HTHSCI 1LL3 Lecture Notes - Lecture 13: Lipid Bilayer, Cell Membrane, Amylase
22 Jun 2018
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GENE EXPRESSION
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Eukaryotic Gene Expression
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Only certain genes are transcribed in the cells of each type of tissue
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There are differences in gene expression at different life stages
•There are several different ways to regulate expression
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cats with patches
>colours are on Xchromosomes .:females have patches
>black colour is where the Orange patches are silenced
Adaptation +Specialization
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Its advantageous to prokaryotes +eukaryotes to regulate gene activity
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helps cells adapt to changes in their environment + helps eukaryotic cells in special Ration
>Bacteria expressing genes to use different food sources
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helps save cells energy since transcription +translation consume alot of energy
>Not all genes expressed at the Jame time to save energy
Prokaryotic Gene Expression
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Prokaryote genes that code for proteins with similar lnnctions are grouped together and
are Under control of a single promoter
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Operon :bacterial promoter ,where all genes are expressed together (all ON or OFF )
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Genes In an Open hare transcribed into apoly astnniu mRNA with aStart t stop codon
structural gene
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Protein products may all be participants In same biosynthetic pathway
•RNA polymerase binds to the promoter upstream of the coding regions and this promoter
Control transcription of all genes
Repression c- NO
transcription
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in prokaryotes gene expression is controlled at transcription occurs
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transcription is controlled by the ability of RNA polymerase to bind to promoter No Proteins
Produced
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repressors :regulatory proteins that prevent the polymerase from binding +
Initialing transcription lneqahm control )
Induction
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lnauun "small molecules Inutrients )that bind to the repressor ,changing Its conformation and
making It unable to bind to the operator
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Once inducer inactivates the repressor,RNA Polymerase can bind +transcription can proceed
Document Summary
Only certain genes are transcribed in the cells of each type of tissue. There are differences in gene expression at different life stages. There are several different ways to regulate expression cats with patches colours are on. X chromosomes females have patches black colour is where the. Its advantageous to prokaryotes + eukaryotes to regulate gene activity helps cells adapt to changes in their environment. Bacteria expressing genes to use different food sources helps save cells energy since transcription + translation consume a lot of energy. Prokaryote genes that code for proteins with similar lnnctions are grouped together and. Operon : bacterial promoter , where all genes are expressed together ( all on or off ) Genes in an open h are transcribed into a poly astnniu mrna with a. Protein products may all be participants in same biosynthetic pathway. Rna polymerase binds to the promoter upstream of the coding regions and this promoter.
