1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Doss [256]
3 years ago
14

A DNA fragment is introduced into the lacZ gene of a plasmid, which also contains an ampicillin resistance gene. What is the app

earance of bacteria transformed with this plasmid if they are spread on plates containing ampicillin and Xgal?

Biology
1 answer:
zhenek [66]3 years ago
8 0

Answer: The bacteria transformed with this particular plasmid will form white colonies on the plates containing ampicillin and Xgal.

Explanation: The lacZ gene produces an enzyme called β-galactosidase which is responsible for the breakdown of lactose into glucose and galactose. The lacZ gene is one of the three genes (the other two being lacA and lacY) of the lac operon which is responsible for the transport and mechanism of lactose in E. coli and many other bacteria.

In recombinant DNA technology, when a plasmid is to be used to transform a host cell, such markers are used to help screen the transformed cells from the ones that have not taken up the plasmid. Xgal present in the plates is an artificial substrate which is hydrolyzed by

β-galactosidase into 5-bromo-4-chloro-indoxyl which will dimerize and oxidise into 5,5'-dibromo-4,4'dichloro-indigo. This is a blue pigment which will give blue color to the bacterial cells. Introducing a DNA fragment in this lacZ gene will make it non-functional so it will not be able to produce the enzyme.

Therefore, when a bacterial cell is transformed with a plasmid containing ampicillin resistance gene and a DNA fragment introduced in the lacZ gene and then grown on plates containing ampicillin and Xgal, white colored colonies will appear. The white colonies will show the bacterial cells that have successfully taken up the plasmid with the DNA fragment incorporated in the lacZ gene as this will render the gene non-functional and will not produce β-galactosidase which will breakdown Xgal to give blue colonies. Since the plates contain ampicillin, only the bacterial cells that have been successfully transformed with the plasmid ( the ones that have the DNA fragment and the ones without it) will grow as the ampicillin resistance will give them resistance against ampicillin in the plates. The bacterial cells that have not taken up the plasmid will not be resistant to ampicillin and will not form colonies on the plate.

This is called blue-white screening which is used to identify successfully transformed host cells. A picture of this is given in the attachment, taken from the following website:

https://www.mun.ca/biology/scarr/Blue_&_White_Colonies.html

You might be interested in
A 6-month-old girl is taken to emergency department in January suffering from profuse watery diarrhea and vomiting. She has had
kati45 [8]

My diagnosis in this case is that the 6-month-old girl suffered from the infection caused by the virus called rotavirus.

<h3>What is rotavirus?</h3>

A rotavirus belongs to the genus within the family of virus called Reoviridae. They are made up of a double capsid and a double-stranded RNA genome.

The symptoms of this virus include:

  • watery diarrhea,

  • nausea and vomiting,

  • low-grade fever.

Therefore, the correct diagnosis should be that the 6-month-old girl suffered from the infection caused by the virus called rotavirus.

Learn more about virus here:

brainly.com/question/17395741

#SPJ1

5 0
2 years ago
if gene therapy in the future would allow one to artificially alter the expression of muscle fibers for athletic success, which
Over [174]

Answer:

Fast-Twitch Fibers: baseball pitching

Slow-Twitch Fibers: long distance swimming, long distance running

8 0
2 years ago
Light and radio waves travel through a vacuum in a straight line at a speed of very nearly 3.00 x 10 8 m/s. How far is ligth yea
Verdich [7]

Malia split up the large container of salsa that she bought equally into 5 bowls to place around her house for the party. If each bowl contained 8.5 ounces of the salsa, which shows the correct equation and value of x, the total amount of salsa in the original container?

3 0
3 years ago
Kendra wishes to build a model of a carbohydrate molecule, ideally containing as many monomers as possible. Which set should she
deff fn [24]

Answer:

Polysaccharides

Explanation:

Polysaccharides are sets of carbohydrates formed by the union of hundreds and miles of carbohydrate molecules, the set having the largest possible number of monomers

4 0
3 years ago
Plants release oxygen gas to the atmosphere. True False
Sophie [7]
False it is does not have plants it can be release oxygen gas to the atmosphere
3 0
3 years ago
Other questions:
  • The main reason that eating salty foods makes a person thirsty is that additional fluid is needed to
    12·1 answer
  • What body parts help a tiger shark live in the ocean?
    11·1 answer
  • Los Angeles is a city on the west coast of the United States that is very close to the Pacific Ocean. Land temperatures in Los A
    11·2 answers
  • Which is used to measure the length of a bicycle trail? A. km B. kg C. kmi D. kL
    12·2 answers
  • Why is it important to eat enough protein?
    12·1 answer
  • How could you use iron filings to tell which of two bar magnets is stronger?
    10·2 answers
  • Homozygotes with two sickle-cell alleles are selected against because of mortality. However, heterozygotes for sickle-cell allel
    9·2 answers
  • Explain the concept of natural selection.
    10·1 answer
  • Which of the following best explains the importance of Earth’s crust to living organisms?
    14·2 answers
  • A molecule of messenger RNA (mRNA) has just been synthesized in the nucleus of a human cell.
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!