The map of the lac operon is POZY. The promoter (P) region is thestart site of transcription through the binding of the DNApolymerase molecule before actual mRNA production. Mutationallyaltered promoters (P -) apparently cannot bind the RNA polymerasemolecule. Certain predictions can be made about the effect of P -mutations. Use your predictions and your knowledge of the lactosesystem to complete the following table. Insert a â+â where andenzyme is produced and a â-â where no enzyme is produced. The firstone has been done as an example.Ã-Galactosidase PermeaseGenotype No lactose Lactose No lactose Lactosea. I- P+ OC Z+ Y- / I+ P+ O+ Z- Y+b. I+ P- OC Z- Y+ / I- P+ OC Z+ Y-e. I- P+ OC Z+ Y- / I- P+ O+ Z- Y+f. I- P- O+ Z+ Y+ / I- P+ OC Z+ Y-Could you guys explain one of them? (a, b, e, f)

OneClass: The map of the lac operon is POZY. The promoter (P) region is thestart site of transcriptio...

1. The following shows the genotype of a partial diploid bacterial cell - where one chromosomal region containing the lac operon in E,coli is given, and the other fragment is from a plasmid carrying another lac operon from another source. The two are separated by a slash (/).

The possible answers indicate with a Êº+Êº or a Êº-Êº whether Î²-galactosidase would be expected to be produced at induced levels under two circumstances: 1) first in the absence of lactose and 2) second in the presence of lactose. (Assume that glucose is not present in the medium.)

Genotype C: Is Oc Z+/ FÊ¹ I + O+ Z+
KEY:

I+ = wild-type repressor
I- = mutant repressor (unable to bind to the operator)
Is = mutant repressor (insensitive to lactose)
O+ = wild-type operator
Oc = constitutive operator (insensitive to repressor)

a. +,+ d. -,+

b. -,- e. cannot tell

c. +,-

2. The following shows the genotype of a partial diploid bacterial cell - where one chromosomal region containing the lac operon in E,coli is given, and the other fragment is from a plasmid carrying another lac operon from another source. The two are separated by a slash (/).

The possible answers indicate with a Êº+Êº or a Êº-Êº whether Î²-galactosidase would be expected to be produced at induced levels under two circumstances: 1) first in the absence of lactose and 2) second in the presence of lactose. (Assume that glucose is not present in the medium.)

Genotype D: I- O+ Z+/ FÊ¹ I- O+ Z+
KEY:

I+ = wild-type repressor
I- = mutant repressor (unable to bind to the operator)
Is = mutant repressor (insensitive to lactose)
O+ = wild-type operator
Oc = constitutive operator (insensitive to repressor)

a. +,+ d. -,+

b. -,- e. cannot tell

c. +,-

3. The following shows the genotype of a partial diploid bacterial cell - where one chromosomal region containing the lac operon in E,coli is given, and the other fragment is from a plasmid carrying another lac operon from another source. The two are separated by a slash (/).

The possible answers indicate with a Êº+Êº or a Êº-Êº whether Î²-galactosidase would be expected to be produced at induced levels under two circumstances: 1) first in the absence of lactose and 2) second in the presence of lactose. (Assume that glucose is not present in the medium.)

Genotype E: I + O+ Z+/ FÊ¹ I + O+ Z+
KEY:

I+ = wild-type repressor
I- = mutant repressor (unable to bind to the operator)
Is = mutant repressor (insensitive to lactose)
O+ = wild-type operator
Oc = constitutive operator (insensitive to repressor)

a. +,+ d. -,+

b. -,- e. cannot tell

c. +,-

ceruleantiger445

1. The following shows the genotype of a partial diploid bacterial cell - where one chromosomal region containing the lac operon in E,coli is given, and the other fragment is from a plasmid carrying another lac operon from another source. The two are separated by a slash (/).

The possible answers indicate with a Êº+Êº or a Êº-Êº whether Î²-galactosidase would be expected to be produced at induced levels under two circumstances: 1) first in the absence of lactose and 2) second in the presence of lactose. (Assume that glucose is not present in the medium.)

Genotype A: I + O+ Z+/ FÊ¹ I - O+ Z+

KEY:

I+ = wild-type repressor
I- = mutant repressor (unable to bind to the operator)
Is = mutant repressor (insensitive to lactose)
O+ = wild-type operator
Oc = constitutive operator (insensitive to repressor)

a. +,+ d. -,+

b. -,- e. cannot tell for certain

c. +,-

2. The following shows the genotype of a partial diploid bacterial cell - where one chromosomal region containing the lac operon in E,coli is given, and the other fragment is from a plasmid carrying another lac operon from another source. The two are separated by a slash (/).

The possible answers indicate with a Êº+Êº or a Êº-Êº whether Î²-galactosidase would be expected to be produced at induced levels under two circumstances: 1) first in the absence of lactose and 2) second in the presence of lactose. (Assume that glucose is not present in the medium.)

Genotype B: I - Oc Z+/ FÊ¹ I - O+ Z-

KEY:

I+ = wild-type repressor

I- = mutant repressor (unable to bind to the operator)
Is = mutant repressor (insensitive to lactose)
O+ = wild-type operator
Oc = constitutive operator (insensitive to repressor)

a. +,+ d. -,+

b. -,- e. cannot tell for certain

c. +,-

beigecaribou308

1. The lac operon of E. coli controls the expression of genes that code for enzymes involved in lactose metabolism. The operon system is inducible in that it can be âturned onâ by the presence of lactose. Mutations to various regions of the lac operon have been discovered which affect both the control of gene expression and the function of the gene products.

These mutations include:

I ^- = produces a repressor protein that can not bind to the operator region

I ^s = produces a repressor protein that can not be removed from the operator region

O ^C = can not bind a repressor protein

Z ^- = produces a defective (non-functioning) Î²-galactosidase enzyme

( I^- are recessive to I⁺; I⁺ recessive to I^S )

Detail the functionality of the lac

operon under the following genetic and cellular conditions.

GENES	Lactose present	Repressed (yes/no)	Constitutive (yes/no)	Inducible (yes/no)
I + O + Z +	no
I + O C Z +	no
I S O + Z +	yes
I - O + Z +	yes
I S O C Z +	no

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