Nokea
Which of the following bacteria is responsible for causing peptic ulcers?
- A. Escherichia coli
- B. Helicobacter pylori
- C. Streptococcus pyogenes
- D. Mycobacterium tuberculosis
Correct Answer: B
Rationale: The correct answer is B: Helicobacter pylori. This bacterium is known to be the primary cause of peptic ulcers by colonizing the stomach lining and causing inflammation. It produces urease enzyme to neutralize stomach acid and has a flagellum for mobility. Escherichia coli (A) is mainly associated with foodborne illnesses. Streptococcus pyogenes (C) causes strep throat and skin infections. Mycobacterium tuberculosis (D) causes tuberculosis, a respiratory infection. Therefore, Helicobacter pylori is the correct choice for peptic ulcers based on its unique characteristics and pathogenicity.
You may also like to solve these questions
Family Retroviriade:
- A. Their capsid consists of two copies of ssRNA(-)
- B. Are with complex type of symmetry
- C. Are helical, enveloped viruses
- D. Are helical, non-enveloped viruses
Correct Answer: A
Rationale: Step-by-step rationale:
1. Family Retroviridae is known for having a single-stranded RNA genome.
2. The (-) sign indicates that the RNA strand is negative-sense.
3. Therefore, the correct answer A, "Their capsid consists of two copies of ssRNA(-)," is accurate.
Summary:
- Choice B is incorrect because Retroviridae have simple type of symmetry.
- Choice C is incorrect as Retroviridae are not enveloped viruses.
- Choice D is incorrect because Retroviridae are enveloped viruses.
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.
An enzyme process of producing two identical copies of DNA from one original DNA molecule is called:
- A. Translation
- B. Transcription
- C. Replication
- D. Cell division
Correct Answer: C
Rationale: The correct answer is C: Replication. In DNA replication, the original DNA molecule is unwound and each strand serves as a template to synthesize a new complementary strand. This results in two identical copies of the original DNA molecule. Translation (A) is the process of synthesizing proteins from mRNA. Transcription (B) is the process of synthesizing mRNA from DNA. Cell division (D) is the process of a cell dividing into two daughter cells, not specifically producing identical DNA copies. Therefore, replication is the correct answer as it specifically refers to the process of copying DNA to produce two identical copies.
A 43-year-old cattle farm worker is brought to the surgeon with fever, malaise, and inflamed lesions on his hands and arms. He reports that about 2 weeks before his presentation at the hospital he noticed small, painless, pruritic papules that quickly enlarged and developed a central vesicle. The vesicles developed into erosion and left painless necrotic ulcers with black, depressed eschar. Gram's staining of the ulcer reveals gram-positive spore-forming bacilli. Which of the following diseases is the most likely cause of these findings?
- A. Anthrax
- B. Chickenpox
- C. Syphilis
- D. Tularemia
Correct Answer: A
Rationale: The correct answer is A: Anthrax. The clinical presentation of painless necrotic ulcers with black eschar, along with the gram-positive spore-forming bacilli seen on Gram's staining, is classic for cutaneous anthrax. Anthrax is caused by Bacillus anthracis, which produces spores and can lead to skin lesions in individuals working with animals or animal products. Choice B, Chickenpox, typically presents with vesicular rash all over the body. Choice C, Syphilis, is caused by Treponema pallidum and does not present with the characteristic eschar seen in the patient. Choice D, Tularemia, caused by Francisella tularensis, presents with ulceroglandular lesions but lacks the black eschar characteristic of anthrax.
The most common causative agents of bacterial meningitis are:
- A. Neisseria meningitidis
- B. Streptococcus pneumonia, Neisseria Meningitidis, hemophilus influenz
- C. Rubella virus
- D. Herpangina
Correct Answer: B
Rationale: The correct answer is B because Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae are the most common causative agents of bacterial meningitis. Streptococcus pneumoniae is a leading cause in adults, Neisseria meningitidis is common in adolescents and young adults, and Haemophilus influenzae is more frequent in children. The other choices, Rubella virus (C) and Herpangina (D), are not bacterial agents known to cause meningitis.