Nokea
Which bacteria are capable of surviving in anoxic (oxygen-free) conditions?
- A. Obligate anaerobes
- B. Facultative anaerobes
- C. Obligate aerobes
- D. Microaerophiles
Correct Answer: A
Rationale: The correct answer is A: Obligate anaerobes. These bacteria can only survive in the absence of oxygen as they lack the enzymes needed for aerobic respiration. They typically use fermentation or anaerobic respiration for energy production.
Incorrect choices:
B: Facultative anaerobes can switch between aerobic and anaerobic metabolism based on oxygen availability.
C: Obligate aerobes require oxygen for survival and cannot survive in anoxic conditions.
D: Microaerophiles require low levels of oxygen for growth and are not capable of surviving in completely anoxic conditions.
You may also like to solve these questions
The sample used to proving epidemic meningitis is:
- A. CSF transported at 37°C (CSF sample, blood, nasopharyngeal secretion)
- B. Feces
- C. CSF transported at +4°C
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A because CSF (Cerebrospinal fluid) is the sample used for proving epidemic meningitis. It should be transported at 37°C to maintain its integrity. Blood and nasopharyngeal secretions are not typically used for diagnosing meningitis. Choice B, feces, is unrelated to the diagnosis of meningitis. Choice C, CSF transported at +4°C, is incorrect as it should be transported at 37°C to prevent degradation of the sample. Therefore, A is the correct choice for proving epidemic meningitis due to the specificity of the sample and the proper transport conditions.
Bacteria are studied by:
- A. Taxonomy
- B. Classification
- C. Identification
- D. Nomenclature
Correct Answer: C
Rationale: The correct answer is C: Identification. Bacteria are studied by identification to determine their specific characteristics and differentiate between different species. Taxonomy (A) is the science of classification, not specific to bacteria. Classification (B) is the process of grouping organisms based on shared characteristics, not specific to bacteria. Nomenclature (D) is the naming system for organisms, not the primary method for studying bacteria. Therefore, identification (C) is the correct choice for studying bacteria.
For which family the following morphological features are typical: filamentous spiral nucleocapsid, linear unsegmented single strand (-) RNA and lipid bilayer membrane of cellular origin:
- A. Picornaviridae
- B. Filoviridae
- C. Orthomyxoviridae
- D. Togaviridae
Correct Answer: B
Rationale: Step-by-step rationale:
1. Filamentous spiral nucleocapsid is characteristic of Filoviridae, such as Ebola virus.
2. Linear unsegmented single strand (-) RNA is a key feature of Filoviridae genomes.
3. The lipid bilayer membrane of cellular origin is found in Filoviridae viruses.
4. Therefore, the correct answer is B (Filoviridae) due to the alignment of all three morphological features.
Summary:
- A (Picornaviridae): Has an icosahedral capsid, not filamentous spiral.
- C (Orthomyxoviridae): Has a segmented genome, not linear unsegmented.
- D (Togaviridae): Has a spherical capsid, not filamentous spiral.
A child presented with foul-smelling diarrhea. Stool microscopy revealed trophozoites with two nuclei and flagella. What is the causative agent?
- A. Giardia lamblia
- B. Entamoeba histolytica
- C. Trichomonas vaginalis
- D. Balantidium coli
Correct Answer: A
Rationale: The correct answer is A: Giardia lamblia. Giardia lamblia is a protozoan parasite that causes foul-smelling diarrhea. The trophozoites of Giardia lamblia have two nuclei and flagella, which are characteristic features seen on stool microscopy. The presence of these specific features helps differentiate Giardia lamblia from the other options. Entamoeba histolytica (B) typically presents with one nucleus and lacks flagella. Trichomonas vaginalis (C) is a sexually transmitted parasite with a different morphology. Balantidium coli (D) is a ciliated parasite, not flagellated like Giardia lamblia.
A 37-year-old male was admitted to a hospital complaining of abdominal pain, difficulty in swallowing and breathing, constipation, and nausea. He developed respiratory failure and required endotracheal intubation and ventilation. Two days before, the patient consumed dried salted fish bought from an artisanal producer. Laboratory investigation for infectious pathogen was performed using Kitt-Tarozzi's method. Observation under a bright field microscopy revealed the presence of typical microorganisms with tennis racket appearance. Which of the following is the most likely diagnosis?
- A. Botulism
- B. Cholera
- C. Nontyphoidal Salmonella infection
- D. Typhoid fever
Correct Answer: A
Rationale: The correct answer is A: Botulism. Botulism is caused by the toxin produced by Clostridium botulinum bacteria found in improperly preserved or canned foods. The symptoms described align with botulism, such as difficulty swallowing and breathing due to muscle paralysis. The tennis racket appearance seen under microscopy corresponds to the characteristic appearance of Clostridium botulinum spores. The other choices can be ruled out based on the clinical presentation and microscopy findings. Cholera typically presents with severe watery diarrhea, Nontyphoidal Salmonella infection with fever and gastrointestinal symptoms, and Typhoid fever with high fever and abdominal pain. Therefore, the most likely diagnosis in this case is botulism.