Regulation of Gene Expression
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| 5726221788 | Operator | -off/on "switch" that controls whole cluster of functionally related genes -segment of DNA that provides coordinate control -positioned within promoter OR between promoter and enzyme coding genes -controls access of RNA polymerase to genes |  | 0 |
| 5726221789 | Operon | -operate + promoter + genes they control -entire stretch of DNA for enzyme production for tryptophan pathway -not switched off permanently b/c: 1. binding of repressors to operators is reversible 2. trp repressor is an allosteric protein w/ 2 alternative shapes: active and inactive |  | 1 |
| 5726221790 | Repressor | -protein that switches operon off -binds to operator and blocks attachment of RNA polymerase to promoter -specific for operator of particular operon |  | 2 |
| 5726221791 | Regulatory Gene (trpR) | -product of trp repressor -located some distance from operon it controls -has own promoter -expressed continuously at low rate | 3 | |
| 5726221792 | Corepressor | small molecule that cooperates w/ repressor protein to switch operon off |  | 4 |
| 5726221793 | Repressible Operon | transcription usually on but can be inhibited when specific small molecule binds allosterically to regulatory protein |  | 5 |
| 5726221794 | Inducible Operon | transcription usually off but can be stimulated when specific small molecule interacts w/ regulatory protein |  | 6 |
| 5726221795 | Inducer | specific small molecule, inactivates repressor | 7 | |
| 5726221796 | Cyclic AMP | small organic molecule which accumulates when glucose is scarce | 8 | |
| 5726221797 | Activator | protein that binds to DNA and stimulates gene transcription (ex. CAP) |  | 9 |
| 5726221798 | Differential Gene Expression | expression of different genes by cells in the same genome |  | 10 |
| 5726221799 | Histone Acetylation | -acetyl groups (-COCH3) attached to lysines in histone tails -> lysines acetylated -> positive charges neutralized -histone tails no longer bind to neighboring nucleosomes | 11 | |
| 5726221800 | Histone Code Hypothesis | specific conditions of modifications help determine chromatin configuration-influences transcription | 12 | |
| 5726221801 | Genomic Imprinting | methylation permanently regulates expression of either maternal or paternal allele of particular at start of development | 13 | |
| 5726221802 | Epigenetic Inheritance | inheritance of traits transmitted by mechanisms not directly involving nucleotide sequence | 14 | |
| 5726221803 | Control Elements | segments of noncoding DNA that help regulate transcription by binding certain proteins | 15 | |
| 5726221804 | Enhancers | -distal control elements -may be thousands of nucleotides upstream/downstream of gene or in intron | 16 | |
| 5726221806 | Alternative RNA Splicing | -different mRNA molecules produced from same primary transcript, depending on which RNA segments are treated as introns and exons -can expand repertoire of eukaryotic genome | 17 | |
| 5726221807 | Proteasome | giant protein complex recognize ubiquitin-tagged proteins and degradation 1. multiple ubiquitin molecules attached to protein by enzymes in cytosol 2. ubiquintin-tagged protein recognized by proteasome, unfolds protein and sequesters it within central cavity 3. enzymatic components by proteasome cut protein into small peptides-can be further degraded by other enzymes in cytosol |  | 18 |
| 5726221808 | microRNAs (miRNAs) | -small, single-stranded RNA molecules capable of binding to complementary sequences in mRNA molecules 1. enzyme cuts each hairpin from each primary mRNA transcript 2. dicer enzyme trims loop and single-stranded ends from hairpin-cutting arrows 3. one strand of double stranded mRNA degraded; other strand (miRNA) forms complex of 1+ proteins 4. miRNA in complex can bind to any target mRNA that contains at least 6 bases of complementary sequence 5. if miRNA and mRNA bases complementary along length, mRNA degraded; if match less complete, translation blocked |  | 19 |
| 5726221809 | RNA interference (RNAi) | injecting double-stranded RNA molecules into cell turned off expression of gene w/ same sequence as RNA | 20 | |
| 5726221810 | Small Interfering RNAs (siRNAs) | -similar in size and function to miRNAs -formed by much longer double-stranded RnA molecules -> many siRNAs | 21 | |
| 5726221811 | Cell Differentiation | process by which cells become specialized in structure and function | 22 | |
| 5726221812 | Morphogenesis | physical processes that give organism its shape | 23 | |
| 5726221813 | Cytoplasmic Determinants | maternal substances in egg that influence course of early development | 24 | |
| 5726221814 | Induction | changes in target cells caused by signals impinging on embryonic cell from others in vicinity, including contact w/ cell surface molecules on neighboring cells and binding of growth factors secreted by neighboring cells | 25 | |
| 5726221815 | Determination | -events that lead to observable differentiation of cell -once cell undergoes determination, embryonic cell irreversibly committed to final fate -marked by expression of genes for tissue specific proteins -ex. muscle cells | 26 | |
| 5726221816 | Pattern Formation | development of spatial organization where tissues and organs of organism are all in characteristic places | 27 | |
| 5726221817 | Positional Information | -molecular cues that control pattern formation -tell cell its location relative to body axes and neighboring cells and determine how cell and its progeny will respond to future signals | 28 | |
| 5726221818 | Homoeotic Genes | control pattern formation in late embryo, larva, and adult | 29 | |
| 5726221819 | Embryonic Lethals | mutations w/ phenotypes -> death at embryonic/low rate stage | 30 | |
| 5726221820 | Maternal Effect Gene/Egg-Polarity Genes | gene that, when mutant in mother, results in mutant phenotype in offspring -> generally embryonic lethals | 31 | |
| 5726221821 | Bicoid (two-tailed) | -mutant gene causes lack of front half of body and posterior structure at both ends -essential for setting anterior end |  | 32 |
| 5726221822 | Morphagen | gradients for substances that establish embryos axis and more | 33 | |
| 5726221823 | Oncogenes | -cancer-causing genes formed by: -movement of DNA within genome -amplification of proto-oncogene -point mutations in control element/proto-oncogene | 34 | |
| 5726221824 | Proto-Oncogenes | -normal versions of cellular genes -code for proteins that stimulate normal cell growth and division | 35 | |
| 5726221825 | Tumor-Supressor Genes | -prevent uncontrolled cell growth -repair damaged DNA -control cell anchorage (absent in cancers) | 36 | |
| 5726221826 | Cell Cycle Stimulating Pathway | 1. triggered by growth factor binding to receptor in plasma membrane 2. signal relayed to Ras protein to cascade of protein kinases 3. Ras activated by binding to GTP 4. Ras passes signal to series of protein kinases 5. last kinase activates transcription activator |  | 37 |
| 5726221827 | Ras Protein | G protein that relays signal from growth factor on plasma membrane | 38 | |
| 5726221828 | Cell cycle Inhibiting Pathway | 1. DNA damage intracellular signal passed via kinases -> activation of p53 2. p53 promotes transcription of gene for protein-inhibits cell growth -> ensures damaged DNA not replicated |  | 39 |
| 5726221829 | p53 | tumor suppressor gene that codes for specific transcription factor protein that promotes synthesis of cell cycle | 40 | |
| 5726221830 | Mutation Effects | -result in cell cycle overstimulated -not inhibited normally | 41 |
