Nokea
Fungi are free-living _________ organisms:
- A. autotrophic
- B. chemotrophic
- C. heterotrophic
- D. phototrophic
Correct Answer: C
Rationale: The correct answer is C: heterotrophic. Fungi are heterotrophic organisms that obtain nutrients by absorbing organic compounds from their environment. They do not produce their own food through photosynthesis (option A: autotrophic) or chemosynthesis (option B: chemotrophic). Fungi also do not rely on light for energy (option D: phototrophic). Therefore, the correct choice is C as it accurately describes the nutritional mode of fungi.
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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.
Mycoplasma species lack:
- A. Cell wall
- B. Plasma membrane
- C. DNA
- D. Ribosomes
Correct Answer: A
Rationale: The correct answer is A: Cell wall. Mycoplasma species lack a cell wall, making them unique among bacteria. This is because they have a flexible cell membrane that provides structural support instead of a rigid cell wall. The absence of a cell wall allows them to be pleomorphic and gives them resistance to certain antibiotics targeting cell wall synthesis. Plasma membrane (B), DNA (C), and ribosomes (D) are present in Mycoplasma species, so they are not the correct answer.
A wound culture from a patient with an infected ulcer revealed Gram-positive rods with terminal spores. What is the most likely causative agent?
- A. Clostridium perfringens
- B. Bacillus anthracis
- C. Clostridium tetani
- D. Bacillus cereus
Correct Answer: A
Rationale: Step-by-step rationale:
1. Gram-positive rods with terminal spores suggest Clostridium genus.
2. Terminal spores are characteristic of Clostridium perfringens.
3. C. perfringens is known to cause wound infections.
4. Therefore, the most likely causative agent is Clostridium perfringens.
Summary:
A: Clostridium perfringens is correct due to its characteristic features and association with wound infections.
B: Bacillus anthracis does not typically form terminal spores.
C: Clostridium tetani causes tetanus, not wound infections.
D: Bacillus cereus does not produce terminal spores like Clostridium perfringens.
The cleaning of glassware and tableware in restaurants falls into the category of
- A. degermation.
- B. sterilization.
- C. disinfection.
- D. sanitization.
Correct Answer: D
Rationale: The correct answer is D: sanitization. Sanitization is the process of reducing the number of microorganisms on surfaces to a safe level. In restaurants, cleaning glassware and tableware aims to eliminate harmful bacteria to prevent foodborne illnesses. Degermation (A) focuses on removing germs from a specific area, sterilization (B) eliminates all microorganisms, and disinfection (C) reduces the number of pathogens but may not completely eliminate them, making them less effective choices for this context.
Malaria is caused by a:
- A. virus
- B. bacterium
- C. helminth
- D. protozoan
Correct Answer: D
Rationale: The correct answer is D: protozoan. Malaria is caused by Plasmodium parasites transmitted through the bite of infected female Anopheles mosquitoes. These parasites belong to the protozoa kingdom, not viruses (choice A), bacteria (choice B), or helminths (choice C). Protozoa have complex life cycles involving both mosquito and human hosts, leading to the development of malaria in humans. Other choices are incorrect as they do not align with the known etiology and characteristics of malaria.