Nokea
The function of beta-lactamase in bacteria is to:
- A. Break down antibiotics like penicillin
- B. Enhance protein synthesis
- C. Facilitate DNA replication
- D. Transport nutrients
Correct Answer: A
Rationale: The correct answer is A: Break down antibiotics like penicillin. Beta-lactamase is an enzyme produced by bacteria to inactivate beta-lactam antibiotics like penicillin by breaking the beta-lactam ring. This mechanism helps bacteria resist the antibiotic's effects. The other choices are incorrect because beta-lactamase does not enhance protein synthesis, facilitate DNA replication, or transport nutrients. It specifically targets and deactivates beta-lactam antibiotics, making choice A the most appropriate answer.
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Acute febrile pharyngitis and pharyngoconjunctival fever are often the clinical presentation of which viral infection:
- A. VZV
- B. Measles virus
- C. Rubella virus
- D. Adenovirus
Correct Answer: D
Rationale: The correct answer is D: Adenovirus. Adenovirus commonly causes acute febrile pharyngitis and pharyngoconjunctival fever. Adenovirus is known to cause respiratory infections and can present with symptoms such as sore throat, fever, and conjunctivitis. VZV (Varicella-Zoster Virus) causes chickenpox and shingles, not these specific symptoms. Measles virus causes a systemic illness with characteristic rash, not typically pharyngitis. Rubella virus causes a mild febrile illness with rash, but not pharyngitis. Therefore, based on the clinical presentation described, adenovirus is the most likely cause.
Which of the following diseases is transmitted via aerosols?
- A. Psittacosis
- B. Shigellosis
- C. Leptospirosis
- D. Giardiasis
Correct Answer: A
Rationale: The correct answer is A: Psittacosis. This disease is transmitted via aerosols containing dried bird droppings or respiratory secretions from infected birds. When these aerosols are inhaled, the bacteria causing psittacosis enter the respiratory system and infect the individual.
- B: Shigellosis is transmitted through contaminated food or water, not via aerosols.
- C: Leptospirosis is transmitted through contact with water, soil, or food contaminated with the urine of infected animals, not via aerosols.
- D: Giardiasis is transmitted through ingesting contaminated food or water, not via aerosols.
Therefore, Psittacosis is the only disease in the list that is transmitted via aerosols, making it the correct answer.
Which of the following food media can be used for cultivation of Streptococcus pneumoniae:
- A. Blood agar
- B. MacConkey agar
- C. Peptone water
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Blood agar. Streptococcus pneumoniae is a fastidious bacterium that requires enriched media for growth. Blood agar provides the necessary nutrients and growth factors for the cultivation of S. pneumoniae, such as blood proteins and hemin. MacConkey agar (B) is selective for gram-negative bacteria and would not support the growth of S. pneumoniae. Peptone water (C) is a liquid medium that lacks the necessary nutrients for the growth of S. pneumoniae. Choice D is incorrect as blood agar is a suitable medium for cultivating S. pneumoniae.
A disease that is generally present in a given population is:
- A. pandemic
- B. epidemic
- C. sporadic
- D. endemic
Correct Answer: D
Rationale: The correct answer is D: endemic. Endemic refers to a disease that is consistently present in a particular population or region at a relatively stable level. This means the disease is always present in that specific area. Pandemic (A) refers to a disease that spreads across multiple countries or continents. Epidemic (B) refers to a sudden increase in the number of cases of a disease above what is normally expected in that population. Sporadic (C) refers to occasional cases of a disease occurring irregularly in a population. Therefore, the correct choice is D as it specifically describes a disease that is generally present in a given population.
Cholera is a serious gastrointestinal illness caused by bacteria of the genus:
- A. Escherichia
- B. Salmonella
- C. Vibrio
- D. Acinetobacter
Correct Answer: C
Rationale: The correct answer is C: Vibrio. Cholera is caused by Vibrio cholerae bacteria. These bacteria produce a toxin that causes severe diarrhea and dehydration. Escherichia (choice A) and Salmonella (choice B) are known for causing other types of gastrointestinal infections but not cholera. Acinetobacter (choice D) typically causes respiratory infections, not gastrointestinal illnesses like cholera. Therefore, the correct choice is Vibrio as it is specifically associated with cholera.