symptoms of the disease. Haemophilus influenzae, Pseudomonas aeruginosa, and Streptococcus pneumoniae are not the causative agents of whooping cough. Haemophilus influenzae can cause respiratory infections, Pseudomonas aeruginosa is associated with hospital-acquired infections, and Streptococcus pneumoniae is a common cause of pneumonia and other respiratory infections, but none of these bacteria are responsible for whooping cough.
Which bacteria can survive in both aerobic and anaerobic conditions?
- A. Facultative anaerobes
- B. Obligate aerobes
- C. Obligate anaerobes
- D. Microaerophiles
Correct Answer: A
Rationale: The correct answer is A: Facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic conditions because they have the metabolic flexibility to switch between utilizing oxygen for respiration in aerobic conditions and using fermentation in anaerobic conditions. Obligate aerobes (B) require oxygen for survival, obligate anaerobes (C) cannot survive in the presence of oxygen, and microaerophiles (D) require low levels of oxygen to grow effectively. Therefore, the ability of facultative anaerobes to adapt to varying oxygen levels makes them the correct choice for this question.
Which bacteria are known for their ability to fix nitrogen?
- A. Bacillus cereus
- B. Azotobacter species
- C. Clostridium botulinum
- D. Escherichia coli
Correct Answer: B
Rationale: The correct answer is B: Azotobacter species. Azotobacter are known for their ability to fix nitrogen through the process of nitrogen fixation, converting atmospheric nitrogen into a form that plants can use. Bacillus cereus is not known for nitrogen fixation. Clostridium botulinum is a bacterium that causes botulism and does not fix nitrogen. Escherichia coli is a common gut bacterium but does not have the ability to fix nitrogen. Thus, Azotobacter species is the correct choice based on its unique ability to fix nitrogen.
The binomial system of nomenclature was originally developed by
- A. Pasteur
- B. Linnaeus
- C. Martini
- D. Jenner
Correct Answer: B
Rationale: The correct answer is B: Linnaeus. Linnaeus developed the binomial system of nomenclature in the 18th century. He introduced the use of a two-part naming system consisting of a genus name and a species name, known as binomial nomenclature. This system helps in organizing and categorizing living organisms systematically. Pasteur (choice A) is known for his contributions to microbiology, not nomenclature. Martini (choice C) and Jenner (choice D) are not associated with the development of the binomial system of nomenclature.
After continuous treatment with antibiotics a patient got symptoms of stomatitis. Examination of specimens of oral mucous membrane revealed some oval polymorphous Gram-positive microorganisms arranged in clusters. What microorganism may be the cause of such manifestations?
- A. С.albicans
- B. C.perfringens
- C. S.aureus
- D. S.pyogenes
Correct Answer: C
Rationale: The correct answer is C: S.aureus. Stomatitis is commonly caused by S.aureus due to its ability to form clusters of oval polymorphous Gram-positive microorganisms. S.aureus is known to colonize the oral mucous membrane and can cause infections, especially after prolonged antibiotic use.
Explanation for other choices:
A: С.albicans - Candida albicans is a fungus commonly associated with oral thrush, not typically causing stomatitis.
B: C.perfringens - Clostridium perfringens is a bacterium associated with food poisoning and gas gangrene, not commonly causing stomatitis.
D: S.pyogenes - Streptococcus pyogenes is known to cause strep throat and skin infections, but not typically associated with stomatitis.