Nokea
Microscopy of dental plaque revealed unicellular organisms. Their cytoplasm had two distinct layers, barely visible core, wide pseudopodia. The patient is most likely to have:
- A. Entamoeba gingivalis
- B. Entamoeba histolytica
- C. Lamblia
- D. Trichomonas tenax
Correct Answer: D
Rationale: The correct answer is D: Trichomonas tenax. Trichomonas tenax is a flagellated protozoan that is commonly found in the oral cavity, specifically in dental plaque. The description provided in the question matches the characteristics of Trichomonas tenax, such as unicellular structure, distinct layers in the cytoplasm, wide pseudopodia, and barely visible core. Entamoeba gingivalis (choice A) and Entamoeba histolytica (choice B) are amoebas, not flagellated protozoa, and they do not exhibit the characteristics described in the question. Lamblia (choice C) is also an incorrect choice as it is a different type of protozoan that does not match the description provided.
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Which bacteria is known for causing tuberculosis?
- A. Mycobacterium tuberculosis
- B. Mycobacterium leprae
- C. Escherichia coli
- D. Streptococcus pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Mycobacterium tuberculosis. This bacterium is known for causing tuberculosis, as it specifically infects the lungs and can lead to serious respiratory issues. Mycobacterium leprae (Choice B) causes leprosy, not tuberculosis. Escherichia coli (Choice C) is a common bacteria found in the intestines and is not associated with tuberculosis. Streptococcus pneumoniae (Choice D) causes pneumonia, but not tuberculosis. Therefore, the correct choice is A because Mycobacterium tuberculosis is the specific bacterium responsible for causing tuberculosis.
The generic name of a drug refers to its __________ name.
- A. trade
- B. proprietary
- C. chemical
- D. nonproprietary
Correct Answer: D
Rationale: The correct answer is D: nonproprietary. The generic name of a drug is the official, nonproprietary name given to a drug by an organization such as the U.S. Food and Drug Administration (FDA). This name is not owned by any specific company and is used universally to identify the drug's active ingredient. The generic name helps to communicate the specific medication being prescribed and allows for cost-effective options for consumers.
A: Trade name refers to the brand name given to a drug by a pharmaceutical company.
B: Proprietary name is another term for the trade name, specific to the company that produces the drug.
C: Chemical name refers to the exact chemical composition of the drug, which may not be user-friendly or easily recognized by healthcare professionals or consumers.
Which of the following best describes a Gram-negative bacterium?
- A. Has a thick peptidoglycan layer
- B. Has an outer membrane with lipopolysaccharides
- C. Stains purple
- D. Has no cell wall
Correct Answer: B
Rationale: The correct answer is B because Gram-negative bacteria have an outer membrane with lipopolysaccharides, which is a key characteristic used in Gram staining. This outer membrane is responsible for the pink/red color seen when stained with Gram stain. Choice A is incorrect because Gram-negative bacteria have a thin peptidoglycan layer. Choice C is incorrect because Gram-negative bacteria stain pink, not purple. Choice D is incorrect because all bacteria have a cell wall, but Gram-negative bacteria have a different structure compared to Gram-positive bacteria.
Which bacteria is responsible for causing whooping cough?
- A. Bordetella pertussis
- B. Clostridium tetani
- C. Haemophilus influenzae
- D. Staphylococcus aureus
Correct Answer: A
Rationale: The correct answer is A: Bordetella pertussis. This bacterium causes whooping cough by attaching to the respiratory tract and releasing toxins that lead to severe coughing fits. Clostridium tetani causes tetanus, not whooping cough. Haemophilus influenzae can cause respiratory infections but not specifically whooping cough. Staphylococcus aureus is known for causing skin infections and not respiratory diseases like whooping cough. Therefore, the presence of Bordetella pertussis and its specific mechanism of causing whooping cough makes it the correct answer.
Which bacteria are known to produce an endotoxin that can cause septic shock?
- A. Salmonella enterica
- B. Escherichia coli
- C. Pseudomonas aeruginosa
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D because all three bacteria (Salmonella enterica, Escherichia coli, Pseudomonas aeruginosa) are known to produce endotoxins, specifically lipopolysaccharides in their cell walls. Endotoxins are released upon bacterial cell death and can trigger an immune response, leading to septic shock. Salmonella and E. coli are common causes of bacterial infections, while Pseudomonas is associated with nosocomial infections. Therefore, all of the above choices are correct in terms of producing endotoxins that can cause septic shock. Choices A, B, and C are incorrect individually because they do not encompass all the bacteria known to produce endotoxins that can lead to septic shock.