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30 Cards in this Set
- Front
- Back
archaea
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one of the two divisions of procaryotes, often found in hostile environments such as hot springs or concentrated brine
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bacteria
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commonly used name for any procaryotic organism, but more precisely refers to one of the three major domains of life; most are single-celled organisms; some species cause disease
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cell
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the basic unit from which living organisms are made, consisting of an aqueous solution of organic molecules enclosed by a membrane; all arise from pre-existing ones, usually by a process of division
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chloroplast
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specialized organelle in algae and plants that contains chlorophyll and in which photosynthesis takes place
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chromosome
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long threadlike structure composed of DNA and associated proteins that carries the genetic information of an organism; especially visible when plant and animal cells undergo mitosis or meiosis
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cytoplasm
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contents of a cell that are contained within its plasma membrane but, in the case of eucaryotic cells, outside the nucleus
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cytoskeleton
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system of protein filaments in the cytoplasm of a eucaryotic cell that gives the cell shape and the capacity for directed movement; its most abundant components are actin filaments, microtubules, and intermediate filaments
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cytosol
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contents of the main compartment of the cytoplasm, excluding membrane-enclosed organelles such as endoplasmic reticulum and mitochondria; the cell fraction remaining after membranes, cytoskeletal components, and other organelles have been removed
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DNA
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double-stranded polynucleotide formed from two separate chains of covalently linked deoxyribonucleotide units; it serves as the cell's store of genetic information that is transmitted from generation to generation
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endoplasmic reticulum
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labyrinthine, membrane-enclosed compartment in the cytoplasm of eucaryotic cells, where lipids and secreted and membrane-bound proteins are made
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eucaryote
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living organism composed of one or more cells with a distinct nucleus and cytoplasm; includes all forms of life except archaea and bacteria (the procaryotes) and viruses
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evolution
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the gradual change in living organisms taking place over generations that results in new species being formed
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genome
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the total genetic information carried by a cell or an organism (or the DNA molecules that carry this information)
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Golgi apparatus
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membrane-enclosed organelle in eucaryotic cells where the proteins and lipids made in the endoplasmic reticulum are modified and sorted for transport to other sites
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homologous
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describes organs or molecules that are similar because of their common evolutionary origin; specifically it describes similarities between protein sequences or nucleic acid sequences
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lysosome
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intracellular membrane-enclosed organelle containing digestive enzymes, typically those most active at the acid pH found in these organelles
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micrometer
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unit of measurement often applied to cells and organelles; equal to 10^-6 meter or 10^-4 centimeter
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microscope
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instrument for viewing extremely small objects; light utilizes a focused beam of visible light and is used to examine cells and organelles; electron utilizes a beam of electrons and can be used to examine objects as small as individual molecules
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mitochondrion
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membrane-enclosed organelle about the size of a bacterium, that carries out oxidative phosphorylation and produces most of the ATP in eucaryotic cells
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model organism
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selected for intensive study as a representative of a large group of species; examples are the mouse (representing mammals), the yeast Saccharomyces cerevisiae (representing a unicellular eucaryote), and Escherichia coli (representing bacteria)
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nanometer
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unit of length commonly used to measure molecules and cell organelles; equal to 10^-3 micrometer or 10^-9 m
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nucleus
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the major organelle of a eucaryotic cell, which contains DNA organized into chromosomes; also, when referring to an atom, the central mass built from neutrons and protons
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organelle
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a discrete structure or subcompartment of a eucaryotic cell (especially one that is visible in the light microscope) that is specialized to carry out a particular function; examples include mitochondria and the Golgi apparatus
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peroxisome
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small membrane-enclosed organelle that uses molecular oxygen to oxidize organic molecules; contains some enzymes that produce hydrogen peroxide and others that degrade it
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plasma membrane
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surrounds a living cell
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procaryote
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major category of living cells distinguished by the absence of a nucleus; comprise the archaea and the eubacteria (commonly called bacteria), two of the three domains of life
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protein
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the major macromolecular constituent of cells; each is composed of one or more linear chains of amino acids linked together by peptide bonds in a specific sequence; the amino acid chain is folded into a three-dimensional shape that is unique to each one and determines its function
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protozoan
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a member of the free-living, nonphotosynthetic, single-celled, motile eucaryotic organisms; many such as Paramecium or Amoeba live by feeding on other organisms
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ribosome
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associates with messenger RNA and catalyzes the synthesis of protein
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RNA
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a (usually) single-stranded polynucleotide in the form of a chain of covalently linked ribonucleotide subunits; serves a variety of functions in cells
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