Operon
comparison: similarities
Both
the
Lactose and Arabinose are a group of key nucleotide sequences that are
responsible for synthesizing the enzymes being transcribed. Although
the steps
taken in metabolizing lactose and arabinose is different, the
composition and
main functions of the operons are very similar. It helps to keep
an eye on the general structure of both the operons while considering
the similarities below:
Ø
Both
Operons occur in the bacteria E.coli. (and not in
eukaryotes)
Ø They both contain an operator, a common promoter, and three structural genes. The structural genes encode for proteins.
Ø They also both contain a regulatory protein. The function of the regulatory protein is similar in both. The regulatory protein binds to operator regions in order to repress or activate the transcription of structural genes
Ø The functions of each of the genes in both operons is very similar:
§ The operator region is where the regulatory protein binds
§ The promoter region is where the RNA polymerase binds in order for the transcription to start.
§ The structural genes code for the protein product (in both cases, enzymes).
§ Regulatory gene codes for the regulatory protein.
§ Both operons need inducer (the lactose or arabinose) to turn on the structural genes.
Of course, the differences are significant, but it can be seen
that the general operon model is similar in structure and function
across different types of operons.