For the lac genotypes shown in the table below, predict whether the structural genes (Z) are constitutive (always produced), permanently repressed, or inducible in the presence/absence of lactose (+ normal wildtype and mutant). Genotype I+O+Z+ Lactose Present Constitutive Repressed Inducible I+O+Z+ I-O+Z+ L-O+Z+ I+O-Z+ I+O-Z+ I+O+Z- I+O+z- Absent Present Absent Present Absent Present Absent
Added by Alyssa O.
Step 1
I+O+Z+: This is the wild-type genotype, so it should be inducible. Show more…
Show all steps
Your feedback will help us improve your experience
Madhur L and 87 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
GENETICS, Thank You! For the lac operon in E. coli, I = lacI, the repressor gene, P = the lac promoter, O = the lac operator, Z = lacZ or the beta-galactosidase gene, Y = lacY, the permease gene. (+ = gene intact or functional; - = gene deleted or nonfunctional). Fill in the table below using a '+' to indicate the presence of the enzyme and '-' to indicate the absence of the enzyme. Although there is residual expression in the absence of lactose, please call this '-' since there is a thousand-fold increase in the presence of lactose. Genotype No Lactose Lactose Lac Z Lac Y Lac Z Lac Y I+P-O+Z+Y+ I+P+O+CZ+Y+ I+P+O+Z+Y- /F' I-P+O+Z-Y+ I-P+OcZ+Y+ /F' IsP+O+Z-Y- I+P+O+Z-Y+ /F' I-P+O+Z+Y-
Suman K.
Analyze the following genotypes of the Lac Operon in E. coli. In each case, determine whether Beta-galactosidase (enzyme that digests lactose) and permease (membrane channel that brings lactose into the cell) would be made in the presence or absence of lactose. Simply select 'YES' if the enzyme is made or 'NO' if it is not. (Refer to the Lac Operon diagram for the meaning of the letters in the genotypes. Remember a "plus" superscript indicates normal functioning part of operon or repressor gene, a "minus" indicates loss of function, "OC" means "operator-constitutive", and "IS" means "super-repressor")
Sri K.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD