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6 Cards in this Set
- Front
- Back
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Beadle and Tatum's hypothesis |
it was found that the mutants lacked an enzyme in the metabolic pathway that produced some molecule that the mold needed(an aminoacid). They also showed that each mutant was defective in a single gene and accordingly postulated the hypothesis of one gene-one enzyme. |
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One gene one polypeptide |
First it was extended to one gene one protein. Then it was discovered that many proteins consist of two or more different polypeptide chains and each polypeptide may be specified by its own gene. That is Beadle and Tatum’s hypothesis has come to be restated as one gene-one polypeptide. |
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Transcription terminator |
a section of nucleic acid sequence that marks the end of a gene or operon in genomic DNA during transcription. |
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Promoters and terminator |
transcription starts at a specific point of the gene in the length of the DNA and ends at a specific point of the gene (see figs. bellow), known as promoters and terminators respectively. |
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RNA Splicing |
e first step of procesing is called splicing, which the removal of all the introns and the exons are spliced together as a continuous coding sequence for the proteins. Splicing occurs by two mechanisms; •1. Catalysed by a complex of proteins and small RNA molecules •2. Catalysed by the mRNA transcript itself acting as an enzyme |
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Lastly |
Events that occur during or following biosynthesis include proteolysis, post-translational modification and protein folding. Proteolysis may remove N-terminal, C-terminal or internal amino-acid residues or peptides from the polypeptide. The termini and side-chains of the polypeptide may be subjected to post-translational modification. These modifications may be required for correct cellular localisation or the natural function of the protein. During and after synthesis, polypeptide chains often fold to assume, so called, native secondary and tertiary structures. This is known as protein folding and is typically required for the natural function of the protein |
