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7Sci CH17
7th Science CH17 Basic Units of Life
Term | Definition |
---|---|
cell | basic unit of structure and function in all living things; more than 10 trillion in the human body; each has a specific job to do |
cell membrane | flexible, double-layered, outer covering of most cells; surrounds the cell’s cytoplasm |
cell wall | adaptation of plants, fungi, and bacteria, outside the cell membrane; provides support and protection for the cell |
chloroplasts | structures of the cytoplasm of green plant cells, contain chlorophyll, a green pigment that lets plant produce their own food by converting light energy into chemical energy in a sugar called glucose |
chromosomes | threadlike structures found in the nucleus of plant and animal cells, made up of protein and DNA, the molecule that control the cell’s activities, including its reproduction; can only be seen when a cell is dividing |
cytoplasm | gel-like, constantly moving material found inside the cell membrane of both plants and animals where most of the cell’s life processes take place |
mitochondria | power plants in the cell’s cytoplasm in which energy is released for organisms to do their work; food molecules are broken down here and converted into forms the cell can use |
mitosis | reproductive process of cells in which the cell nucleus divides so each new cell will have the same type and number of chromosomes as the parent cell; the original cell becomes two identical cells through this process |
nucleus | membrane-enclosed command center in the cytoplasm of plant and animal cells; has chromosomes that contain complex chemical information that directs all the cell’s activities, including its reproduction |