ATI RN
microbiology chapter 14 test bank Questions
Question 1 of 9
Production of RNA and DNA is called
Correct Answer: D
Rationale: The correct answer is D: Transcription. This is the process where the DNA sequence is copied into an RNA molecule. It is the initial step in gene expression. A: RNA splicing is the process of removing introns from pre-mRNA to create a mature mRNA molecule. B: Translation is the process of synthesizing proteins using the information from mRNA. C: Transposition is the movement of genetic elements within a genome. In summary, transcription specifically refers to the synthesis of RNA from DNA, making it the correct choice compared to the other options.
Question 2 of 9
Which of the following statements is accurate in explaining why gram-negative bacteria are generally more resistant to penicillin than gram-positive bacteria
Correct Answer: C
Rationale: The correct answer is C: gram-negative bacteria have an outer membrane that acts as an extra barrier. This outer membrane in gram-negative bacteria contains lipopolysaccharides and porins, which restrict the entry of antibiotics like penicillin. The outer membrane acts as an additional layer of protection, making it harder for penicillin to penetrate and reach its target, the peptidoglycan layer. Choices A, B, and D do not directly address the specific mechanism of resistance seen in gram-negative bacteria. Choice A focuses on transpeptidase enzyme quantity, which is not the primary reason for penicillin resistance. Choice B refers to β-lactamase enzymes in the periplasmic space, which are actually enzymes that degrade penicillin and contribute to resistance, but this is not unique to gram-negative bacteria. Choice D mentions a thicker cell wall, which is a characteristic of gram-positive bacteria, not gram-negative bacteria.
Question 3 of 9
A patient who has recently come from an endemic area presents with elevated body temperature, headache, chills, malaise, that is with the symptoms which are typical for a common cold. What laboratory tests are necessary to confirm or to refute the diagnosis of malaria?
Correct Answer: A
Rationale: The correct answer is A: Microscopy of blood smears. Malaria diagnosis is confirmed by identifying the Plasmodium parasite in a blood smear. This step is crucial as it directly visualizes the causative agent. The other choices are incorrect as they do not directly detect malaria parasites. B: Studying lymph node punctate is not specific for malaria. C: Urinalysis does not show malaria parasites. D: Studying cerebrospinal fluid is used to diagnose conditions affecting the brain and spinal cord, not malaria.
Question 4 of 9
A bacteriological laboratory tests canned meat for botulinum toxin. Extract of the tested material and ABE botulinum antitoxin serum was introduced into the test group of mice; a control group of mice received the extract without antibotulinic serum. What serological reaction was used?
Correct Answer: A
Rationale: The correct answer is A: Neutralization. In this experiment, the ABE botulinum antitoxin serum is introduced along with the extract to neutralize the botulinum toxin. This is a specific type of serological reaction where the antitoxin serum binds to and neutralizes the toxin, preventing it from causing harm. Summary: - B: Precipitation involves the formation of visible insoluble complexes, which is not the case in this experiment. - C: Complement binding involves the activation of complement proteins, which is not the main mechanism at play here. - D: Double immunodiffusion is a technique to detect the presence of specific antigens or antibodies, but it is not directly related to the neutralization of toxins as seen in this experiment.
Question 5 of 9
After continuous treatment with antibiotics a patient got symptoms of stomatitis. Examination of specimens of oral mucous membrane revealed some oval polymorphous Gram-positive microorganisms arranged in clusters. What microorganism may be the cause of such manifestations?
Correct Answer: C
Rationale: The correct answer is C: S.aureus. Stomatitis is commonly caused by S.aureus due to its ability to form clusters of oval polymorphous Gram-positive microorganisms. S.aureus is known to colonize the oral mucous membrane and can cause infections, especially after prolonged antibiotic use. Explanation for other choices: A: С.albicans - Candida albicans is a fungus commonly associated with oral thrush, not typically causing stomatitis. B: C.perfringens - Clostridium perfringens is a bacterium associated with food poisoning and gas gangrene, not commonly causing stomatitis. D: S.pyogenes - Streptococcus pyogenes is known to cause strep throat and skin infections, but not typically associated with stomatitis.
Question 6 of 9
What is a viral capsid?
Correct Answer: B
Rationale: The correct answer is B because a viral capsid is a protein coat that surrounds and protects the viral nucleic acid (DNA or RNA). It helps in the attachment of the virus to host cells and protects the genetic material during transmission. Choice A is incorrect because a viral capsid is composed of proteins, not an envelope. Choice C is incorrect because not all viruses have an outer membrane. Choice D is incorrect because a viral capsid is primarily made up of proteins, not lipids.
Question 7 of 9
What is the role of bacterial ribosomes?
Correct Answer: A
Rationale: The correct answer is A: Protein synthesis. Bacterial ribosomes are responsible for translating mRNA into proteins through a process called translation. This is a crucial step in gene expression, where amino acids are assembled into polypeptide chains. Choice B (DNA replication) is incorrect because ribosomes are not involved in DNA replication. Choice C (Flagella formation) is incorrect as ribosomes do not play a direct role in flagella formation. Choice D (Toxin production) is incorrect as ribosomes are not directly involved in producing toxins.
Question 8 of 9
Which bacteria can survive in both aerobic and anaerobic conditions?
Correct Answer: A
Rationale: The correct answer is A: Facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic conditions because they have the metabolic flexibility to switch between utilizing oxygen for respiration in aerobic conditions and using fermentation in anaerobic conditions. Obligate aerobes (B) require oxygen for survival, obligate anaerobes (C) cannot survive in the presence of oxygen, and microaerophiles (D) require low levels of oxygen to grow effectively. Therefore, the ability of facultative anaerobes to adapt to varying oxygen levels makes them the correct choice for this question.
Question 9 of 9
A patient with pulmonary tuberculosis is prescribed the most effective antituberculous antibiotic. Name this drug:
Correct Answer: D
Rationale: The correct answer is D: Rifampicin. Rifampicin is a first-line antibiotic for treating pulmonary tuberculosis due to its high efficacy against Mycobacterium tuberculosis. It works by inhibiting bacterial RNA synthesis. Furasolidone (A) is not commonly used for tuberculosis, Bactrim (B) is not a first-line drug for tuberculosis, and Streptocide (C) is not as effective as Rifampicin.