Nokea
Which bacteria are known for their ability to survive in extreme heat?
- A. Psychrophiles
- B. Mesophiles
- C. Thermophiles
- D. Halophiles
Correct Answer: C
Rationale: The correct answer is C: Thermophiles. Thermophiles are bacteria that thrive in high temperatures typically above 45°C. They have specialized enzymes and cellular structures that allow them to survive and even thrive in extreme heat. Psychrophiles (A) are adapted to cold temperatures, mesophiles (B) thrive at moderate temperatures, and halophiles (D) prefer high salt concentrations, making them unsuitable for extreme heat survival. Therefore, Thermophiles are the only bacteria among the choices that are known for their ability to survive in extreme heat.
You may also like to solve these questions
Which is NOT a property of interferon?
- A. Released from infected cells
- B. Acts extracellularly to inactivate virus
- C. Coded for by cellular DNA
- D. Not virus-specific but is cell-specific
Correct Answer: D
Rationale: Interferon is a cell-specific protein that is produced and released from infected cells in response to viral infections. It acts extracellularly to interfere with viral replication, not to inactivate the virus itself. Interferon is not coded for by cellular DNA, but by viral RNA during infection. Therefore, the correct answer, D, is that interferon is not virus-specific but is cell-specific. This is because interferon can be produced by various cell types in response to different types of viral infections, making it a broad-spectrum antiviral defense mechanism.
Which one is FALSE:
- A. Tissue samples and aspirations are better specimens than the swabs for diagnosis of skin and soft tissue infections
- B. To prove anaerobic agents. The specimen should be collected from the surface of the wound.
- C. The skin rash in some infections is due to the excessive production
- D. Healthy skin is an impenetrable barrier for the microorganisms
Correct Answer: B
Rationale: The correct answer is B because collecting specimens from the surface of a wound does not provide adequate samples for anaerobic agent detection. Anaerobic agents thrive in deep tissue environments with low oxygen levels, making surface specimens unreliable. Tissue samples and aspirations (choice A) are superior for diagnosing skin infections. Excessive production of toxins, not skin rash (choice C), causes symptoms in some infections. While healthy skin provides some protection, it is not completely impenetrable to microorganisms (choice D).
A patient diagnosed with botulism has been prescribed antibotulinic serum for treatment. What immunity will be formed in the given patient?
- A. Antitoxic passive immunity
- B. Infection immunity
- C. Antitoxic active immunity
- D. Antimicrobic active immunity
Correct Answer: A
Rationale: The correct answer is A: Antitoxic passive immunity. Antibotulinic serum contains pre-formed antibodies against the botulinum toxin, providing immediate protection to the patient. This is passive immunity as the patient does not produce their antibodies but receives them externally. Choice B is incorrect as botulism is not an infection, so the patient does not develop infection immunity. Choice C is incorrect because active immunity involves the body producing its antibodies after exposure to an antigen, which is not the case here. Choice D is incorrect as antimicrobic immunity relates to protection against microbes, not toxins like in botulism.
What is the main component of bacterial cell walls?
- A. Lipopolysaccharides
- B. Cellulose
- C. Peptidoglycan
- D. Chitin
Correct Answer: C
Rationale: The correct answer is C: Peptidoglycan. Bacterial cell walls are primarily composed of peptidoglycan, a unique molecule consisting of alternating sugar chains connected by peptide cross-links. This structure provides rigidity and shape to the cell wall, protecting the bacterial cell from osmotic pressure. Lipopolysaccharides (A) are found in the outer membrane of Gram-negative bacteria. Cellulose (B) is a component of plant cell walls, not bacterial cell walls. Chitin (D) is a polysaccharide found in the exoskeletons of arthropods and fungi, not in bacterial cell walls.
Which of the following is an active transport mechanism?
- A. pinocytosis
- B. facilitated diffusion
- C. filtration
- D. pinocytosis
Correct Answer: D
Rationale: The correct answer is D: pinocytosis. This is an active transport mechanism where cells engulf fluids or solutes through vesicles. Energy is required to transport substances against a concentration gradient. A is incorrect as pinocytosis is an active process, not passive like pinocytosis. B is incorrect as facilitated diffusion is a passive process that uses carrier proteins to move substances down a concentration gradient. C is incorrect as filtration is a passive process that relies on pressure gradients to move substances across a barrier. Therefore, D is the correct choice as it involves the active transport of substances into the cell.