Nokea
The structure used for bacterial motility is:
- A. Fimbriae
- B. Capsule
- C. Flagella
- D. Pili
Correct Answer: C
Rationale: The correct answer is C: Flagella. Flagella are the structures used for bacterial motility, allowing bacteria to move towards or away from stimuli. They are long, whip-like appendages that rotate to propel the bacteria. Fimbriae (A) are short, hair-like structures used for attachment, not movement. Capsules (B) are protective layers surrounding bacteria. Pili (D) are used for adherence and conjugation, not motility. In summary, flagella are specifically designed for bacterial movement, making them the correct choice.
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The so-called “red tide†is generally caused by which of the following organisms?
- A. Lichens
- B. Bacteria
- C. Pfiesteria
- D. Dinoflagellates
Correct Answer: D
Rationale: The correct answer is D: Dinoflagellates. Red tides are caused by the rapid growth of certain species of dinoflagellates, which are single-celled algae. These algae produce toxins that can harm marine life and humans. Lichens (A) are not associated with red tides. While some bacteria (B) can contribute to harmful algal blooms, they are not the primary cause of red tides. Pfiesteria (C) is a type of harmful algal species, but it is not the main organism responsible for red tides. Therefore, the correct answer is dinoflagellates (D) due to their ability to cause red tides through toxin production.
The term “zone of inhibition†is used in which of the following procedures?
- A. Use-dilution test
- B. Growth inhibition test
- C. Disk-diffusion test
- D. Multiple inhibition test
Correct Answer: C
Rationale: The correct answer is C: Disk-diffusion test. In the disk-diffusion test, the zone of inhibition refers to the area around an antimicrobial disk where bacterial growth is inhibited. This test is used to determine the susceptibility of bacteria to specific antibiotics. The other choices, such as A: Use-dilution test, B: Growth inhibition test, and D: Multiple inhibition test, do not specifically involve measuring the zone of inhibition and are not commonly used methods for testing antibiotic susceptibility.
A man died from an acute disease characterized by fever, jaundice, hemorrhagic rash, and acute renal insufficiency. Histological examination revealed spiral bacteria shaped like 'C' and 'S' letters. Identify the pathogen.
- A. Leptospira
- B. Treponema
- C. Borrelia
- D. Spirochaeta
Correct Answer: A
Rationale: The correct answer is A: Leptospira. Leptospira is a spiral-shaped bacterium that causes a disease known as leptospirosis, characterized by fever, jajsondice, hemorrhagic rash, and renal insufficiency. The characteristic spiral shape of the bacteria, resembling 'C' and 'S' letters, is a key identifying feature. Leptospira is commonly associated with contaminated water sources and can be transmitted to humans through contact with infected animals or water.
Summary of other choices:
B: Treponema - Treponema pallidum is the causative agent of syphilis, which does not typically present with the combination of symptoms described in the question.
C: Borrelia - Borrelia species are associated with Lyme disease and relapsing fever, but do not match the specific symptoms and histological appearance described in the question.
D: Spirochaeta - Spirochaeta is a genus of bacteria, but specific species within
A lot of pyoinflammatory processes in oral cavity are caused by anaerobes. What nutrient medium can be used for control of wound textile contamination by anaerobes?
- A. Kitt-Tarozzi
- B. Endo
- C. Roux
- D. Sabouraud's
Correct Answer: A
Rationale: The correct answer is A: Kitt-Tarozzi. This medium contains blood and hemin, which are essential nutrients for the growth of anaerobes. Blood provides a source of iron, while hemin stimulates the growth of anaerobes. This combination creates an environment conducive for the isolation and identification of anaerobic organisms.
B: Endo and C: Roux are selective media primarily used for the isolation of gram-negative bacteria and not specifically designed for anaerobes.
D: Sabouraud's is a medium used for the cultivation of fungi, not anaerobes.
In summary, Kitt-Tarozzi is the correct choice due to its specific nutrient composition that supports the growth of anaerobes, unlike the other options which are not suitable for this purpose.
Which type of RNA carries the genetic code for protein synthesis?
- A. mRNA
- B. tRNA
- C. rRNA
- D. snRNA
Correct Answer: A
Rationale: The correct answer is A: mRNA. mRNA carries the genetic code from the DNA in the cell nucleus to the ribosomes in the cytoplasm, where protein synthesis occurs. It serves as a template for protein synthesis by specifying the order of amino acids. tRNA (choice B) brings amino acids to the ribosome during protein synthesis. rRNA (choice C) is a structural component of ribosomes. snRNA (choice D) is involved in RNA processing and splicing, not protein synthesis. Therefore, choice A is correct as it directly carries the genetic code for protein synthesis.