Ch. 18 Key Concepts: - Bacteria often respond to environmental change by regulating transcription. - Eukaryotic gene expression can be regulated at any stage. - Noncoding RNAs play multiple roles in controlling gene expression. - A program of differential gene expression leads to the different cell types in a multicellular organism. - Cancer results from genetic changes that affect cell cycle control.
Terms : Hide Images
| 2778270825 | Feedback Inhibition | A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway. | 0 | |
| 2778270826 | Operator | In bacterial 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 | 1 | |
| 2843571251 | Operon | A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes with related functions. | 2 | |
| 2843571874 | Repressor | A protein that inhibits gene transcription; in prokaryotes, repressors bind to the DNA in or near the promoter; in eukaryotes, repressors may bind to control elements within enhancers, to activators, or to other proteins in a way that blocks activators from binding to DNA | 3 | |
| 2843571875 | Regulatory Gene | A gene that codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes. | 4 | |
| 2843572819 | Corepressor | a small molecule that binds to a bacterial repressor protein and changes its shape, allowing it to switch an operon off. | 5 | |
| 2843572820 | Inducer | 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. | 6 | |
| 2843573529 | Cyclic AMP | Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells (for example, in vertebrate endocrine cells). It is also a regulator of some bacterial operons. | 7 | |
| 2843573530 | Activator | 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 | 8 | |
| 2843574398 | Differential Gene Expression | The expression of different sets of genes by cells with the same genome. | 9 | |
| 2843575267 | Histone Acetylation | The attachment of acetyl groups to certain amino acids of histone proteins. | 10 | |
| 2843575268 | Genomic Imprinting | A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent. | 11 | |
| 2843576802 | Epigenetic Inheritance | Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence. | 12 | |
| 2843576803 | Control Elements | A segment of noncoding DNA that helps regulate transcription of a gene by binding a transcription factor. Multiple control elements are present in a eukaryotic gene's enhancer. | 13 | |
| 2843577637 | Enhancers | A segment of eukaryotic DNA containing multiple control elements, usually located far from the gene whose transcription it regulates | 14 | |
| 2843577638 | Alternative RNA Splicing | A type of eukaryotic gene regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns. | 15 | |
| 2843579094 | Proteasomes | A giant protein complex that recognizes and destroys proteins tagged for elimination by the small protein ubiquitin. | 16 | |
| 2843579095 | microRNAs | A small, single-stranded RNA molecule that associates with one or more proteins in a complex that can degrade or prevent translation of an mRNA with a complementary sequence. | 17 | |
| 2843580042 | RNA Interference | A technique used to silence the expression of selected genes. RNAi uses synthetic double-stranded RNA molecules that match the sequence of a particular gene to trigger the breakdown of the gene's messenger RNA. | 18 | |
| 2843581923 | Small Interfering RNAs | affects gene expression; used by scientists to knock out a gene being studied | 19 | |
| 2843581924 | Cell Differentiation | The structural and functional divergence of cells as they become specialized during a multicellular organism's development. Cell differentiation depends on the control of gene expression. | 20 | |
| 2843582775 | Morphogenesis | The development of body shape and organization. | 21 | |
| 2843583583 | Cytoplasmic Determinants | The maternal substances in the egg that influences the course of early development by regulating the expression of genes that affect the developmental fate of cells. | 22 | |
| 2843583584 | Induction | The process in which one group of embryonic cells influences the development of another, usually by causing changes in gene expression. | 23 | |
| 2843583585 | Determination | The progressive restriction of developmental potential in which the possible fate on each cell becomes more limited as an embryo developes. At the end of determination, a cell is committed to its fate. | 24 | |
| 2843584762 | Tissue-Specific Proteins | Proteins are found only in a specific cell type and give the cell its characteristic structure and function; first evidence of differentiation is the appearance of mRNAs for these proteins. | 25 | |
| 2843584763 | Pattern Formation | The development of a multicellular organism's spatial organization, the arrangement of organs and tissues in their characteristic places in three-dimensional space. | 26 | |
| 2843585856 | Positional Information | 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. | 27 | |
| 2843585857 | Homeotic Genes | A master control gene that determines the identity of a body structure of a developing organism, presumably by controlling the developmental fate of groups of cells. | 28 | |
| 2843586784 | Embryonic Lethals | Mutations with phenotypes leading to death at the embryo or larval stage. | 29 | |
| 2843587645 | Maternal Effect Gene | A gene that, when mutant in the mother, results in a mutant phenotype in the offspring, regardless of the offspring's genotype; maternal effect genes, also called egg-polarity genes, were first identified in Drosophila melanogaster | 30 | |
| 2843589107 | Egg-Polarity Genes | A gene that helps control the orientation (polarity) of the egg. (Also known as the maternal affect gene). | 31 | |
| 2843589108 | Bicoid | A maternal effect gene that codes for a protein responsible for specifying the anterior end in Drosophila melanogaster | 32 | |
| 2843589109 | Morphogens | A substance that provides positional information in the form of a concentration gradient along an embryonic axis. | 33 | |
| 2843590206 | Oncogenes | A gene found in viral or cellualar genomes that is involved in triggering molecular events that can lead to cancer | 34 | |
| 2843590207 | Proto-Oncogenes | A normal gene which, when altered by mutation, becomes an oncogene that can contribute to cancer. | 35 | |
| 2843590945 | Tumor-Suppressor Genes | A gene whose protein product inhibits cell division, thereby preventing the uncontrolled cell growth that contributes to cancer | 36 | |
| 2843590946 | Ras Gene | 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 | 37 | |
| 2843592790 | P53 Gene | A tumor-suppressor gene that codes for a specific transcription factor that promotes the synthesis of proteins that inhibit the cell cycle | 38 |
