An organism with a temperature growth range of 45 to 60°C would be called
an extremophile.
thermoduric.
a facultative psychrophile.
a thermophile.
a psychrophile.
The Correct Answer is D
A. an extremophile: Extremophiles are organisms that thrive in extreme environmental conditions, such as very high or very low pH, salinity, or pressure. While thermophiles can be considered a type of extremophile, the term extremophile is broader and does not specifically describe organisms adapted primarily to high temperatures.
B. thermoduric: Thermoduric organisms are those that can survive short exposures to high temperatures but do not necessarily grow optimally at those temperatures. They are often heat-resistant spores or bacteria that survive pasteurization, rather than thriving at 45–60°C.
C. a facultative psychrophile: Facultative psychrophiles are organisms capable of growing at low temperatures but can tolerate higher temperatures. Their optimal growth range is typically below 20°C, making this classification inconsistent with a 45–60°C growth range.
D. a thermophile: Thermophiles are microorganisms that grow optimally at elevated temperatures, typically between 45°C and 80°C. They possess enzymes and cellular structures adapted to resist denaturation at high temperatures, which allows them to thrive in environments such as hot springs, compost piles, or industrial processes.
E. a psychrophile: Psychrophiles are cold-loving organisms that grow optimally at temperatures below 15°C and are adapted to Arctic, Antarctic, or deep-sea habitats. A growth range of 45–60°C is far beyond their tolerance, making this classification incorrect.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
A. Pilus: During bacterial conjugation, a specialized structure called a sex pilus (or conjugation pilus) forms a direct connection between two bacterial cells. The donor cell transfers a copy of plasmid DNA or other genetic material through this pilus to the recipient cell, allowing for horizontal gene transfer and the spread of traits such as antibiotic resistance.
B. Capsule: The bacterial capsule is a polysaccharide layer that surrounds the cell wall and provides protection against phagocytosis and desiccation. It does not play a role in the transfer of DNA between bacterial cells, and therefore is not involved in conjugation.
C. Flagellum: The flagellum is a whip-like appendage that enables bacterial motility. While important for movement and chemotaxis, it is not used for DNA transfer during conjugation. DNA exchange occurs specifically through the pilus, not through flagella.
Correct Answer is A
Explanation
A. Exotoxin: Exotoxins are proteins secreted by bacteria that can cause damage to the host by interfering with cellular processes. In tetanus, Clostridium tetani produces tetanospasmin, an exotoxin that affects the nervous system by blocking inhibitory neurotransmitters, leading to muscle rigidity and spasms. Exotoxins are highly potent and often responsible for the major clinical symptoms of bacterial infections.
B. Endotoxin: Endotoxins are lipopolysaccharide components of the outer membrane of Gram-negative bacteria. They are released mainly when bacteria die and the cell wall breaks down. Endotoxins can trigger fever, inflammation, and septic shock but are not protein toxins and do not cause the neuromuscular effects seen in tetanus.
C. Capsule: A bacterial capsule is a polysaccharide layer surrounding the cell wall that helps bacteria evade phagocytosis and immune defenses. While it contributes to bacterial virulence, it is not a toxin and does not directly cause the neurological symptoms characteristic of tetanus infection.
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