Question

The map of the lac operon and repressor gene is presented

   here:

                                                I     POZYA

P is the promoter; O is the operator; Z encodes ß-galactosidase;

Y encodes lactose permease; A encodes a transacetylase.

The genotypes of merodiploids are shown below.  For each one, choose the correct phenotype from the table below.  (The same phenotype can be chosen for more than one genotype)

PHENOTYPE

                         ß-Galactosidase

            No lactose                                with lactose

A)                    -                                               +

B)                    -                                               -

C)                    +                                              +

D)                    +                                              -

I^--P⁺O^CZ⁺/I⁺P^--O⁺Z^--

Select one:

a. A

b. B

c. C

d. D

The map of the lac operon and repressor gene is presented

   here:

                                                I     POZYA

P is the promoter; O is the operator; Z encodes ß-galactosidase;

Y encodes lactose permease; A encodes a transacetylase.

The genotypes of merodiploids are shown below.  For each one, choose the correct phenotype from the table below.  (The same phenotype can be chosen for more than one genotype)

PHENOTYPE

                         ß-Galactosidase

            No lactose                                with lactose

A)                    -                                               +

B)                    -                                               -

C)                    +                                              +

D)                    +                                              -

I^SP^--O⁺Z⁺/I^--P⁺O⁺Z⁺

Select one:

a. A

b. B

c. C

d. D

The map of the lac operon and repressor gene is presented

   here:

                                                I     POZYA

P is the promoter; O is the operator; Z encodes ß-galactosidase;

Y encodes lactose permease; A encodes a transacetylase.

The genotypes of merodiploids are shown below.  For each one, choose the correct phenotype from the table below.  (The same phenotype can be chosen for more than one genotype)

PHENOTYPE

                         ß-Galactosidase

            No lactose                                with lactose

A)                    -                                               +

B)                    -                                               -

C)                    +                                              +

D)                    +                                              -

I⁺P⁺O^CZ⁺/I^SP^--O⁺Z⁺

Select one:

a. A

b. B

c. C

d. D

Answer 1

Ans-1- I--P+OCZ+/I+P--O+Z--

the operator mutation is constitutive it means beta-galactosidase will be synthesized in the presence as well as in the absence of lactose. So option C is correct.

Ans-2-  ISP--O+Z+/I--P+O+Z+

The mutation of regulatory element code for super repressor that blocks the transcription of genes in the presence as well as in the absence of lactose. So beta-galactosidase will not get synthesized in any condition. option B is correct.

Ans-3-  I+P+OCZ+/ISP--O+Z+

the operator mutation is constitutive it means beta-galactosidase will be synthesized in the presence as well as in the absence of lactose. Option C is correct