front 1 Operator | back 1 In bacterial and phage DNA, a sequence of nucleotides near the start of an operon to which an active repressor can attach. The binding of the repressor prevents RNA polymerase from attaching to the promoter and transcribing the genes of the operon |
front 2 Operon | back 2 A unit of genetic function found in bacteria and phages, consisting of a promoter, and operator, and a coordinately regulated cluster of genes whose products function in a common pathway |
front 3 Repressor | back 3 A protein that inhibits gene transcription. In prokaryotes, repressors bind to the DNA in or near the promoter. In Eukaryotes, the repressors, may bind to control elements within enhancers, to activators, or to other proteins in a way that blocks activators from binding to DNA |
front 4 Regulatory Gene | back 4 A gene that codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes |
front 5 Corepressor | back 5 A small molecule that binds to a bacterial protein and changes the protein's shape, allowing it to bind to the operator and switch an operon off |
front 6 Inducer | back 6 A specific small molecule that binds to a bacterial repressor protein and changes the repressor's shape so that it cannot bind to an operator; thus switching an operon on |
front 7 cyclic AMP (cAMP) | back 7 Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells. It is also a regulator of some bacterial operons. |
front 8 Activator | back 8 A protein that binds to DNA and stimulates gene transcription. In prokaryotes, activators bind in or near the promoter. In eukaryotes, activators generally bind to control elements in enhancers |
front 9 Differential gene expression | back 9 The expression of different sets of genes by cells with the same genome |
front 10 histone acetylation | back 10 The attachment of acetyl groups to certain amino acids of histone proteins |
front 11 DNA methylation | back 11 The presence of methyl groups on the DNA bases (usually cytosine) of plants, animals, and fungi. Also refers to the process of adding methyl groups onto DNA bases. |
front 12 epigenetic inheritance | back 12 inheritance of traits transmitted by mechanisms that do no involve the nucleotide sequence |
front 13 control elements | back 13 A segment of noncoding DNA that helps regulate transcription of a gene by serving as a binding site for transcription |
front 14 enhancers | back 14 A segment of eukaryotic DNA containing multiple control elements, usually located far from the gene whose transcription it regulates |
front 15 Alternative RNA splicing | back 15 A type of eukaryotic gene regulation at the RNA-rpocessing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which an introns |
front 16 microRNAs (miRNA) | back 16 A small, single-stranded RNA molecule, generated from a double stranded RNA precursor. The miRNA associates with one or more pre tines in a complex that can degrade or prevent translation of an mRNA with a complementary sequence |
front 17 small interfering RNAs (siRNA) | back 17 One of multiple small, single-stranded RNA molecules generated by cellular machinery from a long, linear, double stranded RNA molecule. The siRNA associates with one or more proteins in a complex that can degrade or prevent translation of an mRNA with a complementary sequence |
front 18 RNA interference (RNAi) | back 18 A mechanism for silencing the expression of specific genes. In RNAi, double-stranded RNA molecules that match the sequence of a particular gene are processed into siRNAs that either block translation or trigger the degradation of the gene's messenger RNA. This happens naturally in some cells, and can be carried out in a lab |
front 19 Differentiation | back 19 The process by which a cell or group of cells becomes specialized in structure and function |
front 20 morphogenesis | back 20 The development of the form of an organism and its structures |
front 21 cytoplasmic determinant | back 21 a maternal substance, such as a protein or RNA, that when placed into an egg influences the course of early development by regulating the expression of genes that affect the developmental fate of cells |
front 22 Induction | back 22 A process in which a group of cells or tissues influences the development of another group through close-range interactions |
front 23 Determination | back 23 The progressive restriction of developmental potential in which the possible fate of each cell becomes more limited as an embryo develops. At the end of determination, a cell is committed to its fate |
front 24 Pattern Formation | back 24 The development of a multicellular organism's spatial organization, the arrangement or organs and tissues in their characteristic places in three-dimensional space |
front 25 Positional Information | back 25 Molecular cues that control pattern formation in an animal or plant embryonic structure by indicating a cell's location relative to the organism's body axes. These cues elicit a response by genes that regulate development |
front 26 Homeotic genes | back 26 Any of the master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate or groups of cells |
front 27 embryonic lethal | back 27 A mutation with a phenotype leading to death of an embryo or larvae |
front 28 Maternal effect gene | back 28 A gene that, when mutant in the mother, results in a mutant phenotype in the offspring, regardless of the offspring's genotype. Also called egg polarity genes, were first identified in Drosophilia |
front 29 bicoid | back 29 A maternal effect gene that codes for a protein responsible for specifying the anterior end in Drosophilia |
front 30 morphogen | back 30 A substance, such as Bicoid protein in Drosophilia, that provides positional information in the form of a concentration gradient along an embryonic axis |
front 31 oncogenes | back 31 A gene found in viral or cellular genomes that is involved in triggering molecular events that can lead to cancer |
front 32 proto-oncogenes | back 32 A normal cellular gene that has the potential to become an oncogene |
front 33 tumor-surpressor genes | back 33 A gene whose protein product inhibits cell division, thereby preventing the uncontrolled cell growth that contributes to cancer |
front 34 ras gene | back 34 A gene that codes for Ras, a G protein that relays a growth signal from a growth factor receptor on the plasma membrane to a cascade of protein kinases, ultimately resulting in stimulation of the cell cycle |
front 35 p53 gene | back 35 A tumor-surpressor gene that codes for a specific transcription factor that promotes the synthesis of proteins that inhibit the cell cycle |