BIOL201 Lecture Notes - Intron, Spliceosome, Escherichia Coli
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Biology 207 - answers to practice questions 4 - mutations. Question 1 the a-gene makes a pre-mrna with one intron. Make a diagram showing how the pre-mrna is processed normally and what might happen if there is a mutation in the exon/intron boundary. If the exon/intron sequence is absent because of a mutation the spliceosome may either not remove the intron or it might remove it incorrectly using a nearby sequence as an exon/intron boundary. In any case the resulting mature mrna will not have an intact orf. It is unlikely that the truncated proteins made from these mrnas would be functional. Question 2 recall that ems causes gc-->at bp substitutions. Use a diagram to show why or why not. Question 3 the laci gene in e. coli has mutational hot spots. Hot spots are sites in a gene that are much more mutable than other sites. The following sequence is from the middle of the wildtype laci gene: