Techniques for the Investigation of Lac Operons

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The micro-organism used in this lab was E.coli, which is a prokaryote. In general, prokaryotes are small, compact genomes that have a single, round DNA molecule. The genes are tightly packed, with almost no space between them. In the case of E.coli, it has thrA, 1 nucleotide, thrB, thr C.

Enzymes of a single biochemical pathway are coded by the operon: introns are absent, so all genes are not interrupted and the sequence is non-repetitive. An operon is a group of adjacent genes which are transcribed as a unit into a single polycistronic mRNA molecule. The lac operon is necessary for the transportation and metabolism of lactose.

An operon is made up of three features: promoter, operator and structural genes. The promoter site is where the RNA polymerase (Plac) is attached. The operator is the site where repressor protein binds, blocking RNA polymerase from binding, which in turn stops the transcription of the operon. Lastly, there are the structural genes, which are numerous genes, which code for the enzymes of a metabolic pathway, transcribing as a unit.

There are two techniques ...

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