Cultures of a bacterial species were incubated on the shelf of a refrigerator, out on a lab bench top, on the shelf of a 37°C incubator, and on the shelf of a 50°C incubator After incubation, there was no growth at 37°C and 50°C, slight growth out on the bench top, and abundant growth at refrigeration. What term could be used for this species?
Halophile
Anaerobe
Mesophile
Psychrophile
Capnophile
The Correct Answer is D
A. Halophile: Halophiles are organisms that thrive in high-salt environments. The description of temperature-based growth does not indicate a preference for saline conditions, so this term would not apply to the observed growth pattern.
B. Anaerobe: Anaerobes are organisms that grow in the absence of oxygen. The scenario focuses on temperature preferences, not oxygen requirements.
C. Mesophile: Mesophiles grow optimally at moderate temperatures, typically between 20°C and 45°C, with 37°C being ideal for many human-associated mesophilic bacteria. Because this species did not grow at 37°C or 50°C, it does not fit the definition of a mesophile.
D. Psychrophile: Psychrophiles are organisms that thrive at cold temperatures, usually with optimal growth at 0–15°C and survival at temperatures below 20°C. The abundant growth in the refrigerator and minimal growth at room temperature, with no growth at 37°C or higher, indicates that this species is adapted to cold environments, fitting a psychrophile definition.
E. Capnophile: Capnophiles require elevated levels of carbon dioxide for optimal growth. The growth pattern described is based on temperature rather than carbon dioxide levels, so this term is not applicable.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
A. Coccus: A coccus is a spherical or round-shaped bacterium. Cocci can exist singly, in pairs (diplococci), chains (streptococci), clusters (staphylococci), or other arrangements depending on their pattern of division. The shape is an important morphological characteristic used in bacterial identification and classification in clinical microbiology.
B. Bacillus: A bacillus refers to a rod-shaped bacterium. Bacilli can occur singly or in chains and may be aerobic or anaerobic. Their elongated shape distinguishes them from cocci and influences how they move, attach to surfaces, and form spores.
C. Vibrio: A vibrio is a comma-shaped or curved rod-shaped bacterium. Vibrio species, such as Vibrio cholerae, are typically associated with aquatic environments and have distinct motility patterns. Their curved morphology differentiates them from cocci and bacilli.
Correct Answer is A
Explanation
A. Positive-sense RNA: Positive-sense RNA viruses possess genomes that function directly as messenger RNA (mRNA). After entering the host cell, the viral RNA can immediately bind to host ribosomes and begin translation to produce viral proteins. No transcription step is required before protein synthesis, these viruses can rapidly initiate replication once infection occurs.
B. Negative-sense RNA: Negative-sense RNA viruses have genomes that are complementary to mRNA and therefore cannot be translated directly by host ribosomes. Before protein synthesis can occur, the virus must first use an RNA-dependent RNA polymerase to synthesize a complementary positive-sense RNA strand. Only this newly formed RNA can function as mRNA for protein production.
C. Double-stranded RNA: Double-stranded RNA viruses contain both a positive and a negative RNA strand. However, the host cell cannot directly translate the double-stranded genome. The virus must first use viral RNA polymerase enzymes to transcribe the negative strand into a positive-sense RNA that can serve as mRNA for translation.
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