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
The complete question is :
Charlie is investigating friction. She will use the same amount of force to push two wooden balls across two level surfaces. Then she will record her results in the table below.
Which prediction will most likely describe how friction will affect her findings?
Answer:
The distance for Trial 3 will be greater than the distance for Trial 4 because the difference in surface roughness will affect friction.
Explanation:
The frictional force depends greatly on the roughness of the body surfaces. It acts opposite to the direction of motion when two body surfaces have a relative motion between them.
In the context, equal mount of force is applied to push the wooden balls. So the net force which acts on the balls are :
F' = F - f
Here, F = the force applied
f = force of friction
And f = μ.N (N = reaction force)
Here μ is the coefficient of friction that depends on the surface roughness. The frictional force will be less when the surfaces are smooth. Thus for the trails 3 and trial 4, the distance for trail 3 would be greater than trail 4 as the surface is polished and would offer less friction.
DNA, RNA,Protein,Trait
The DNA is transcribed into the RNA during the process 'transcription'. Then, RNA is later translated into proteins during the process 'translation'. Then the protein is turned into traits.
Answer: 1, 2, 4 are accurate.
Explanation:
1. Joe is on a hill (on a trail) above the ocean. The beach and ocean are at similar altitudes. Therefore Joe is at a higher altitude than if he was at the beach.
2. Since Joe is on a hill, he has a higher altitude than at sea level. Air at a higher altitude has lower density because there is less air "ontop" of itself than at lower altitudes. As well, his hill is above the ocean, which means there is a lot of water, making the air more humid than where he is. Humidity also makes air denser.
4.The air pressure will decrease if Joe goes up to higher altitudes because there will be less air on top of itself.
The correct answer for this question would be option D. Since the Gulf Stream is a warm water current that flows away from the equator to northern Europe, the cause for this would be most likely the <span>warm climates in northern Europe. Hope this answers the question. Have a great day!</span>
