A mutant E. coli strain is found that synthesizes B-galactosidase and permease but no B-galactoside-transacetylase in the presence of lactose (or allolactose). What mutation(s) can lead to this outcome? The lac operon is shown here as a guide. zones where proteins bind DNA: genes and regulatory sequences lac I promoter operator lac Z lac Y lac A Lac repressor proteins B-galactosidase permease B-galactoside-transacetylase Operator Lac I promoter Lac Y Lac A Lac Z
Added by Amanda A.
Close
Step 1
The mutant strain synthesizes galactosidase (LacZ) and permease (LacY), so the genes for these proteins must be functional. This means there are no mutations in the lacZ and lacY genes. Show more…
Show all steps
Your feedback will help us improve your experience
Adi S and 51 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
A strain of E. coli shows the following activities (+ indicating presence of activity; - indicating absence of activity) of beta-galactosidase and permease in the absence and presence of lactose in the growth medium: Lactose absent: beta-galactosidase (+) Permease (-) Lactose present: beta-galactosidase (+) Permease (-) The genotype (haploid) of this strain is: (a) lacI- lacP+ lacO+ lacZ+ lacY+ (b) lacI- lacP+ lacO+ lacZ+ lacY- (c) lacI+ lacP- lacO+ lacZ+ lacY+ (d) lacI+ lacP+ lacO+ lacZ- lacY-
Shaiju T.
A mutant strain of E. coli produces beta-galactosidase in the presence and in the absence of lactose. Where in the operon might the mutation in this strain occur and why? in the lacI gene, which leads to an inactive lac repressor in the promoter region of the operon, where the mutation leads to the failure of the RNA polymerase to bind to the promoter in the operator region, where the mutation leads to the failure of the operator to normally bind the repressor near the lacI gene, where the mutation leads to increased levels of lac repressor being made in the operator region, which leads to increased binding of the lac repressor to the operator
James K.
Under which of the following conditions would the lac operon produce the greatest amount of β-galactosidase? The least? Explain your reasoning. Lactose present? Yes Glucose present? No Condition 1: Yes Condition 2: Yes Condition 3: No A mutant strain of E. coli produces β-galactosidase in both the presence and absence of lactose. Where in the operon might the mutation in this strain be located? Examine Figure 16.7. What would be the effect of a drug that altered the structure of allolactose so that it is unable to bind to the regulator protein?
Rebecca C.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD