Lecture 20 Review Replication how to make more DNA Players DNA Polymerase primase helicase ligase topa Fidelity high Start leading strand and lagging strand origin of replication Direction Direction Template Read 5 3 Direction Molecule Made 3 5 Transcription RNA out of DNA not all parts of genome get converted Players RNA polymerase Fidelity not as high as replication Start Promoter Direction Direction Template Read 3 to 5 Direction Molecule Made 5 to 3 Translation mRNA to Protein Players Ribosome tRNA Fidelity not as high as replication Start AUG start codon Direction Template Read 5 to 3 Direction Molecule Made N terminal to C terminal Gene Regulation How When to transcribe Genes that are needed Repressed Remove repression Not expressed when not needed Activate when needed Gene Localization How proteins know where to go ER localization signal will get tethered n terminal No cytosol Transmembrane domain in protein end up in plasma membrane if not then will be secreted N terminal will face outside because topologically similar switches for following protein Viruses strand mRNA like can be translated by ribosome strand needs to be converted to two important groups ssRNA only replicate in RNA form never need to go to RNA to DNA if virus gets inserted into genome need to be converted to DNA reverse transcriptase retrovirus Replication ssRNA make a complementary strand RNA directed RNA pol mRNA now can be translated into viral proteins can t encode have to shoot into host cell ssRNA retroviruses reverse transcriptase could code for some will shoot into host cell if not a retrovirus and just uses ribosomes and goes straight to proteins dsDNA inject genome into the host cell don t need to bring along polymerases ssDNA either transcribed directly or replicated into dsDNA then transcribed RNA directed DNA pol DNA now can be inserted into the genome integration and lysogenic cycle Cancer oncogenes uncontrolled cell division loss of tumor surpressor
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