BIOL 1107 1nd Edition Lecture 23 Outline of Current Lecture I Mis sense mutation II Non sense III Silent IV Frameshif V Deletion Outline of Current Lecture I Gene Expression Prokaryotic II Gene Regulation III Terminology IV Gene Expression Eukaryotic Current Lecture I Gene Expression II National Human Genome Research Institute o How many genes in the human body 24 000 genes o Every single cell has these genes Gene Expression two classes of genes o Housekeeping always expressed cellular respiration actin microtubules for shape o Regulated genes melanin digestive enzymes Gene Regulation How do we regulate genes DNA binding proteins TATA binding proteins Turning a gene on positive regulation Turning a gene off negative regulation 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 Tryptophan essential amino acid get it from food o E coli can make their own tryptophan How do cells control multiple genes at the same time o Prokaryotes operons Trp operon Why would the cell want to stop tryptophan synthesis Too much tryptophan activates repressor which stop RNA synthesis How is this operon regulated Lac operon III Lactose utilization Lac operon negative and positive regulation Sensing glucose levels presence of glucose turns lac operon off no presence of glucose turns lac operon on When glucose is low When glucose is high Under what conditions will bacteria strongly express lac operon In the presence of lactose but not glucose Terminology Negative regulation repressor protein stopping blocking transcription IV Repressor binds to the operator and blocks attachment of RNA polymerase to the promoter preventing transcription of the genes Co repressor a small molecule that cooperates with a repressor protein to switch an operon off Positive regulation turning on of the structural gene expression by the active repressor protein Activator a protein that binds to DNA and stimulates transcription of a gene Co activator a protein that increases gene expression by binding to an activator or transcription factor which contains a DNA binding domain The co activator is unable to bind DNA by itself Inducer inactivates the repressor Eukaryotic Gene Expression Regulation occurs at many levels DNA packaging o Histones nucleosomes protein scaffold DNA protein scaffold chromatin o Heterochromatin very tightly packed o Euchromatin loosely packed has more gene expression Why Easier to get to Transcriptional control Post transcriptional control o Protein processing protein longevity
View Full Document
Unlocking...