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4.1 and 4.2 Bio
Term | Definition |
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cell | in biology, the smallest unit that can perform all life processes; cells are covered by a membrane and contain DNA and cytoplasm |
cell theory | the theory that states that all living things are made up of cells, that cells are the basic units of organisms, that each cell in a multicellular organism has a specific job, and that cells come only from existing cells |
plasma membrane | a phospholipid layer that covers the cells surface and acts ass a barrier between the inside of the cell and its wall |
cytoplasm | the region of the cell within the membrane that includes the fluid, the cytoskeleton, and all of the organelles except the nucleus |
cytosol | the soluble portion of the cytoplasm, which includes molecules and small particles, such as ribosomes, but not the organelles covered with membranes |
nucleus | in a eukaryotic cell, a membrane-bound organelle that contains he cell's DNA and that has a role in processes such as growth, metabolism, and reproduction |
organelle | 1 of the small bodies that are found in e cytoplasm of a cell and that are specialized to perform a specific function |
prokaryote | a single-celled organism that does not have a nucleus or membrane-bound organelles; examples are archaea and bacteria |
eukaryote | an organism made up of cells that have a nucleus enclosed by a membrane, multiple chromosomes, and a mitotic cycle; eukaryotes include protists, animals, plants, and fungi but not archaea or bacteria |
tissue | a group of similar cells that perform a common function |
organ | a collection of tissues that carry out a specialized function of the body |
organ system | a group of organs that work together to perform body functions |