17.1 Protein Essay

17.1 Genes specify proteins via transcription and translation * George Beadle and Edward Tatum worked together with mutated (Neurospora crass) bread mold to figure out that they were missing a specific enzyme (gene) that catalyzed and synthesized a pathway required. They concluded that they were missing that enzyme because it was lacking the amino acid that coded for the enzyme, thus was mutated and incapable of growing. Led to the one enzyme-one gene hypothesis.
The Products of Gene Expression: A Developing Story * Revisions made: not all proteins are enzymes * Because proteins that are not enzymes are nevertheless gene products, molecular biologists began to think in terms of one gene-one protein. * Beadle and Tatum’s idea was restated as “one gene-one polypeptide hypothesis.” * BUT: many eukaryotic genes can each
Elongation of the RNA Strand * The congregation of many polymerase molecules simultaneously transcribing a single gene increases the amount of mRNA transcribed from it, which helps the cell make the encoded protein in large amounts. * A single gene can be transcribed simultaneously by several molecules of RNA polymerase following each other like trucks in a convoy. * The enzyme adds nucleotides to the 3’ end of the growing RNA molecule as it continues along the double helix. In the wake of this advancing wave of RNA synthesis, the new RNA molecule peels away from its DNA template, and the DNA double helix re-forms.
Termination of