ATI RN
microbiology chapter 11 test bank Questions
Question 1 of 5
During examination of a 3-month old infant a pediatrician revealed that the baby's oral mucosa and tongue were covered with a thick white deposit. In the material taken from the affected site a bacteriologist revealed the presence of yeast fungi giving the reasons for suspecting a fungal infection which occurs most often in children of this age, namely:
Correct Answer: A
Rationale: The correct answer is A: Candidiasis. In infants, a thick white deposit on the oral mucosa and tongue is indicative of oral thrush, which is caused by the yeast fungus Candida. Infants are particularly susceptible to Candidiasis due to their developing immune systems and use of antibiotics. Favus (
B) is a chronic fungal infection of the scalp caused by Trichophyton schoenleinii, typically not seen in infants. Epidermophytosis (
C) refers to superficial fungal infections of the skin caused by dermatophytes, not commonly found in the oral cavity of infants. Actinomycosis (
D) is a bacterial infection caused by Actinomyces species, not a fungal infection.
Question 2 of 5
Which one of the following statements about Rickettsiae is true?
Correct Answer: D
Rationale:
Rationale:
1. Rickettsiae are obligate intracellular bacteria, hence they do not form spores, capsules, or flagella.
2. They have a slim glycocalyx layer, aiding in attachment to host cells.
3. Bipolar fimbriae are structures that help in adhesion to host cells.
Therefore, all statements (A, B, and
C) are true for Rickettsiae, making option D the correct answer. Other choices are incorrect as they do not accurately describe the characteristics of Rickettsiae.
Question 3 of 5
Axial filaments consist of
Correct Answer: A
Rationale: Axial filaments, also known as endoflagella, are composed of proteins. These proteins form a helical structure that enables certain bacteria, such as spirochetes, to move in a corkscrew-like motion. Proteins are the main structural component of axial filaments due to their flexibility and ability to generate movement.
Choice B, polyphosphates, are not typically associated with axial filaments, as they are more involved in energy storage and transfer.
Choice C, volutin granules, are storage inclusions of inorganic polyphosphate and are not part of axial filaments.
Choice D, carbohydrates, are not the primary component of axial filaments which are protein-based structures responsible for bacterial motility.
Question 4 of 5
A wound infection culture revealed Gram-positive cocci in clusters. The bacteria were catalase-positive and coagulase-positive. What is the most likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Staphylococcus aureus. This bacterium is characterized by Gram-positive cocci in clusters, catalase-positive, and coagulase-positive. Staphylococcus aureus is a common pathogen causing wound infections due to its ability to produce toxins and enzymes. Staphylococcus epidermidis (
B) is catalase-positive but coagulase-negative, making it less likely to cause infections. Streptococcus pyogenes (
C) is catalase-negative and typically causes streptococcal infections, not wound infections. Enterococcus faecalis (
D) is catalase-negative and typically associated with urinary tract infections. Thus, Staphylococcus aureus is the most likely causative agent based on the given characteristics.
Question 5 of 5
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.