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What is a common characteristic of spore-forming bacteria?
- A. Resistance to heat and dehydration
- B. Ability to produce toxins
- C. Presence of flagella
- D. Ability to photosynthesize
Correct Answer: A
Rationale: The correct answer is A: Resistance to heat and dehydration. Spore-forming bacteria form spores as a survival mechanism in harsh conditions. These spores are highly resistant to heat and dehydration, allowing the bacteria to withstand extreme environments. This characteristic is essential for their long-term survival and ability to persist in unfavorable conditions. Choices B, C, and D are incorrect because not all spore-forming bacteria produce toxins, have flagella, or are capable of photosynthesis. These characteristics are not exclusive to spore-forming bacteria and do not define them as a group.
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The cleanup of various industrial wastes by living organisms is referred to as __________.
- A. biomining
- B. biosynthesis
- C. bioremediation
- D. bioengineering
Correct Answer: C
Rationale: The correct answer is C: bioremediation. Bioremediation is the process of using living organisms to clean up environmental pollution, including industrial wastes. This method utilizes microorganisms, plants, or fungi to break down or neutralize pollutants. Biomining (A) is the process of extracting valuable metals from ores using biological organisms. Biosynthesis (B) refers to the production of complex molecules by living organisms. Bioengineering (D) involves the application of engineering principles to biological systems, not specifically related to cleaning up industrial wastes. Therefore, the most appropriate term for the cleanup of industrial wastes by living organisms is bioremediation.
A patient with a sore throat and fever had a throat culture revealing Gram-positive cocci in pairs with a capsule. What is the most likely causative agent?
- A. Streptococcus pneumoniae
- B. Staphylococcus aureus
- C. Neisseria meningitidis
- D. Klebsiella pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is a Gram-positive cocci that often appear in pairs and can have a capsule. It is a common cause of sore throat and fever, known as streptococcal pharyngitis. Staphylococcus aureus (B) is a Gram-positive cocci but does not typically form pairs. Neisseria meningitidis (C) is a Gram-negative diplococcus and is more associated with meningitis. Klebsiella pneumoniae (D) is a Gram-negative rod and not typically associated with sore throat and fever.
The cell envelope in gram positive bacteria is:
- A. Two-layer
- B. Three-layer
- C. One-layer
- D. There is no a cell envelope in gram-positive bacteria
Correct Answer: A
Rationale: The correct answer is A: Two-layer. In gram-positive bacteria, the cell envelope consists of two layers: the thick peptidoglycan layer and the cytoplasmic membrane. The peptidoglycan layer is much thicker compared to gram-negative bacteria, providing structural support and protection. The cytoplasmic membrane is located beneath the peptidoglycan layer and serves as a barrier between the cytoplasm and the external environment. The other choices are incorrect because gram-positive bacteria do have a cell envelope, it is composed of two layers, not three layers, and it is not just a single layer. Choice D is incorrect as it states that there is no cell envelope in gram-positive bacteria, which is not true.
Which of the following is not considered to be a vehicle transmission?
- A. Airborne
- B. Insect
- C. Foodborne
- D. Bodily fluid
Correct Answer: B
Rationale: The correct answer is B: Insect. A vehicle transmission refers to the mode by which a disease spreads from one host to another. Insects can transmit diseases, making them a vehicle for transmission. Airborne, foodborne, and bodily fluid transmissions are well-known modes of disease spread, while insects are also known vectors for diseases like malaria and Zika.
A wound culture revealed Gram-positive cocci in clusters. The bacteria were catalase-positive and coagulase-negative. What is the most likely microorganism?
- A. Staphylococcus epidermidis
- B. Staphylococcus aureus
- C. Streptococcus pyogenes
- D. Enterococcus faecalis
Correct Answer: A
Rationale: The correct answer is A: Staphylococcus epidermidis. The presence of Gram-positive cocci in clusters indicates a staphylococcal species. The fact that the bacteria are catalase-positive and coagulase-negative further narrow it down to Staphylococcus epidermidis, as this species fits all the given characteristics.
- Choice B, Staphylococcus aureus, is coagulase-positive.
- Choice C, Streptococcus pyogenes, is a streptococcal species, not staphylococcal.
- Choice D, Enterococcus faecalis, is a Gram-positive cocci but is catalase-negative and not typically found in clusters.