If bacteria living in salty seawater were displaced to a freshwater environment, the cell structure that would prevent the cells from rupturing is the
slime layer.
endospore.
cell wall.
capsule.
cell membrane.
The Correct Answer is C
A. slime layer: The slime layer is an extracellular, loosely attached structure that helps bacteria adhere to surfaces and evade host defenses. It provides no significant protection against osmotic pressure changes, so it would not prevent the cell from bursting in a hypotonic freshwater environment.
B. endospore: Endospores are dormant, highly resistant structures formed by certain bacteria to survive extreme environmental stress, such as heat, desiccation, or chemicals. While they provide long-term survival, they do not actively prevent osmotic lysis in vegetative cells exposed to hypotonic conditions.
C. cell wall: The bacterial cell wall, composed of peptidoglycan in most bacteria, provides rigidity and structural support. It counteracts the osmotic pressure that builds when water moves into the cell in a hypotonic environment, preventing the cytoplasm from swelling and lysing. This is the primary structure that maintains bacterial integrity under osmotic stress.
D. capsule: The capsule is a gelatinous layer that surrounds some bacteria and provides protection from phagocytosis and desiccation. It does not contribute significantly to withstanding osmotic pressure differences and would not prevent cell rupture in hypotonic conditions.
E. cell membrane: The cell membrane is selectively permeable and controls the movement of substances in and out of the cell. While it is essential for cellular function, it alone cannot withstand the osmotic pressure caused by a sudden influx of water; the rigid cell wall is required to prevent lysis.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Transcription is the process by which a segment of DNA is copied into RNA by RNA polymerase. In eukaryotic cells, transcription occurs within the nucleus, where DNA is housed, allowing for the synthesis of messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA) before RNA is processed and exported to the cytoplasm for translation. In prokaryotic cells, which lack a membrane-bound nucleus, transcription occurs in the nucleoid region, where the circular DNA resides. Therefore, transcription takes place in the nucleus of eukaryotes or at the nucleoid in prokaryotes.
Correct Answer is D
Explanation
A. Genitourinary system: The genitourinary system, including the kidneys, bladder, and reproductive organs, is not primarily affected by Creutzfeldt-Jakob disease (CJD). This disease does not target urinary function or reproductive structures.
B. Digestive system: The digestive system, which includes organs such as the stomach, intestines, liver, and pancreas, is not the main site of pathology in CJD. Gastrointestinal symptoms are generally absent or secondary to systemic decline.
C. Circulatory system: The heart, blood vessels, and blood components are not directly impacted by CJD. Circulatory dysfunction is not a hallmark of the disease, though secondary effects like immobility could influence cardiovascular health.
D. Nervous system: Creutzfeldt-Jakob disease primarily affects the central nervous system. It is caused by prions, misfolded proteins that induce neurodegeneration, leading to rapidly progressive dementia, motor dysfunction, and neurological decline. The brain tissue shows spongiform changes, making the nervous system the main system affected.
E. Respiratory system: The respiratory system is not the primary target of CJD. While respiratory complications may arise late in the disease due to immobility or aspiration, they are secondary consequences rather than a direct effect of the disease process.
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