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Cards In This Set
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What does the cytoskeleton of eukaryotes consist of?
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Microtubules, microfilaments, and intermediate filaments that interact with many organelles
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What are microtubules? What are some examples?
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They have multiple functionsCilia and flagella are two eukaryotic motile structures composed of microtubules
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How does Paramecium feed?
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By propelling food particles towards their oral grooves. This allows food to collect until the cell forms a food vacuole via phagocytosis
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How do Rotifers feed?
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By propelling food into their mouth structures
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What do microfilaments do?
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Cause pseudopodia of a cell to move by assembling and disassembling networks of microfilaments to create viscous and liquid regions of the cytoplasm, called plasmagel and plasmosal
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How do organelles in Paramecium move?
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Through microfilaments (this is the exception, most organelles are moved by microtubules)
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Why are we studying an exception to the rule?
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Because it is a good system for observing food vacuole movement
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What is the role of intermediate filaments?
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They have structural roles in the cell. Visible nuclei are contained by the intermediate filaments
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What is contrast?
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The difference between an object and its surrounding medium
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What are stains?
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Coloured compounds that react with particular components of cells and increase contrast
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How do stains function?
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Most stains have a preference to a particular class of macromolecules (lipid, protein, nucleic acid, or polysaccharide) and bind to these molecules with varying degrees
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What are vital and fixed stains?
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Vital stains are applied to live specimens. Fixed stains are applied to dead cells
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What are issues with vital stains?
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They eventually kill the cell and do not stain very intensely
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How can you improve contrast in a light microscope?
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By decreasing the amount of light (because otherwise the intensity of the light passing through the cell and the medium is the same)
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How does a phase contrast microscope work?
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Takes advantage of the fact that the cell and the medium each have a different refractive index - they slow the light that passes through them to different extentsHigher refractive index appear dark (the light slows and bends more) and areas of lower refractive index appear lighter
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