ATI RN
foundations in microbiology test bank Questions
Question 1 of 9
The enzyme used by bacteria to break down hydrogen peroxide is:
Correct Answer: B
Rationale: The correct answer is B: Catalase. Catalase is the enzyme responsible for breaking down hydrogen peroxide into water and oxygen. This process helps protect the bacteria from oxidative damage caused by hydrogen peroxide. Amylase (A), Lipase (C), and Protease (D) are enzymes that are not involved in breaking down hydrogen peroxide. Amylase is involved in breaking down starch, Lipase breaks down lipids, and Protease breaks down proteins. Therefore, they are not the correct enzymes for the given question.
Question 2 of 9
Which strain E. coli can cause bloody diarrhea in children similar to shigellosis
Correct Answer: B
Rationale: The correct answer is B: EIEC. This strain of E. coli can cause bloody diarrhea in children similar to shigellosis due to its ability to invade and replicate within the intestinal epithelial cells, leading to inflammation and bloody stools. ETEC (A) causes watery diarrhea due to enterotoxins. EAEC (C) causes persistent diarrhea. EPEC (D) causes attaching and effacing lesions on the intestinal mucosa without invasion.
Question 3 of 9
Which of the following microorganisms can cause skin infections?
Correct Answer: B
Rationale: The correct answer is B: All are correct. Candida albicans can cause skin infections such as candidiasis. Staphylococcus aureus and Streptococcus pyogenes are common bacteria that can also cause skin infections. Therefore, choice B is correct as all three microorganisms listed can cause skin infections. Choices A, C, and D are incorrect because individually, each of the microorganisms listed can cause skin infections.
Question 4 of 9
An 18-year-old patient has developed candidiasis after the case of pneumonia treated with β-lactam antibiotic. What antimycotic agent should be prescribed?
Correct Answer: A
Rationale: The correct answer is A: Fluconazole. 1. Fluconazole is an antifungal agent effective against Candida species commonly causing candidiasis. 2. Streptomycin (B) is an antibiotic used for bacterial infections, not fungal. 3. Phthalylsulfathiazole (C) is an antibacterial agent, not antifungal. 4. Ampicillin (D) is a β-lactam antibiotic, which can actually contribute to fungal infections like candidiasis.
Question 5 of 9
In which of the following GIT infections, the bacteria adhere to the intestine wall and produce toxins
Correct Answer: C
Rationale: The correct answer is C: enterotoxigenic E. Coli (ETEC). ETEC adheres to the intestine wall and produces toxins, leading to symptoms like diarrhea. Shigella spp. invade intestinal cells, Salmonella spp. cause inflammation, and Helicobacter pylori infects the stomach lining. This makes them incorrect choices for bacteria adhering to the intestine wall and producing toxins.
Question 6 of 9
Disinfection with chemicals acting on cell surface:
Correct Answer: B
Rationale: The correct answer is B: Phenols. Phenols act on the cell surface by disrupting cell membranes and denaturing proteins, leading to cell death. Soaps (A) work by lifting dirt and microbes off surfaces, not directly acting on cell surfaces. Amines (C) are typically used as disinfectants targeting specific enzymes in microbes, not cell surfaces. Polymyxin (D) is an antibiotic that works by disrupting cell membranes internally, not on the cell surface.
Question 7 of 9
Patients with similar complaints applied to the doctor: weakness, pain in the intestines, disorder of GIT. Examination of the feces revealed that one patient with four nucleus cysts should be hospitalized immediately. For what protozoa are such cysts typical?
Correct Answer: B
Rationale: The correct answer is B: Dysenteric amoeba. 1. Dysenteric amoeba causes amoebiasis, which presents with symptoms like weakness, intestinal pain, and gastrointestinal disorders. 2. The presence of four-nucleus cysts in the feces indicates an infection with Entamoeba histolytica, the causative agent of amoebiasis. 3. Multiple-nucleus cysts are characteristic of Entamoeba histolytica, distinguishing it from other protozoa. 4. Lamblia (choice A), Balantidium (choice C), and Trichomonas (choice D) are not associated with four-nucleus cysts or the mentioned symptoms, making them incorrect choices.
Question 8 of 9
Which bacteria are responsible for causing the disease tuberculosis?
Correct Answer: C
Rationale: The correct answer is C: Mycobacterium tuberculosis. This bacterium is responsible for causing tuberculosis as it specifically infects the lungs and can spread to other parts of the body. Mycobacterium leprae (A) causes leprosy, Streptococcus pneumoniae (B) causes pneumonia, and Clostridium botulinum (D) causes botulism, making them incorrect choices for tuberculosis. Mycobacterium tuberculosis has unique characteristics and mechanisms that enable it to cause tuberculosis, such as its ability to evade the immune system and form granulomas in the lungs.
Question 9 of 9
What type of bacteria is responsible for the formation of acid in the stomach?
Correct Answer: B
Rationale: The correct answer is B: Helicobacter pylori. This bacterium is responsible for stomach acid formation by producing an enzyme called urease, which converts urea into ammonia and carbon dioxide, leading to an increase in stomach pH. Staphylococcus aureus (A) does not cause stomach acid formation. Bacillus cereus (C) and Clostridium botulinum (D) are not involved in stomach acid processes.