 | Term | Definition |
| |
Cell |
A membrane-bound structure that is the basic unit of life |
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Cell membrane |
The lipid bilayer that forms the outer boundary of a cell |
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Cell theory |
The theory that all living things are made up of cells, that cells are the basic units of organisms, and that cells come only from existing cells |
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Eukaryote |
A cell that contains a nucleus and membrane-bound organelles |
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Nucleus |
in a eukaryotic cell, the organelle that contains most of the DNA and directs most of the cell’s activities |
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Organelle |
One of several formed bodies with a specialized function that is suspended in the cytoplasm and found in eukaryotic cells |
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Prokaryote |
A unicellular organism that lacks a nucleus and membrane-bound organelles |
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Actin |
One of two protein filaments in a muscle cell that function in contraction |
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Cell wall |
A rigid structure that surrounds the cells of plants, fungi, many protests, and most bacteria |
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Chloroplast |
A plastid containing chlorophyll; the site of photosynthesis |
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Chromatin |
The DNA and proteins in the nucleus of a nondividing cell |
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Chromosome |
DNA and protein in a coiled, rod-shaped form that occurs during cell division |
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Cilium |
A short, hairlike organelle that extends from a cell and functions in locomotion or in the movement of substances across the cell surface |
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Crista |
A fold of the inner membrane of mitochondria |
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Cytoplasm |
The region of a cell between the cell membrane and the nucleus |
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Cytoskeleton |
A network of long protein strands in the Cytosol that helps maintain the shape and size of a eukaryotic cell |
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Cytosol |
The gelatin-like aqueous fluid that bathes the organelles on the inside of the cell membrane |
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Endoplasmic reticulum |
A system of membranous tubules and sacs in eukaryotic cells that functions as a path along which molecules move from one part of the cell to another |
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Flagellum |
A hair-like structure made up of microtubules that function in locomotion |
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Fluid mosaic model |
A model of cell membrane structure representing the dynamic nature of membrane lipids and proteins |
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Golgi apparatus |
A system of membranes in eukaryotic cells that modifies proteins for export by the cell |
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Integral protein |
A protein imbedded in the bilayer of the cell membrane |
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Lysosome |
An organelle containing digestive enzymes, existing primarily in animal cells |
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Microfilament |
A polymer chain of the protein actin; the smallest strand in the cytoskeleton |
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Microtubule |
A hollow tube of protein that constitutes the largest strand in the cytoskeleton |
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Mitochondrion |
The organelle that is the site of aerobic respiration in eukaryotic cells |
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Nuclear envelope |
A double membrane that surrounds the nucleus of a eukaryotic cell |
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Nuclear matrix |
The nuclear skeleton, a shape-maintaining protein |
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Nuclear pore |
A small hole in the nuclear envelope through which substances pass between the nucleus and the cytoplasm |
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Nucleolus |
In a eukaryotic cell, the organelle that contains most of the DNA and directs most of the cell’s activities |
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Peripheral protein |
A protein attached to the interior or external surface of the cell membrane |
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Plastid |
An organelle of plant cells that contains starch, fats, or pigments |
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Ribosome |
An organelle that functions in the synthesis of proteins |
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Rough endoplasmic reticulum |
The portion of the endoplasmic reticulum that contains attached ribosomes |
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Selectively permeable membrane |
A membrane that keeps out some molecules but allows others to pass through |
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Smooth endoplasmic reticulum |
The portion of the endoplasmic reticulum that lacks attached ribosomes |
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Spindle fiber |
One of the microtubules that extend across a dividing eukaryotic cell; assists in the movement of chromosomes |
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Thylakoid |
A flattened, membranous sac inside a chloroplast; contains most of the components involved in the light reactions of photosynthesis |
| |
Vacuole |
A fluid-filled organelle that stores enzymes or metabolic wastes in a plant cell |
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