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
Answer:
Light energy, Water, and Carbon Dioxide/Chlorophyll
Explanation:
Photosynthesis uses 12 water molecules, 6 Carbin Dioxide molecules and light energy so it can produce one glucose, six water and oxygen molecules. This can be expressed and represented by 12H2O + 6CO2 + light energy = C6H12O6 + 6H2O + 6O2
Vital to remember that the produced oxygen is from the original water molecules and not the carbon dioxide.
Answer:
The answer is D- Dose-response relationship
Explanation:
A dose-response relationship is an association between dose and incidence in which an increasing level of exposure will either lead to an increase or decrease of an incident or outcome. For instance, in the scenario given the dose or exposure will be the time the infants are put to bed prone while the response is the level of incidence of SIDS (Sudden Infant Death Syndrome).
Answer:
What are stinkhorns? Stinkhorns are mushrooms that are found from the tropics to more temperate regions such as Wisconsin. They can suddenly appear in mulch, lawns, and areas with bare soil. These visually-shocking fungi get their common name from their characteristic, unpleasant odor. Although they are often unwanted additions to home gardens, stinkhorns do not cause plant disease. Because stinkhorns can grow on dead organic material, they actually are beneficial in that they contribute to the recycling of plant debris into nutrients that improve soil fertility and can be used by garden plants.
What do stinkhorns look like? Stinkhorns grow into various shapes, but they are bestknown for looking like horns or penises. A few species grow several appendages, resulting in an octopus-like appearance. Some species have a veil attached below the cap that resembles a lacey skirt flowing from the mushroom’s hollow stalk. Stinkhorns can range in color from white, beige, and olive to bright orange or red with black accents. The tips of mature stinkhorns are usually coated in a spore-containing slime. Gardeners often discover immature stinkhorns as they dig in the soil. The immature forms appear as whitish to pink or purple, egg-shaped masses. Stinkhorns develop rapidly sometimes growing up to four to six inches per hour, and can generate enough force to break through asphalt.
Where do stinkhorns come from? Stinkhorns are often first introduced into a garden in organic materials (e.g., soils and mulches) that contain microscopic hyphae (i.e., fungal threads) of stinkhorn fungi. Once stinkhorns mature, they produce a pungent, off-putting odor that is reminiscent of rotting flesh or dung. This smell may disgust people, but it attracts insects, particularly flies. Flies and other insects eat the slimy material at the tips of stinkhorns and carry spores in this slime to new locations as they move around in the environment. In many ways, this process is comparable to the distribution of pollen by bees (but of course without the more appealing scents associated with most flowers).
