ATI RN
microbiology chapter 11 test bank Questions
Question 1 of 9
Binary fission is a form of reproduction used by
Correct Answer: B
Rationale: Binary fission is a form of asexual reproduction where a single organism divides into two equal parts. Bacteria reproduce through binary fission, splitting into two identical daughter cells. Viruses are not considered living organisms and reproduce by infecting host cells. Fungi reproduce through spores or sexual reproduction. Helminths are parasitic worms that reproduce sexually. Therefore, the correct answer is B, bacteria, as they specifically utilize binary fission for reproduction.
Question 2 of 9
A patient with a sore throat and fever had a throat culture revealing Gram-positive cocci in chains. The bacteria were catalase-negative. What is the most likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pyogenes. This bacterium fits the description of Gram-positive cocci in chains and is catalase-negative. S. pyogenes commonly causes sore throat (pharyngitis) and fever, making it the most likely causative agent in this scenario. Staphylococcus aureus (B) is catalase-positive and is not typically associated with pharyngitis. Enterococcus faecalis (C) is not typically found in chains and is rarely a cause of acute pharyngitis. Micrococcus luteus (D) is not typically associated with pharyngitis and is catalase-positive.
Question 3 of 9
During bacteriological examination of sputum of a child with choking cough and fever there were revealed glossy smooth colonies growing on casein-charcoal agar and reminding of mercury drops. Microscopic examination revealed short Gram-negative bacteria. What microorganism was secured from the sputum?
Correct Answer: A
Rationale: The correct answer is A: Bordetella pertussis. Glossy smooth colonies growing on casein-charcoal agar resembling mercury drops indicate Bordetella pertussis, the causative agent of whooping cough. The presence of short Gram-negative bacteria further supports this identification. Option B, Haemophilus influenzae, typically grows as small, round, translucent colonies on chocolate agar. Option C, Corynebacterium diphtheriae, forms gray colonies on tellurite agar. Option D, Klebsiella pneumoniae, appears as mucoid colonies on MacConkey agar.
Question 4 of 9
The establishment and further spreading of an infectious disease within a new population is a process called:
Correct Answer: A
Rationale: The correct answer is A: emergence. The term emergence refers to the process of a new infectious disease appearing and spreading within a population. It signifies the initial introduction and establishment of the disease in the new population. Explanation for other choices: B: Adoption does not accurately describe the process of a disease spreading within a new population. C: Inclusion is not a term commonly used to describe the spread of infectious diseases. D: Appearance is too vague and does not capture the complexity of the process of establishment and spreading of an infectious disease.
Question 5 of 9
Which of the following sites of the human body does not have a normal flora?
Correct Answer: D
Rationale: The correct answer is D: Blood. Normal flora refers to the microorganisms that naturally inhabit specific areas of the body. Blood is considered a sterile environment in healthy individuals, meaning it does not harbor any microorganisms under normal circumstances. In contrast, the intestine, skin, and vagina all have normal flora as they provide suitable environments for various microbial species to thrive. The presence of normal flora in these sites helps maintain a balance and protect against pathogenic invaders. Blood, being a vital and sterile fluid, is not meant to have any resident microbial populations.
Question 6 of 9
A patient with a severe sore throat had a throat smear revealing Gram-positive cocci in pairs with a capsule. What is the most likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. The presence of Gram-positive cocci in pairs with a capsule is characteristic of Streptococcus pneumoniae. This bacterium is a common cause of bacterial pharyngitis, leading to a severe sore throat. Staphylococcus aureus (B) does not typically present in pairs or have a capsule. Neisseria meningitidis (C) is a Gram-negative diplococcus, not a Gram-positive cocci. Klebsiella pneumoniae (D) is a Gram-negative bacillus, not a cocci. Thus, based on the characteristics described in the question, Streptococcus pneumoniae is the most likely causative agent.
Question 7 of 9
Choose which one fo the following microorganisms is an example of obligate parasitism
Correct Answer: A
Rationale: The correct answer is A: HIV. HIV is an example of obligate parasitism because it requires a host cell to replicate and survive. It cannot live independently outside of a host organism. In contrast, choices B, C, and D are not obligate parasites. E. Coli and S. Epidermidis are examples of commensal bacteria that can live in the host without causing harm. Pseudomonas aeruginosa can be both an opportunistic pathogen and a free-living organism, not strictly dependent on a host for survival.
Question 8 of 9
The number of new cases of a disease over a certain period of time compared with the general healthy population is referred to as:
Correct Answer: A
Rationale: The correct answer is A: incidence. Incidence refers to the number of new cases of a disease occurring within a specific time period in relation to the healthy population. It helps in understanding the risk of developing the disease. Prevalence (B) is the total number of existing cases at a given point in time. Virulence (C) is the severity of the disease once contracted. Mortality (D) refers to the number of deaths due to the disease, not the new cases. Therefore, the correct term for new cases is incidence.
Question 9 of 9
Transduction is:
Correct Answer: B
Rationale: Transduction is the transfer of genetic material between bacterial cells with the help of a phage (virus). This process involves a phage infecting a bacterial cell, replicating inside it, and then transferring bacterial DNA along with phage DNA to another bacterial cell. This is different from transformation (choice A) which involves the uptake of naked DNA by a bacterial cell and plasmid transfer (choice C) which involves the transfer of small, circular DNA molecules. Therefore, the correct answer is B because it specifically describes the process of transduction in bacteria, while choices A and C describe different mechanisms of genetic transfer.