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Unformatted text preview: UNIT THREE: GENETICS Chapter Seventeen: From Gen Chapter Seventeen: From Gen Chapter Seventeen: From Gen Chapter Seventeen: From Gen (Text from Biology , 6 th Edition, b Fro THE CO The Study of Metabolic Defects In 1909, Archibald Garrod sugge through enzymes that catalyze How Genes Control Metabolism Research conducted several yea gene dictates the production of that cells synthesize and degrad pathways, in which each chemic enzyme. A breakthrough in demonstratin and Edward Tatum began workin for mutants that differed from t survive in the laboratory on agar mutants that needed certain es They found that their mutants f leading to synthesis of arginine, converted to citrulline, which is showed that the mutants were defective gene, their results pro One Gene-One Polypeptide Researchers later learned that n still gene products, molecular bi many proteins are made of two its own gene. Beadle and Tatum hypothesis hypothesis hypothesis hypothesis. Transcription and Translation Ar Recall that RNA contains ribose usually single-stranded. Transc Transc Transc Transc DNA strand provides a template template for assembling a seque mess mess mess messenger RNA enger RNA enger RNA enger RNA (mRNA mRNA mRNA mRNA), becau ne to Protein ne to Protein ne to Protein ne to Protein by Campbell and Reece) rom Gene to Protein (Chapter Seventeen) ONNECTION BETWEEN GENES AND PROTEINS s Provided Evidence That Genes Specify Proteins ested that genes dictated phenotypes specific chemical reactions in the cell. : One Gene-One Enzyme ars later supported Garrods idea that a f a specific enzyme. Biochemists found de most organic molecules via metabolic ical reaction is catalyzed by a specific ng the relationship between genes and enzymes ing with a bread mold. After treating the mold w the wild-type in their nutritional needs. Wild-ty r mixed with inorganic salts, glucose, and biotin ssential molecules because they couldnt synthes fell into three classes, each mutated in a differen , it was necessary to convert a precursor nutrien s converted to arginine. When they tested the m blocked at different steps in the pathway. Since ovided strong support for the one gene-one enzy not all proteins are enzymes. Since proteins that iologists began to think in terms of one gene-on or more different polypeptide chains, with each ms idea can then be restated as the one gene one gene one gene one gene-o re the Two Main Processes Linking Gene to Prot e instead of deoxyribose, has the base uracil inst cript cript cript cription ion ion ion is the synthesis of RNA under the direct e for DNA synthesis of a complementary strand, ence of RNA nucleotides. This type of RNA mole use it carries a message from the DNA....
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- Spring '08
- AP Biology