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Basic Unit of Life



domain encompassing unicellular organisms that lack nuclei or membrane-bound organelles that do not contain peptidoglycan in their cell walls


domain encompassing unicellular organisms that lack nuclei or membrane-bound organelles that contain peptidoglycan in their cell walls

cell wall

rigid carbohydrate structure that provides overall support and protection for the cell


membrane-bound organelle found in plants and some other organisms that captures energy from light and converts it into chemical energy


structure that contains DNA, the genetic material that is passed from one generation to the next


group of phototrophic bacteria that are bluish-green in color and produce oxygen as a product of photosynthesis


combination of cytosol—a jellylike fluid primarily made up of water and dissolved substances that fills the spaces around the internal cell structures—and organelles (excluding the nucleus)

deoxyribonucleic acid (DNA)

organic molecule containing coded instructions for the life processes of an organism; consists of nucleotides bonded together in the form of a double helix


largest taxonomic grouping

endoplasmic reticulum (ER)

network of membranes that helps process molecules in a cell and transports cell materials; may be rough (ribosomes attached) or smooth (without ribosomes attached)


symbiotic relationship in which one organism lives inside another


organism characterized by membrane-bound organelles, such as the nucleus


when defined narrowly, a change in gene frequencies within a population from one generation to the next

fungus (plural, fungi)

eukaryotic organism that may be unicellular or multicellular and that produces spores and contains chitin (a polysaccharide used for structure) in its cell walls


unit of heritable material that codes for a particular trait

Golgi apparatus

organelle that attaches chemical markers to molecules produced in the endoplasmic reticulum in order to transport the molecules to their places inside or outside a cell


organelle that digests bacteria that enter a cell, eliminates toxins, and recycles worn cell materials

mitochondrion (plural, mitochondria)

organelle that changes energy from food into energy a cell can use


membrane-bound organelle that contains most of the genetic material (DNA); this structure directs a cell's growth, division, and death


membrane-bound structure in a cell that has a specific task, such as a mitochondrion or Golgi apparatus


structure in eukaryotes that transforms fatty acids into sugars and aids chloroplasts in oxidizing plant sugars

plasma membrane

membrane that encloses a cell and is made of layers of lipids, organic molecules made of carbon and hydrogen


unicellular organism with no nucleus


structure composed of RNA and protein that constructs proteins based on the instructions provided by DNA. It may be free-floating in cytoplasm or attached to form rough endoplasmic reticulum.