bio3 - control of gene expression
TRANSCRIPT
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Control of Gene ExpressionThe lac and trp Operons
Figures taken from Campbell 9th Ed.
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jobert.blogspot.com
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www.invitrogen.com
Simultaneous detection of expression of five genes in a whole mount Drosophila embryo
by fluorescence in situ hybridization (FISH) with five RNA probes.
What is meant by gene expression?
What does this picture show us about gene expression?
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lindysglutenfree.wordpress.com, www.tinda.ph, www.energytimes.com, www.personal.psu.edu, www.uoguelph.ca
Picture an E. colicell living in your intestine
Bacteria tune their metabolism to changing environments. How?
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The lac Operon Terms:- activerepressor
- DNA
- lacI
- lacZ
- mRNA
- operator
- promoter
- protein
- regulatory
gene
- RNA
polymerase
Xwww.uoguelph.ca, www.123rf.com
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The lac Operon
Terms:
allolactase (inducer), -galactosidase, DNA, inactive
repressor, lacA, lacI, lacoperon, lacY, lacZ, mRNA,
permease, protein, RNA polymerase, transacetylase
The lac operon is an
inducible operon.
Why
group
these
genes?
Who discovered the
operon model for
gene expression?
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The trp Operon
Cells can adjust
the activity ofenzymes that
are already
present. Cells can adjust
the production
level of
enzymes.
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The trp Operon
Xwww.daviddarling.info, www.123rf.com
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The trp Operon
The trp operon is an
repressible operon.
www.daviddarling.info, www.123rf.com
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Negative Gene Regulation
Repressible Inducible
Anabolic Catabolic
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Positive Gene Regulation
...how does E. coliknow which
energy source to use?
lindysglutenfree.wordpress.com, www.mycutegraphics.com, www.tinda.ph
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