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The map of the lac operon is: POZY The promoter (P) region is the start site of

ID: 51769 • Letter: T

Question

The map of the lac operon is:    POZY  

     The promoter (P) region is the start site of transcription through the binding of RNA polymerase before actual mRNA production. Mutationally altered promoters (P-) cannot bind RNA polymerase. Certain predictions can be made about the effect of P- mutations. Use your predictions and your knowledge of the lactose system to complete the following table. Insert a “+” where an enzyme is produced and a “-“ where no enzyme is produced. The first one has been done as an example.

Beta-galactosidase

Permease

No lactose

Lactose

No lactose

Lactose

I+P+O+Z+Y+/I+P+O+Z+Y+

-

+

-

+

I+P+O+Z-Y+/I+P-OCZ+Y+

I+P+O+Z+Y+/I+P+OCZ+Y-

I-P-O+Z+Y+/I-P+OCZ-Y+

I+P+O+Z+Y+/I+P+O+Z+Y+

I-P+OCZ+Y-/I+P+O+Z-Y+

I-P-O+Z+Y+/I+P+O+Z-Y+

ISP+O+Z+Y-/I+P+O+Z-Y+

I+P+O+Z+Y-/I+P+O+Z+Y-

Beta-galactosidase

Permease

No lactose

Lactose

No lactose

Lactose

I+P+O+Z+Y+/I+P+O+Z+Y+

-

+

-

+

I+P+O+Z-Y+/I+P-OCZ+Y+

I+P+O+Z+Y+/I+P+OCZ+Y-

I-P-O+Z+Y+/I-P+OCZ-Y+

I+P+O+Z+Y+/I+P+O+Z+Y+

I-P+OCZ+Y-/I+P+O+Z-Y+

I-P-O+Z+Y+/I+P+O+Z-Y+

ISP+O+Z+Y-/I+P+O+Z-Y+

I+P+O+Z+Y-/I+P+O+Z+Y-

Explanation / Answer

Beta-galactosidase

Permease

No lactose

Lactose

No lactose

Lactose

I+P+O+Z+Y+/I+P+O+Z+Y+

-

+

-

+

I+P+O+Z-Y+/I+P-OCZ+Y+

-

-

-

+

I+P+O+Z+Y+/I+P+OCZ+Y-

-

+

-

-

I-P-O+Z+Y+/I-P+OCZ-Y+

+

+

-

-

I+P+O+Z+Y+/I+P+O+Z+Y+

-

+

-

+

I-P+OCZ+Y-/I+P+O+Z-Y+

+

+

+

+

I-P-O+Z+Y+/I+P+O+Z-Y+

+

+

+

+

ISP+O+Z+Y-/I+P+O+Z-Y+

-

-

-

-

I+P+O+Z+Y-/I+P+O+Z+Y-

-

+

-

-

Beta-galactosidase

Permease

No lactose

Lactose

No lactose

Lactose

I+P+O+Z+Y+/I+P+O+Z+Y+

-

+

-

+

I+P+O+Z-Y+/I+P-OCZ+Y+

-

-

-

+

I+P+O+Z+Y+/I+P+OCZ+Y-

-

+

-

-

I-P-O+Z+Y+/I-P+OCZ-Y+

+

+

-

-

I+P+O+Z+Y+/I+P+O+Z+Y+

-

+

-

+

I-P+OCZ+Y-/I+P+O+Z-Y+

+

+

+

+

I-P-O+Z+Y+/I+P+O+Z-Y+

+

+

+

+

ISP+O+Z+Y-/I+P+O+Z-Y+

-

-

-

-

I+P+O+Z+Y-/I+P+O+Z+Y-

-

+

-

-