Bio 201 1st Edition Lecture 36Outline of Last Lecture I. Eukaryotic mRNA processingA. SplicingB. 5’ CappingC. PolydenylationOutline of Current LectureI. Cracking The CodeA. Is Genetic Code Overlapping?B. How many Nucleotides for an Amino Acid?Current LectureI. Cracking The Code-How is the genetic code organized?-How many nucleotides code for an amino acid?-What is the code?A. Is Genetic Code Overlapping? Prediction: If the code is overlapping, single nucleotide mutations will alter multiple amino acids. If the code is non-overlapping, single nucleotide mutations will alter one amino acid. -1960 experiment- Tsugita and Fraenkel-Conrat- Chemically mutagenized tobacco mosaic virus single nucleotide (point) mutation. RESULT: Non-overlapping, Single nucleotide mutation only 1 amino acid changed. B. How Many Nucleotides Code for an Amino Acid? These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Crick- 1961 tried to infect E. coli T4 becteriophage. RESULT: 1,2 or4 insertions T4 does not infect E. coli. But 3 insertions T4 usually infects E. coli. -This is because there are 3 nucleotides per 1 amino acid, each code is 3 letters. For example- AGT TTA CAT.-Deletion or insertion of 1,2, or 4 nucleotides shifts the reading frame of DNA/RNA such that all the downstream amino acid sequences are altered: Frameshift mutations.-Deletion or insertions of 3 nucleotides amino acid sequence downstream of 3rd mutations
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