Protozoan motility structures include
cilia.
flagella
pseudopods.
cilia and pseudopods only.
cilia, flagella, and pseudopods.
The Correct Answer is E
A. Cilia: Cilia are short, hair-like projections that cover the surface of some protozoa. They beat in coordinated waves to facilitate locomotion and help direct food particles toward the oral groove. Ciliary movement allows protozoa such as Paramecium to navigate aquatic environments efficiently.
B. Flagella: Flagella are long, whip-like appendages that provide motility to certain protozoa, including Euglena. The undulating motion of flagella propels the organism through liquid environments, enabling it to seek nutrients and favorable conditions.
C. Pseudopods: Pseudopods are temporary cytoplasmic extensions formed by the flow of cytoplasm. Protozoa such as Amoeba use pseudopods for movement and phagocytosis, allowing them to engulf food particles and migrate toward stimuli.
D. Cilia and pseudopods only: While some protozoa possess cilia and pseudopods, this option excludes flagella, which are a common motility structure in many protozoan species. Limiting motility to only these two structures does not represent the full range observed in protozoa.
E. Cilia, flagella, and pseudopods: Protozoan motility encompasses all three structures. Different species utilize one or more of these mechanisms depending on their morphology and ecological niche. Cilia, flagella, and pseudopods collectively allow protozoa to move, capture food, and respond to environmental stimuli.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
A. All cells arise from pre-existing cells: This principle, articulated by Rudolf Virchow, emphasizes that cellular reproduction occurs through division of existing cells. The existence of a syncytium does not contradict this principle because the multinucleated structure can arise from the fusion of multiple cells or nuclear division without cytokinesis.
B. The cell is the basic unit of structure and function: Classical cell theory defines the cell as an autonomous, discrete unit of life with its own cytoplasm and nucleus. In syncytial tissues, multiple nuclei share a common cytoplasm, blurring the boundaries of individual cellular units. This challenges the notion of cells as independent structural and functional entities.
C. All organisms are composed of one or more cells: Syncytial tissues still meet this principle because they are formed by cellular components and exist within multicellular organisms. The organism-level composition remains consistent with classical cell theory.
D. Cells contain hereditary information: The presence of multiple nuclei within a shared cytoplasm does not negate that nuclei house DNA or hereditary material. Each nucleus maintains genetic information, so this principle is upheld even in syncytial structures.
Correct Answer is A
Explanation
A. Glycocalyx: The glycocalyx is a sticky, gelatinous layer found external to the cell wall in some bacteria and eukaryotic cells. It is primarily composed of polysaccharides and sometimes proteins. This structure functions in adherence to surfaces, protection against desiccation, and evasion of host immune responses, making it essential for colonization and virulence in pathogenic microbes.
B. Capsule: A capsule is a well-organized, dense form of glycocalyx that surrounds certain bacterial cells. While all capsules are glycocalyx, not all glycocalyx is a capsule; the term “capsule” specifically refers to a structured, tightly bound layer that provides enhanced protection and virulence.
C. Membrane: The membrane, including the plasma or cytoplasmic membrane, is a lipid bilayer that controls selective permeability and transport. It is not the sticky, gelatinous external layer.
D. Viroid: A viroid is an infectious, small circular RNA molecule that infects plants. It is unrelated to cellular coatings or structural layers and does not consist of polysaccharides or proteins.
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