BOLOGY 107 Lecture 28 Outline of Last Lecture I DNA Replication a Polymerases b Proofreading c Eukaryote problem II Gene Expression a Central Dogma b Transcription Outline of Current Lecture III Gene Expression a Transcription cont b RNA Processing c Translation Current Lecture Gene Expression 1 Transcription cont a Uses ribonucleotides replace thymine with uracil b DNA strands separate into the template strand and the coding strand c Initiation i Transcriptions factors bind to DNA at specific sequence where RNA synthesis is to begin 1 Sequence is referred to at the promoter ii Bound factors load on RNA Polymerase II 1 Seperates DNA and starts synthesis d Elongation i Similar process as DNA Pol III just using ribonucleotide triphosphate 1 Instead of thymine adenine is paired with uracil ii RNA is separated DNA re associates iii Topoisomerase is still used e Termination i Disruption is transcription complex 1 Bacteria have two ways to disrupt 2 Eukaryotes have one way to disrupt 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 2 RNA processing a Mostly in eukaryotes i Product of transcription is pre mRNA 1 Needs modified before it leaves the nucleus ii Occurs contemporaneous with transcription iii Modifications 1 5 cap added an extra methylated guanine is added to the 5 end 2 3 poly andenylation a large amount of adenines are added to the 3 end 3 Intron splicing sections of the middle are removed leave exons a Done by splicosome i Uses sequence specific base pairing to recognize the sequences to be removed b Done to create variability i More than one protein can be created off of one gene c Acts as a form of error recognition d Evolution recombine protein domains i Domains in proteins distinguish functions 1 Exons code domains 2 Allows for molecular protein construction a Remove or leave domains trough splicing b Cross over errors bring new domains together to form new proteins iv mRNA structure after 1 5 cap 5 UTR un translated region start codon code sequence stop codon 3 UTR poly A tail 3 Translation a Genetic code mRNA is read in sets of three to form codons i Codons code for amino acid some codons code for the same acid 1 Start AUG 2 Stop UAA UAG or UGA b Carried out by ribosome i mRNA read by ribosome ii tRNA transfer to bridge mRNA to amino acid made of anti codons iii rRNA ribosomal performs enzymatic function within ribosome
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