Summary Chapter 17 Definitions Cell Cycle cycle of creating new cells complete cycle takes 18 24 hrs Interphase long growth period between cell division G1 Gap 1 Primary growth phase very active growth S Synthesis Synthesis of DNA for next cell division G2 gap 2 final growth phase before cell division Mitotic Phase cell division phase takes less than 1 hour Mitosis Nuclear divison duplicated DNA is distributed between two daughter nucli nucleus divides Cytokinesis Cytoplasm divides two new daughter cells are formed Chromosomes Rod like structures of tightly coiled chromatin Visible in the nucleus during cell division human DNA has 46 chromosomes Replication the process of copying DNA prior to cell division involves making exact copies of all 46 chromosomes Gene Short segment of DNA that contains the code or recipe for a protein smallest function of DNA Messenger RNA mesenger ribonucleic acid Transcription The process of copying DNA of a gene into mRNA occurs within the cell nucleus Translation process of converting mRNA template into one or more Mutations Alterations or mistakes in the DNA code occurs frequently during DNA replication some mutations are repaired by proteins enzymes causes chemical and physical forces Effects of mutations 1Silent mutations have no effect 2Many mutations are harmful may result in cell death or cancer 3some mutations are beneficial Introns a noncoding nucleotide sequence of DNA Codon sequence of 3 mRNA bases codes for amino acids Start AUG methionine begins all genes Stop UAA UAG UGA one ends each gene Transfer RNA Short chain RNA molecule that transfers amino acids to the ribosome Ribosome made of ribosomal RNA and proteins contains sites for mRNA and incoming amino acid tRNA and contains the enzymes factors that catalyze the peptide bond formation Ribosomal RNA the RNA component of a ribosome assists in Mitosis Process of nuclear division daughter cells are identical to protein synthesis the parent cell 1Prophase mitotic spindle forms centrioles migrate to cell poles chromatin condenses into visible chromosomes nuclear membrane dissolves metabolic activity decreases 2Metaphase duplicate chromosomes from single line at the equator between centriole poles 3Ananphase duplicate chromosomes separate daughter chromosomes are pulls toward poles by microtubles 4Telophase reverse of prophase mitotic spindle disintegrates nuclear membrane reforms chromosomes uncoil and revert to chromatin Cytokinesis the division of cytoplasm that occurs after a cell nucleus has divided Diploid the number of chromosomes in a body cell Homologous Chromosomes chromosomes that look identical under the microscope Haploid half of the diploid number the number of chromosomes in a gamete function Meiosis Nuclear division process that reduces the chromosomal number by half Preparing for sexual reproduction Differentiation the process in which a cell changes in form or Clone production of identical copies of a gene cell or organism Reproductive Cloning producing a copy of an entire organism Therapeutic Cloning cloning specifically for treating patients