Cell Division and Genetics: Key Terms and Definitions, Quizzes of Biology

Download Cell Division and Genetics: Key Terms and Definitions and more Quizzes Biology in PDF only on Docsity! TERM 1 Binary Fission DEFINITION 1 Asexual reproduction by division of one cell or body into equal or nearly equal parts TERM 2 Septum DEFINITION 2 A wall between two cavities. TERM 3 Septation DEFINITION 3 In prokaryotic cell division, the formation of a septum where new cell membrane and cell wall is formed to separate the two daughter cells. TERM 4 Mitosis DEFINITION 4 Somatic cell division; nuclear division in which the duplicated chromosomes separate to form two genetically identical daughter nuclei. TERM 5 Chromatin DEFINITION 5 The complex of DNA and proteins of which eukaryotic chromosomes are composed; chromatin is highly uncoiled and diffuse in interphase nuclei, condensing to form the visible chromosomes in prophase. TERM 6 Heterochromatin DEFINITION 6 The portion of a eukaryotic chromosome that is not transcribed into RNA; remains condensed in interphase and stains intensely in histological preparations. TERM 7 Euchromatin DEFINITION 7 The portion of eukaryotic chromosome that is transcribed into mRNA; contains active genes that are not tightly condensed during interphase. TERM 8 Histone Protein DEFINITION 8 Any of eight proteins with an overall positive charge that associate in a complex. The DNA duplex coils around a core of eight histone proteins, held by its negatively charged phosphate groups, forming a nucleosomes. TERM 9 Nucleosome DEFINITION 9 A complex consisting of a DNA duplex would around a core of eight histone proteins. TERM 10 Condensin DEFINITION 10 A protein complex involved in condensation of chromosomes during mitosis and meiosis. TERM 21 Centromere DEFINITION 21 A visible point of constriction on a chromosome that contains repeated DNA sequences that bind specific proteins. These proteins make up the kinetochore to which mircotubules attach during cell division. TERM 22 Kinetochore DEFINITION 22 Disc- shaped protein structure within the centromere to which the spindle fibers attach during mitosis or meiosis. TERM 23 Condensation DEFINITION 23 The process during the G2 phase of mitosis during which chromosomes become tightly coiled and visible. TERM 24 Centriole DEFINITION 24 A cytoplasmic organelle located outside the nuclear membrane, identical in structure to a basal body; found in animal cells and in the flagellated cells of other groups; divides and organizes spindle fibers during mitosis and meiosis. TERM 25 Tubulin DEFINITION 25 Globular protein subunit forming the hollow cylinder of mircotubules. TERM 26 Prophase DEFINITION 26 The phase of cell division that begins when the condensed chromosomes become visible and ends when the nuclear envelope breaks down. The assembly of the spindle takes place during prophase. TERM 27 Spindle DEFINITION 27 The structure composed of microtubules radiating from the poles of the dividing cell that will ultimately guide the sister chromatids to the two poles. TERM 28 Prometaphase DEFINITION 28 The transitional phase between prophase and metaphase during which the spindle attaches to the kinetochores of sister chromatids. TERM 29 Metaphase DEFINITION 29 The stage of mitosis or meiosis during which microtubules become organized into a spindle and the chromosomes come to lie in the spindle's equatorial plane. TERM 30 Anaphase DEFINITION 30 In mitosis and meiosis II, the stage initiated by the separation of sister chromatids, during which the daughter chromosomes move to opposite poles of the cell; in meiosis I, marked by separation of replicated homologous. TERM 31 Telophase DEFINITION 31 Telophase, "stage") is the final stage in both meiosis and mitosis in a eukaryotic cell. TERM 32 Cytokinesis DEFINITION 32 Division of the cytoplasm of a cell after nuclear division TERM 33 Cleavage Furrow DEFINITION 33 The constriction that forms during cytokinesis in animal cells that is responsible for dividing the cell into two daughter cells. TERM 34 Cell Plate DEFINITION 34 The structure that forms at the equator of the spindle during telophase in the dividing cells of plants and a few green algae. TERM 35 Middle Lamella DEFINITION 35 The layer of intercellular material, rich in pectic compounds, that cements together the primary walls of adjacent plant cells.