Beta Galactosidase Lab Report

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The expression of lac operon in each tube equals the amount of beta-galactosidase produced. Therefore, by looking at the amount of beta-galactosidase under different conditions collectively is a good way to understand the function of inducers and repressors in supervising the expression of lac operon and the control of gene expression generally.
At the given time sets, CTAB was added to the tubes to kill the E. coli cells and lyse the cells to release its contents including galactosidase enzyme.
We can measure the amount of beta galactosidase produced in each tubes indirectly although it is difficult. ONPG is converted to galactose and o-nitrophenol by beta-galactosidase which has a yellow color with an absorbance at 414nm. The amount of ONPG …show more content…

coli after addition of inducer IPTG at different times. We can see from the graph that it does not cut the X axis at time 0. This is due to the fact that the lac operon was not induced by IPTG due to lack of time. The graph cuts the X axis at roughly 1 and a half minutes after adding IPTG. This indicates the time where lac operon was first induced because there was beta-galactosidase produced. From here we can deduce that production of beta-galactosidase does not take place immediately after adding IPTG but rather takes a while for all the expression staged to be passed by lac operon in order to produce beta galactosidase. From the graph we can see that for the control no beta galactosidase was produced. This is because the control contains water and the repressor was allowed to bind to the operator, causing the transcription process to initiate due to RNA polymerase II not binding to the operator. There is a positive linear relationship between the time of induction with IPTG and the amount of beta-galactosidase production in the tubes. IPTG acts as an inducer, stopping the repressor protein to bind to the operator region by binding to the repressor protein, This causes the lac operon to be

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