BIO 121 Lecture Notes - Lecture 13: Rna Splicing, Start Codon, Intron
23 Mar 2018
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Document Summary
The idea of the gene has evolved through the history of genetics. A region of specific nucleotide sequence in a chromosome. A dna sequence that codes for a specific polypeptide chain. (proteins) Special repair enzymes fix incorrectly paired nucleotides. Dna polymerase can only add nucleotides to the 3" end of the strand of dna. Sequence may become permanent and can be passed on to the next generation. These changes are the source of the genetic variation upon which natural selection operates and are ultimately responsible for the appearance of new species. ( mutations , changes in dna, natural selection) Eukaryotic chromosomal dna molecules have special nucleotide sequences at their ends called telomeres. Telomeres do not prevent the shortening of dna molecules, but they do postpone the erosion of genes near the ends of dna molecules. It has been proposed that the shortening of telomeres is connected to aging.
