Question

E. coli is grown on medium containing a lac operon inducer and X-gal. What color will...

E. coli is grown on medium containing a lac operon inducer and X-gal. What color will the colonies be for each type? blue or white

Science   Biology   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

Ans) The colonies obtained will be Blue in color.

In the presence of inducer, the Lac Z gene will be transcribed and the Lac Z protein will be produced which then forms Beta-galactosidase. When X-gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranosidase) is present in the medium which is colorless is acted upon by the Beta-galactosidase and then the X-gal is hydrolyzed into blue colored product (5,5- Dibromo-4,4-dichloroindigo).This blue colored colonies are obtained when the plasmids are not cloned. Once the plasmids are cloned,then the insertion of DNA construct will disrupt the reading frame of lac Z gene and no lac protein will be produced and no blue colour will be produced.When the plasmids are transformed, white colonies are observed.

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
1. The lac operon responds to lactose and glucose. If wild-type E. coli cells are grown...
1. The lac operon responds to lactose and glucose. If wild-type E. coli cells are grown in media that contains both lactose and glucose, they will consume the glucose first because: (select all that apply) A.) the lac repressor remains bound to lacO, preventing the lac operon from being expressed at maximal levels B.) the permease (lacY) is not expressed in the presence of glucose, preventing lactose from entering the cell and being converted to allolactose, the inducer C.) the...
A mutant E. coli strain, grown under conditions that normally induce the lac operon, produces high...
A mutant E. coli strain, grown under conditions that normally induce the lac operon, produces high amounts of ß-galactosidase. What is a possible genotype of the cells? lacI– lacP+ lacO+ lacZ– lacY+ lacA+ lacI+ lacP– lacO+ lacZ+ lacY+ lacA+ lacI+ lacP+ lacO+ lacZ– lacY+ lacA+ lacI+ lacP+ lacOc lacZ+ lacY+ lacA ( if you are google searching for answer=the one in the quizlet is wrong)
The lac operon in E. coli regulates the co-expression of three genes needed for the degradation...
The lac operon in E. coli regulates the co-expression of three genes needed for the degradation of lactose (but absence of glucose) in the growth medium. These genes are not expressed when the bacteria has no lactose to feed on. How does the cell prevent expressing the lac operon in the absence of lactose? How does the presence of lactose activate the transcription of these three genes? (You do not need to explain the glucose level regulation.)
E. coli cells are growing in medium containing lactose but no glucose. Briefly describe the consequence...
E. coli cells are growing in medium containing lactose but no glucose. Briefly describe the consequence of the following changes (one to two sentences for each condition). a. Addition of high concentration of glucose. b. A mutation that inactivates galactoside permease. c. A mutation that inactivates beta-galactosidase. d. A mutation that affects binding of CAP to c-AMP e. A mutation that affects binding of inducer to LacI f. A lac operator mutation that deletes all of the O1
Which of the following accurately describes the status of lac operon regulation when E. coli cells...
Which of the following accurately describes the status of lac operon regulation when E. coli cells shift from using glucose to lactose as their carbon source? A. The lac repressor is active and the CAP protein is active, so the operon is transcribed B. The lac repressor is active and the CAP protein is inactive, so the operon is transcribed C. The lac repressor is inactive and the CAP protein is active, so the operon is transcribed D. The lac...
You isolated a mutant strain of E. coli in which the lac operon is constitutively expressed....
You isolated a mutant strain of E. coli in which the lac operon is constitutively expressed. To understand the nature of this defect, you created a partial diploid by introducing a plasmid containing a normal lacI gene (i.e. lacI+) and Z-. You then compared the mutant strain and the partial diploid with regard to their β-galactosidase activities in the presence and absence of lactose. You obtain the following results:                Lactose                        β-galactosidase expression Mutant                                     No                               High (constitutive expression) Mutant                                     Yes                             ...
An E. coli strain of chromosomal genotype lacI+ lacP- lacO+ lacZ+ lacY+. You wish to transform...
An E. coli strain of chromosomal genotype lacI+ lacP- lacO+ lacZ+ lacY+. You wish to transform this strain into a wild-type lac operon by the addition of an extra piece of DNA (plasmid). a. What gene or genes would you add on this extra DNA that would make this strain express the lac operon genes as wild type? ?b. How would you design thus plasmid if you want the strain of E. coli to express the lac operon genes even...
Which of the following are phenotypes that would result from Tn5 transposition into lacY on the...
Which of the following are phenotypes that would result from Tn5 transposition into lacY on the E. coli chromosome (the operon is constructed exactly like was shown in class) Survival of a galE deletion mutant on M9 minimal media plates supplemented with lactose and glucose Lac- White colonies when grown on LB+Xgal (Xgal is not transported by LacY, LacZ diffuses out of the cell) No measureable color change of media when cells are grown in media containing ONPG (ONPG is...
1.    The lac operon in E. coli comprises three structural genes, lac Z, lacY, and lacA....
1.    The lac operon in E. coli comprises three structural genes, lac Z, lacY, and lacA. It is regulated by both positive and negative mechanisms, involving binding of both a repressor protein and the catabolite activator protein (CAP). Transcription of the operon gives a polycistronic mRNA encoding the three enzymes. Under the following nutritional conditions, indicate whether or not the repressor and the CAP are bound by drawing them in on the appropriate regions of the operon. Indicate, as well,...
A theoretical operon (amo) in E. coli contains several structural genes encoding enzymes involved in the...
A theoretical operon (amo) in E. coli contains several structural genes encoding enzymes involved in the biosynthesis of a particular amino acid. Unlike the lac operon, in which the repressor gene is separate from the operon itself, for the amo operon, the repressor gene is found within the operon itself. When the end product amino acid is present, it binds to the repressor, and this complex binds to the operator, repressing the operon. In the absence of the amino acid,...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT