ATI RN
microbiology an introduction 12th edition test bank Questions
Question 1 of 9
Trichinosis is an infection caused by ingestion of a:
Correct Answer: A
Rationale: The correct answer is A: nematode. Trichinosis is caused by the roundworm Trichinella spiralis, a type of nematode. Nematodes are multicellular parasites commonly found in raw or undercooked meat. Viruses, bacteria, and fungi do not cause trichinosis. Viruses are not parasitic worms, bacteria are single-celled organisms, and fungi are eukaryotic organisms distinct from nematodes. Therefore, the ingestion of nematodes, not viruses, bacteria, or fungi, leads to trichinosis.
Question 2 of 9
Which one is true about sexually transmitted infections?
Correct Answer: A
Rationale: The correct answer is A because a soft chancre is a type of sexually transmitted infection caused by the bacterium Haemophilus ducreyi. It presents as a painless ulcer on the genitals. The other choices are incorrect. B is incorrect because STIs can enter the body through various routes, not only the urogenital tract mucosa. C is incorrect because immunity to syphilis is not lifelong; reinfection is possible. D is incorrect because STIs can occur in any country regardless of social status or hygiene levels.
Question 3 of 9
Enzymes that remove functional groups from a substrate without adding water, or that add functional groups to a double bond, are called
Correct Answer: D
Rationale: The correct answer is D: lyases. Lyases are enzymes that catalyze the breaking of chemical bonds without the addition of water. They can remove functional groups from substrates or add functional groups to double bonds without the use of water. A: Oxidoreductases involve the transfer of electrons. B: Transferases transfer functional groups from one molecule to another. C: Hydrolases catalyze the breaking of bonds by adding water.
Question 4 of 9
Gram-negative rods producing red colonies on Endo agar were isolated from a fecal sample. The bacteria were lactose-fermenting. What microorganism is likely responsible?
Correct Answer: A
Rationale: The correct answer is A: Escherichia coli. E. coli is a Gram-negative rod that ferments lactose, leading to red colonies on Endo agar. This bacterium is commonly found in the human gut and is known for its ability to ferment lactose. Salmonella and Shigella are also Gram-negative rods but do not ferment lactose, so they would not produce red colonies on Endo agar. Proteus is a Gram-negative rod that is not known for its lactose-fermenting ability and would not produce red colonies on Endo agar. Therefore, based on the characteristics provided, E. coli is the most likely microorganism responsible for the red colonies on Endo agar.
Question 5 of 9
A 32-year-old patient undergoing dental examination was found to have some rash-like lesions resembling secondary syphilis in the oral cavity. The patient was referred for the serological study with the purpose of diagnosis confirmation. In order to detect antibodies in the serum, living Treponema were used as diagnosticum. What serological test was performed?
Correct Answer: B
Rationale: The correct answer is B: Passive hemagglutination. In this test, red blood cells coated with Treponema antigens agglutinate in the presence of patient's serum antibodies. This indicates the presence of antibodies against Treponema, confirming the diagnosis. A: Immobilization test uses live Treponema to detect specific antibodies, but it is not commonly used for syphilis diagnosis. C: Precipitation test is not commonly used for syphilis diagnosis. D: Complement binding test is not specific for syphilis and is used more for autoimmune diseases. Therefore, passive hemagglutination is the most appropriate serological test in this case due to its specificity and relevance to the presentation of the patient.
Question 6 of 9
A patient with a productive cough and fever had a Gram-positive cocci isolated from a sputum sample. The bacteria were catalase-positive and coagulase-negative. What is the likely microorganism?
Correct Answer: A
Rationale: The correct answer is A: Staphylococcus epidermidis. 1. Gram-positive cocci suggest a staphylococcal species. 2. Catalase-positive indicates it belongs to the Staphylococcus genus. 3. Coagulase-negative rules out Staphylococcus aureus. 4. Staphylococcus epidermidis is a common cause of infections in immunocompromised patients. Summary: - B: Staphylococcus aureus is coagulase-positive. - C: Streptococcus pneumoniae is a Gram-positive diplococci. - D: Neisseria meningitidis is a Gram-negative diplococci.
Question 7 of 9
For the structure of rubella virus is true that
Correct Answer: A
Rationale: The correct answer is A. Rubella virus has icosahedral type of symmetry due to its spherical shape with 20 faces. This symmetry allows for efficient packaging of genetic material and structural stability. Choice B is incorrect as rubella virus is an ssRNA virus, not ssDNA. Choice C is incorrect as rubella virus does have an envelope derived from the host cell membrane. Choice D is incorrect as rubella virus does have glycoprotein spikes on its surface that aid in host cell recognition and entry.
Question 8 of 9
A patient with diarrhea had stool microscopy revealing large, oval protozoa with a single nucleus and four flagella. What is the most likely causative agent?
Correct Answer: A
Rationale: Step 1: Large, oval protozoa with a single nucleus and four flagella indicate Giardia lamblia. Step 2: Giardia lamblia is a flagellated protozoan causing diarrhea. Step 3: It has a distinct appearance under microscopy. Step 4: Entamoeba histolytica causes dysentery with no flagella. Step 5: Balantidium coli is a ciliated protozoan with a larger size. Step 6: Trichomonas vaginalis lacks a cyst stage and causes genitourinary infections.
Question 9 of 9
What structure allows bacteria to exchange genetic material?
Correct Answer: A
Rationale: The correct answer is A: Pili. Pili are hair-like appendages on the surface of bacteria that facilitate the exchange of genetic material through a process called conjugation. During conjugation, bacteria can transfer plasmids and other genetic material to neighboring bacteria through pili. This allows for the exchange of beneficial traits like antibiotic resistance. Choice B, Flagella, are involved in bacterial movement and not in genetic material exchange. Choice C, Endospores, are protective structures formed by bacteria in response to harsh conditions, but they are not involved in genetic material exchange. Choice D, Capsules, are protective layers around bacteria that help in adherence to surfaces and evasion of the immune system, but they do not play a role in genetic material exchange.