10 Jun BIOGD 2800 – An E. coli strain is Lac-negative
Question
An E. coli strain is Lac-negative because of a chromosomal deletion that removes the entire lac operon. When transformed with a plasmid vector carrying an antibiotic resistance gene and a 9.3 kb restriction fragment that contains the entire lac operon, the resulting transformant is able to grow on lactose. A spontaneous mutant was isolated from a culture of the transformant. The mutant was unable to grow on lactose, but was still antibiotic resistant. Plasmid DNA from this mutant was isolated. The restriction fragment containing the lac operon was found to be 10.5 kb in size.
a) Based on these results, what is the most probable cause of the mutation?
b) Further experiments reveal that the Lac-negative mutant (derived from the original transformant) reverts to Lac-positive phenotype at low frequency. Would you expect mutagens that cause either base-pair substitutions or single base-pair insertions and deletions to increase the frequency of Lac-positive revertants? Why?
Our website has a team of professional writers who can help you write any of your homework. They will write your papers from scratch. We also have a team of editors just to make sure all papers are of HIGH QUALITY & PLAGIARISM FREE. To make an Order you only need to click Ask A Question and we will direct you to our Order Page at WriteDemy. Then fill Our Order Form with all your assignment instructions. Select your deadline and pay for your paper. You will get it few hours before your set deadline.
Fill in all the assignment paper details that are required in the order form with the standard information being the page count, deadline, academic level and type of paper. It is advisable to have this information at hand so that you can quickly fill in the necessary information needed in the form for the essay writer to be immediately assigned to your writing project. Make payment for the custom essay order to enable us to assign a suitable writer to your order. Payments are made through Paypal on a secured billing page. Finally, sit back and relax.
About Writedemy
We are a professional paper writing website. If you have searched a question and bumped into our website just know you are in the right place to get help in your coursework. We offer HIGH QUALITY & PLAGIARISM FREE Papers.
How It Works
To make an Order you only need to click on “Order Now” and we will direct you to our Order Page. Fill Our Order Form with all your assignment instructions. Select your deadline and pay for your paper. You will get it few hours before your set deadline.
Are there Discounts?
All new clients are eligible for 20% off in their first Order. Our payment method is safe and secure.