parts_of_ch_10_and_12_spr09

parts_of_ch_10_and_12_spr09 - Selected topics from chapter...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Selected topics from chapter 10 and 12 Chapter 10- Molecular Regulation Regulating Gene Expression Microbes respond to changing environments Alter growth rates Alter proteins produced Must _sense_ their environment _Receptors_ on cell _surface_ Must _transmit information_ to chromosome Alter gene expression Change transcription site Change translation site Sensing the Environment Two-component signal transduction 1._Sensor kinase_ protein in _plasma membrane____________________ Binds to signal Food Chemical cue Activates itself via phospohorylation 2.Cytoplasmic _response regulator_ Takes phosphate from sensor Binds chromosome Alters _transcription rate_ of multiple genes Altering Transcription Rates sigma factor guides RNA polymerase to initiate transcription at promoter _Proteins_ can help _guide_ sigma factor to _promoter__ Activation _Binds_to DNA sites next to promoter _Increases_ of that genes _transcription__ _Protein__ can _block__ sigma factor from _binding_ Repressor _Binds__ to DNA sites next to promoter o Operator _Lowers frequency__ of that genes _transcription__ The amount of an enzyme in the cell can be controlled by decreasing ( _repression__ ) or increasing ( _induction_ ) the amount of _mRNA_________ that encodes the enzyme For _negative control_ , the regulatory molecule is called a _repressor protein_ and it functions by _inhibiting mRNA synthesis___ The E. coli lac Operon Lactose (_milk sugar) is used as nutrient source Cannot pass through cell membrane _Lactose permease_ allows entry Disaccharide lactose must be cleaved into monosaccharides to be digested _beta-galactosidase cleaves_____ lactose People also make b-galactosidase If not, person is lactose-intolerant The _lacZ gene encodes b-galactosidase The _lacY gene __ encodes lactose permease Need both proteins to digest lactose Operon Multiple genes transcribed from one promoter Both genes are transcribed together _Repressor__ protein _LacI blocks_ transcription Repressor binds to operator Blocks __sigma factor___________ from binding _promoter_ Repressor responds to presence of lactose...
View Full Document

This note was uploaded on 03/31/2009 for the course BIOL 2051 taught by Professor Brininstool during the Spring '07 term at LSU.

Page1 / 12

parts_of_ch_10_and_12_spr09 - Selected topics from chapter...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online