Biology Vocabulary Cell cycle The regular pattern of growth, DNA duplication, and cell division that occurs in eukaryotic cells Mitosis The division of the cell nucleus and its contents Cytokinesis The process that divides the cell cytoplasm Chromosome One long continuous thread of DNA that consist of numerous genes along with regulatory information Histones Group of proteins, that organizes chromosomes and around which DNA wraps Chromatin The loose combination of DNA and proteins Chromatid One half of duplicated chromosomes Centromere A region of the condensed chromosomes that holds sister chromosomes together (looks pinched) Telomeres Repeating nucleotides at the ends of DNA molecules that do not form genes. They help prevent the loss of genes Prophase First phase of mitosis when chromatin condenses, nuclear envelope breaks down, the nucleus disappears, and the centrosomes and centrioles migrate to opposite sides of the cell Biology Vocabulary Metaphase Second stage in mitosis, the spindle fibers attached to a protein structure on the centromere of each chromosome and aligns the chromosomes along the cell equator Anaphase Third stage in mitosis, sister chromatids separate from each other, the spindle fibers begin to shorten and pull the sister chromatids away from each other Telophase The fourth stage of mitosis, a complete set of identical chromosomes is positioned at each pole of the self, the nuclear membrane start to form, the chromosomes begin to uncoil, and the spindle fibers fall apart Growth factor A broad group of proteins that stimulate cell division Apoptosis Programmed cell death Cancer The common name for a class of diseases characterized by uncontrolled cell division Benign Having no dangerous effect on health. It can be removed. Malignant Cancerous tumor in which cells break away and spread to other parts of the body, causing harm to the organisms health Metastasize When cancer cells break away Carcinogens Substances known to produce or promote the development of cancer