Worksheet+11+-+Answer+Key - o Point Mutations Base pair...

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Bio 93 Pooja Patel Worksheet 11 – Lecture 22 Lecture 22: Regulation of Gene Expression Characteristics of Genetic Code o 61 codons coding for 20 amino acids o Unambiguous: Ever codon codes for only one protein o No punctuation: There are no spaces or extra nucleotides between codons o Always starts with an AUG codon o Always sends with a stop codon Summary of Protein Synthesis in a Eukaryotic Cell 1. RNA is transcribed from DNA template. 2. RNA transcript (“pre-mRNA”) is spliced and modified to produce mRNA, which moves from nucleus to cytoplasm. 3. After leaving nucleus, mRNA attaches to ribosome 4. Each amino acid attaches to its proper tRNA with the help of a specific enzyme and ATP 5. tRNAs add their amino acids to the polypeptide chain as the mRNA is moved through the ribosome one codon at a time. When completed, the polypeptide is released from ribosome. Mutations o Changing a single nucleotide in the DNA template strand leads to production of abnormal protein Sickle cell hemoglobin
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Unformatted text preview: o Point Mutations Base pair insertion or deletion Insertions and deletions can also produce frameshift mutations Bio 93 Pooja Patel Worksheet 11 Lecture 22 Regulation of Gene Expression 1. Only a small fraction of genes in the genome are expressed in any given cell 2. Gene expression is primarily regulated by transcription 3. Gene expression is also regulated by steps such as a. RNA processing b. RNA stability/degradation c. RNA translation d. Protein modification e. Protein stability/degradation Regulation of Transcription o TATA and promoter is required to attract RNA polymerase o Enhancers and transcription factors are specific to each other Alternative Splicing o Generating different proteins from the same gene o When introns are spliced out, some exons are kept and others are not Regulation by microRNA (miRNA) o Complementary to mRNA o Binds to mRNA o mRNA is degraded OR translation is blocked...
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This note was uploaded on 12/13/2011 for the course BIOSCI 93 taught by Professor Staff during the Fall '11 term at UC Irvine.

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Worksheet+11+-+Answer+Key - o Point Mutations Base pair...

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