Nokea
F pili:
- A. Are made up of nucleotides
- B. Are transferred to the recipient cell
- C. Are proteins on the F+ donor that are attached to specific receptors of the recipient's cell wall
- D. Are part of the recipient cell for attachment to the donor cell
Correct Answer: C
Rationale: The correct answer is C because F pili are proteins on the F+ donor cell that are attached to specific receptors on the recipient cell's cell wall. This is essential for the transfer of genetic material during conjugation. Choice A is incorrect because F pili are not made up of nucleotides, but rather proteins. Choice B is incorrect because F pili are not transferred to the recipient cell itself, but they facilitate the transfer of genetic material. Choice D is incorrect because F pili are not part of the recipient cell, but rather part of the donor cell for attachment to the recipient cell.
You may also like to solve these questions
How many types of herpes simplex virus are there?
- A. 1
- B. 2
- C. 3
- D. 4
Correct Answer: B
Rationale: The correct answer is B because there are two types of herpes simplex virus: HSV-1 and HSV-2. HSV-1 typically causes oral herpes, while HSV-2 usually causes genital herpes. Choice A is incorrect because there is more than one type. Choices C and D are also incorrect as there are only two types of herpes simplex virus known to infect humans.
Many diseases of medicinal plants are caused by bacteria of the Pseudomonas genus. Select the bacteria relating to this genus:
- A. Blue pus bacillus
- B. Colon bacillus
- C. Proteus
- D. Mycoplasma
Correct Answer: A
Rationale: The correct answer is A: Blue pus bacillus. Pseudomonas genus includes bacteria that commonly cause diseases in plants. Blue pus bacillus is a common name for Pseudomonas aeruginosa, a well-known bacterium that causes diseases in medicinal plants.
Explanation:
1. Blue pus bacillus (Pseudomonas aeruginosa) is a member of the Pseudomonas genus known for causing diseases in plants.
2. Colon bacillus (Escherichia coli) belongs to the Enterobacteriaceae family, not the Pseudomonas genus.
3. Proteus is a genus of the Enterobacteriaceae family, not Pseudomonas.
4. Mycoplasma is a genus of bacteria that lack a cell wall and are not related to the Pseudomonas genus.
In summary, the correct answer is A because it is a member of the Pseudomonas genus known for causing diseases in medicinal plants, while
Which of the following organisms is a common cause of peptic ulcers?
- A. Treponema pallidum
- B. Vibrio cholerae
- C. Helicobacter pylori
- D. Escherichia coli
Correct Answer: C
Rationale: The correct answer is C: Helicobacter pylori. This bacterium is a well-known cause of peptic ulcers due to its ability to survive in the acidic environment of the stomach and produce enzymes that weaken the protective mucous layer of the stomach lining. Treponema pallidum (choice A) causes syphilis, Vibrio cholerae (choice B) causes cholera, and Escherichia coli (choice D) can cause various infections but is not a common cause of peptic ulcers. Therefore, Helicobacter pylori is the correct answer as it is specifically associated with peptic ulcer formation.
A patient with pneumonia had sputum cultured, revealing Gram-negative rods. The bacteria were lactose fermenters and produced green colonies on MacConkey agar. What is the most likely causative agent?
- A. Escherichia coli
- B. Klebsiella pneumoniae
- C. Pseudomonas aeruginosa
- D. Proteus mirabilis
Correct Answer: A
Rationale: Rationale:
1. Gram-negative rods suggest Enterobacteriaceae family.
2. Lactose fermenters narrow down to E. coli.
3. Green colonies on MacConkey agar indicate acid production.
4. E. coli is a common cause of pneumonia.
Therefore, the most likely causative agent is Escherichia coli. Other choices are incorrect as Klebsiella is non-lactose fermenter, Pseudomonas is oxidase-positive, and Proteus is non-lactose fermenter.
A 35-year-old patient with a severe respiratory infection had sputum that showed Gram-negative, comma-shaped bacteria. What is the likely causative agent?
- A. Vibrio cholerae
- B. Shigella dysenteriae
- C. Campylobacter jejuni
- D. Helicobacter pylori
Correct Answer: C
Rationale: The correct answer is C: Campylobacter jejuni. This bacterium is Gram-negative and comma-shaped, commonly causing respiratory infections. Vibrio cholerae (A) causes cholera, not respiratory infections. Shigella dysenteriae (B) causes dysentery, not respiratory infections. Helicobacter pylori (D) is associated with gastric ulcers, not respiratory infections. Therefore, Campylobacter jejuni is the most likely causative agent based on the given information.