Question

Complete the table below using to indicate if the enzyme is synthesized and to indicate if the enzyme will not be synthesized. Genotype symbols: Ilacl (the repressor gene): P=Pac (the promoter), O = laco (the operator). Z = lacZ (the B-galactosidase gene), and Y lacy (the permease gene). The minus sign accompanying the symbol (0.g. 1) indicates a mutant gene, the plus sign indicates wild-type/functional gene. O is the constituitive operator mutation (the same as O-) and genes make mutant subunits of the repressor protein (as opposed to which you can think of as not making a product) and P codes for the super-repressor protein, which will not release from the operator. Inducer Absent: B-galactosidase Permcase Inducer Present: B-galactosidase Permease Genotype a. P O ZY b. P+ 0* Z-Y c. P OZY d. P+ 0. Z Y+ e. PPOZY f. PP+ O Z+Y 8. PP+ OZ Y h. +P+ OZ i. 1 P+ 0ZY j. P+ 0+ ZY PP+ 0+Z k. P+ 0* ZY FP+ OZ-Y 1. P+ 0+ Z Y + P+ O+ Z-Y+ m. + P+ Ocz-y- 1 P+ 0* ZY- n. P+ OZ - P+P+ 0+ z-Y 0. PP+ 0* Zor + P O Z+Y+ p. H P - O+ 2+ y- + P+ 0* Z-Y q. ft P- O Z Y- P+P+ O+Z- Y+ I. POZY I POZY s. PO Z. Y I P+ 0* Z-Y t. P+ 0 Z+Y 1 P-02-Y

PLEASE EXPLAIN ANSWERS

Answer 1

	Genotype	Inducer Absent		Inducer Present		Reasoning
		Beta-Galactosidase	Permease	Beta-Galactosidase	Permease
a	I+ P+ O+ Z+ Y+	-	-	+	+	This is a normally functioning Lac Operon.
b	I+ P+ O+ Z- Y+	-	-	-	+	The Beta Galactosidase gene is mutated
c	I+ P+ O+ Z+ Y-	-	-	+	-	The Permease gene is mutated
d	I- P+ O+ Z+ Y+	+	+	+	+	The Lac Repressor is mutated, and the Lac Operon will be constitutively active
e	IS P+ O+ Z+ Y+	-	-	-	-
f	I+ P+ OC Z+ Y+	+	+	+	+	The Lac Operator mutant Oc does not allow Lac Reressor to bind and expression is constitutive.
g	IS P+ OC Z+ Y+	+	+	+	+	The Lac Operator mutant Oc does not allow Lac Repressor to bind and expression is constitutive, despite the presence of the Lac Is mutant.
h	I+ P+ OC Z+ Y-	+	-	+	-	The Oc mutant drives the constitutive expression of the operon, but Permease is mutated.
i	I-d P+ O+ Z+ Y+	+	+	+	+	LacI-d is a mutated Lac Repressor that does not bind to the Operator and allows expression to be constitutive.
j	1-p+o+z+y+ [+P+O+Z-Y-	-	-	+	+	The presence of a single functional copy of LacI can restore the function to Wild-type
k	+X-Z+O+d+I - A+Z+0+d-1	-	-	+	+	Expression is inducible as at least one chromosome carries a functional copy of LacZ and LacY, allowing expression in the presence of Inducer
l	isp+o+z+Y- 1+P+O+z-y+	-	-	-	-	Lac IS is a dominant mutation that will tightly bind to the Operator and will not allow expression of the Operon
m	+P+07-+ 1+P+O+Z+Y-	-	+	+	+	As the Oc operator is cis to a functional LacY, Permease expression is constitutive, while LacZ expression is inducible.
n	I-P+03+Y- 1+P+O+Z-Y+	-	-	-	+	As the only functional copy of LacZ is cis to a mutated Operator, LacZ is constitutively repressed. LacY is inducible as the functional copy of LacY is under a normal promoter/operator.
o	isp+o+z+y+ 1+P+OCZ+Y+	+	+	+	+	As the second chromosome has an Oc operator, the expression of both LacZ and LacY is constitutive.
p	1-dp+o+z+Y- +P+O+Z-Y+.	+	+	+	+	The Lac I-d repressor is a dominant mutation, which does not allow Lac I to bind to the operator and expression is dominant.
q	1+P-09z+y- 1+P+O+Z-Y+	-	-	-	+	No product is produced from the first chromosome as the Promoter is mutated. On the second chromosome, LacZ is mutated and LacY is inducible.
r	+ X-250+d+1 - A+Z+0-d+1	-	+	-	+	No product is produced from the first chromosome as the Promoter is mutated. On the second chromosome, LacZ is mutated and the Oc operator constitutively drives the expression of LacY
s	1-p-o+z+y+ 1+P+O+Z-Y-	-	-	-	-	The first chromosome has a non-functional promoter and no expression will occur. The second chromosome will not be able to express either LacZ or LacY as the two genes are mutated.
t	+X-2+O-d+1 - A+Z+0+d-1	-	-	+	-	The second chromosome has a non-functional promoter and no expression will occur. The first chromosome has a functional LacZ which is inducible.