BISC 2539 Lecture Notes - Lecture 11: Lac Repressor, Repressor, Immunoglobulin E
24 Dec 2019
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Bcq howdoesa celldeterminewhich of its thousands ofgene to transcribe. A transcription controlled byregulatoryregion of dna relativelynear the site where transcriptionbegins r some are simple. Twotypesof fundmentalcomponent on1 off switch some complex a shortstretches of dna ofdefinedsequence. Highlyefficientgeneticmechanisms haveevolved into turn transcription of specificgenes onto depending on acellsmetabolicneed forspecificgeneproduct. Responses due to change in the environment 1non environmental regulation of cellular activities t cell division. Bacteriaadaptto their environment byproducingcertain enzymes inducible only whencertainsubstrate present. Anabundance of an endproduct in the environment repressesgeneexpression constitutiveenzymer. Activatorlrepressorsi dnasegment near thepromoter serve asbindingsites for proteins. Itemsrepressorprotein must be prevented from bindingto its target dna site as a necessaryprerequisite for transcription begin. A icef influence allosteric site of regulatoryprotein activitychange. Allosteric effector in lactose metabolism the isomer of sugar lactose aiio acte. se aaaa allostericeffector controls the ability of activator repressor protein to bind to their target. Inpresence of lactose the concentration of the enzymeresponsible for metabolism increase from few thousands percell.
