Beta Galactosidase Report
Title:
Investigation of Induction Time of lac operon in E. Coli with IPTG, and Comparision of the Amount Beta-galactosidase produced with Lactose, IPTG and Antibiotic.
Abstract:
Introduction:
An operon is a group of genes that are arranged side by side with a regulatory gene. It also includes a promoter gene, operator gene, structural genes. Regulatory genes control transcription with positive or negative signal. (Jacob, and Monod, 1961) A positive signal, inducer, would stimulate binding of RNA polymerase by binding to the operator gene and transcription would occur. A negative signal, repressor, would not have any transcription occurring as it would not allow RNA polymerase to bind to promoter. This control of gene expression allows organism to not waste energy producing enzymes not needed. (Murray, 2012)
The lac operon has a promoter, operator, regulatory and structural genes. The structural genes consists of the lacZ, lacY and lacA gene which codes for enzymes beta-galactosidase, permease and thiogalactoside transacetylase respectively. (Campbell and Farrell, 2009) Lactose is dissacharide with galactose and glucose binded together by a glycosidic linkage. Beta-galactosidase hydrolyses that linkage, hence breaks down lactose to be used as a carbon source. (Campbell et al, 2009) Permease is a membrane-transport protein, it goes against the membrane potential concentration gradient to drive lactose into cell. (Kaback, Sahin-Toth and Weinglass, 2001) The function of thiogalactoside transacetylase is still being studied but there seems to be a connection defending the cell against antibiotics. (Andrews and Lin, 1976) The regulatory gene is called the lacI gene, it produces the repressor which causes the negative control for gene expression. (Murray, 2012)
The lac operon transcription occurs only when there is no repressor bound to the operator and when the cAMP.CAP complex is bound to the promoter. In levels of high glucose, cyclic AMP
Investigation of Induction Time of lac operon in E. Coli with IPTG, and Comparision of the Amount Beta-galactosidase produced with Lactose, IPTG and Antibiotic.
Abstract:
Introduction:
An operon is a group of genes that are arranged side by side with a regulatory gene. It also includes a promoter gene, operator gene, structural genes. Regulatory genes control transcription with positive or negative signal. (Jacob, and Monod, 1961) A positive signal, inducer, would stimulate binding of RNA polymerase by binding to the operator gene and transcription would occur. A negative signal, repressor, would not have any transcription occurring as it would not allow RNA polymerase to bind to promoter. This control of gene expression allows organism to not waste energy producing enzymes not needed. (Murray, 2012)
The lac operon has a promoter, operator, regulatory and structural genes. The structural genes consists of the lacZ, lacY and lacA gene which codes for enzymes beta-galactosidase, permease and thiogalactoside transacetylase respectively. (Campbell and Farrell, 2009) Lactose is dissacharide with galactose and glucose binded together by a glycosidic linkage. Beta-galactosidase hydrolyses that linkage, hence breaks down lactose to be used as a carbon source. (Campbell et al, 2009) Permease is a membrane-transport protein, it goes against the membrane potential concentration gradient to drive lactose into cell. (Kaback, Sahin-Toth and Weinglass, 2001) The function of thiogalactoside transacetylase is still being studied but there seems to be a connection defending the cell against antibiotics. (Andrews and Lin, 1976) The regulatory gene is called the lacI gene, it produces the repressor which causes the negative control for gene expression. (Murray, 2012)
The lac operon transcription occurs only when there is no repressor bound to the operator and when the cAMP.CAP complex is bound to the promoter. In levels of high glucose, cyclic AMP