BIO 112 Lecture Notes - Lecture 22: Chromosome, Catabolite Activator Protein, Lac Operon
16 Oct 2015
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Document Summary
Operator mutants: constitutative mutants mean the system will always be turned on. Cis-acting means that they only effect genes on the same chromosome. Cis-acting operator (operator is a portion of the sequence of dna so it cannot move) with a trans-acting protein because proteins can move and bind to any number of operators. Iptg: similar to lactose that can bind to the protein but different enough not to be broken down. The promoter region is essential for the binding of rna polymerase. Promotor mutations are cis-acting and they only effect downstream adjacent genes. An active repressor blocks the expression of a, b and c. A functional activator is required for gene expression of x, y and z. The presence of glucose catabolism results in lac operon repression. Another aspect of regulation is known: a form of positive control necessary camp is produced in times of stress (glucose starvation).
