Nokea
Which of the following microorganisms can be cultured only in the footpads of mice or a species of armadillo?
- A. Mycobacterium tuberculosis
- B. Mycobacterium leprae
- C. Neisseria gonorrhoeae
- D. Mycoplasma
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium leprae. This microorganism can only be cultured in the footpads of mice or a species of armadillo due to its specific growth requirements. Mycobacterium tuberculosis (choice A) can be cultured in various culture media in the laboratory. Neisseria gonorrhoeae (choice C) can be cultured on selective media like Thayer-Martin agar. Mycoplasma (choice D) can be cultured in cell cultures or specialized media. Therefore, the unique growth pattern of Mycobacterium leprae makes it the correct answer.
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N. Meningitidis grows on
- A. Levine agar
- B. Lowenstein-Jensen agar
- C. TCBS agar
- D. Chocolate agar
Correct Answer: D
Rationale: The correct answer is D: Chocolate agar. Neisseria meningitidis is a fastidious organism that requires enriched media for growth. Chocolate agar contains heat-treated blood that provides essential nutrients for the growth of N. meningitidis. The other choices, A: Levine agar, B: Lowenstein-Jensen agar, and C: TCBS agar, do not provide the specific nutrients required for the growth of N. meningitidis. Therefore, only choice D, Chocolate agar, supports the growth of N. meningitidis due to its enriched composition.
Stroma is a component of:
- A. chloroplasts
- B. mitochondria
- C. mitochondria
- D. lysosomes
Correct Answer: B
Rationale: The correct answer is B: mitochondria. Stroma is a component of chloroplasts, not mitochondria. Lysosomes contain hydrolytic enzymes, not stroma. Mitochondria have an inner and outer membrane structure, with the matrix containing the stroma where important metabolic processes occur. This is where the Krebs cycle and oxidative phosphorylation take place. Stroma in chloroplasts is where photosynthesis occurs. So, the correct answer is B because stroma is a component of mitochondria, where crucial energy production processes happen.
As an example of specific human parasites one can name Plasmodium falciparum, human pinworm and some others. The source of parasite invasion is always a human. Such specific human parasites cause the diseases that are called:
- A. Anthroponoses
- B. Zoonoses
- C. Anthropozoonoses
- D. Infections
Correct Answer: A
Rationale: The correct answer is A: Anthroponoses. This term refers to diseases caused by specific human parasites that are transmitted directly from human to human. In this case, the source of parasite invasion is always a human host. This term specifically describes diseases caused by parasites that exclusively infect humans.
Choice B: Zoonoses refers to diseases that can be transmitted from animals to humans. Choice C: Anthropozoonoses is a combination of zoonoses and anthroponoses, which is not applicable in this scenario. Choice D: Infections is a general term that does not specify the source or type of parasite causing the disease.
Which of the following bacteria should be handled in a Biosafety Level 2 facility?
- A. Micrococcus luteus
- B. Bacillus subtilis
- C. Salmonella
- D. Staphylococcus epidermidis
Correct Answer: C
Rationale: The correct answer is C: Salmonella. This bacterium should be handled in a Biosafety Level 2 facility due to its potential to cause disease in humans. Salmonella is a pathogenic bacterium that can cause foodborne illnesses and infections. Handling it in a Biosafety Level 2 facility ensures proper containment and protection of personnel.
A: Micrococcus luteus and B: Bacillus subtilis are common environmental bacteria that do not pose significant risks to human health, so they can be safely handled in lower biosafety levels.
D: Staphylococcus epidermidis is a common skin commensal bacterium that is generally not considered highly pathogenic, so it does not require Biosafety Level 2 containment.
Rotaviruses:
- A. The NSP4 nonstructural protein of rotaviruses acts in a toxic-like manner.
- B. Disease can be significant in infants and adults
- C. Cannot survive the acidic environment in the stomach
- D. Prevents the absorption of water, but do not cause a net secretion of water and loss of ions
Correct Answer: A
Rationale: The correct answer is A because the NSP4 nonstructural protein of rotaviruses indeed acts in a toxic-like manner by disrupting calcium homeostasis, leading to diarrhea. Choice B is incorrect as rotaviruses can cause significant disease in infants, but not typically in adults. Choice C is incorrect as rotaviruses are resistant to stomach acid. Choice D is incorrect as rotaviruses cause a net secretion of water and loss of ions, contributing to diarrhea.