DNA is the master blueprint set of directions that everyone has to follow Transcription and translation are happening at the same time in prokaryotic cells Transcription and translation does not happen at the same time in eukaryotic cells making proofreading happen Add more steps Everything is moving in a single direction Central Dogma DNA RNA Protein Transcription Txn DNA mRNA Translaiton Tln mRNA peptide DNA RNA Peptide s Quaternary structure modification phosphorylation Protein Transcription and translation is a one way process Central Dogma of Biology Genes can and DO sometimes overlap splicing of RNA Pre mRNA is unprocessed a raw photocopy of DNA code Prokaryotes naked DNA Transcription and Translation are concurrent Eukaryotes Txn inside nucleus Tln in cytoplasm RNA processing occurs in Eukaryotes only 4 nucleotides 20 amino acids In Bacteria Polyribosome complex of ribosomes that go through transcription and translation at the same time DNA Replication single origin of replication in a genome Compact that triggers transcription and translation What if a mistake is made Codon changes can be made during o DNA Replication o May be silent Wobble redundancy in the 3rd nucleic acid o May change AA Now the detailed tour of transcription and translation o Transcription Point Mutations Single Base Change Transcription 1 Initiation 2 Elongation 3 Termination Initiation Promoter site where the work begins o Eukaryotic Promoter TATA Box does not have to be a TATA box Total of all three classes of players many transcription factors Spacing of TATA box and start codon is important generally 25bp or Transcription Initiation Complex 25bp upstream of ATG Not all promoters are TATA boxes Tells RNA polymerase which way to go upstream and downstream Two Common Promoters o Eukaryotic o Prokaryotic 5 TATAAAA 3 3 ATATTTT 5 5 TTTTATA 3 3 AAAATAT 5 o When vertical left strand mRNA goes from top to bottom right strand mRNA goes from bottom to top o Left strand mRNA going from top to bottom transcription starts after promoter right strand mRNA going from bottom to top transcription starts after promoter not right after just a close distance Worker RNA polymerase making RNA off of the DNA template o Elongation RNA polymerase adds nucleotides to the 3 end of the growing RNA strand It doesn t have to complete its work before a second RNA polymerase starts working Terminator site where the work is stopped o Termination RNA polymerase transcribes a terminator sequence and keeps on going in Eventually the RNA molecule will be cut free from the polymerase just past eukaryotes this terminator Prokaryotes mRNA is ready to be translated Eukaryotes pre mRNA is exported into the cytosol Introns are cut out and exons are spliced together 5 cap and 3 poly a tail is added Pre Translation Processing o 5 Cap o 3 Poly A Tail The mRNA is finished now what Also required o Amino acids o tRNAs o Energy ATP In eukaryotes the mRNA is not ready to leave the nucleus immediately after transcription It is sent out of the nucleus and into the cytoplasm there it will need to meet a ribosome Amino Acid Attachment Site Two dimensional Structure Certain parts are connected by hydrogen bonds Contains anticodon area Aminoacyl tRNA Synthetase Enzyme AMP charges the tRNA that will make an active tRNA and amino acid Schematic model showing binding sites A Site Aminacyl tRNA Biding Site P Site Peptidyle tRNA Binding Site E Site Exit Site Initiation 5 cap and other sequences help ID where All starts with a methionine Met Initiator tRNA binds to the mRNA binding site GTP converts to GDP Large ribosomal subunits comes to make up the translation initiation complex Translation Initiation o Activated tRNA mRNA two subunits of rRNA come together o rRNA recognizes leader segment of mRNA assembles around it o Initiation codon tells rRNA where to add the first AA o Assembling this complex requires energy Supervised by initiation factors proteins Elongation Termination o Addition of each AA to the growing polypeptide chain dehydration synthesis o Ratcheting of ribosome so it continues to move along mRNA requires energy o Loading of new AAs to A site o STOP codon read by rRNA Water consumed in hydrolysis reaction that breaks bond between protein and P site o Polypeptide released from ribosome o Ribosome subunits separate Types of Modifications Proteolysis protein cutting Glycosylation Phosphorylation Possible destinations marked by zip codes which is part of N terminal AA sequence Ribosomes are not permanently attached to rough ER They dock at receptors that recognize the N terminus of the new peptide chain TRANSLATIONAL ERRORS FROM YEAST TO NEW THERAPEUTIC pittcat Primary Literature Original findings including materials and methods IMRAD format o Abstract What was done in a nutshell o Introduction What was the problem o Materials and Methods How was the problem solved o Results What did they find out o Discussion What does it mean o Other Elements Citation Whose word did they refer to Title Abstract Acknowledgements Optional Who helped them out References Appendices Optional Extra information Good papers are in peer reviewed journals Authors o First Author most of the grunt work undergraduate graduate student o Middle Authors doing a portion or some part of the lab o Last Authors head of the lab primary investigator Title and Abstract Information dense Details instead of drama Is Bambi killing the forest Introduction vs Abstract Introduction o Context perplexity resolution in funnel format o Sets the reader up for the rest of paper by defining the topic area and specific problem o Contains references to other sources Materials and Methods Reagents Times temperature organisms Techniques used Controls Just the facts What was seen Results NOT what it means Figures tables galore 50 greater mortality at Dosage X when compared to the control Tables Data grids Self explanatory when combined with title Figures Get captions Why yeast Saccharomyces cerevisiae B20 22 in back or text Images maps charts graphs anything that is not a data grid S cerevisiae Eukaryotic Unicellular Replicate asexually or sexually depending on conditions can exist as haploid or diploid Easy to handle and manipulate no ethics issues Genome sequence finished 1997 Introduction errors Review of ribosome units accuracy or translation benefits to recoding controlled o 1 products from single mRNA o Common with viruses as they hijack cell cycle o Production of replicases enzymes that
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