Answer:
a. PPOs are denatured at high temperature
Explanation:
Polyphenol oxidase, PPO, is one of the most studied enzymes in the food industry as it is responsible for enzymatic browning reactions in fruits and vegetables. One of the reasons why its study is important is because commercially it is undesirable, since it modifies the sensory, nutritional and in general quality properties that impair the commercialization of a product.
The importance of controlling polyphenol oxidase is that it largely determines the quality and economic value of fruits and vegetables harvested, stored and processed. Bruising, chopping and other mechanical procedures damage the walls of fruits and vegetables which allows oxygen to penetrate, resulting in darkening or enzymatic browning reactions.
Enzymatic browning can be controlled through the use of chemical and physical methods, often used in combination. The commonly used physical methods are the reduction of temperature, oxygen and the use of modified atmospheres or coating films. The use of chemical methods will depend on what you want to inhibit, be it the enzyme, the substrate (oxygen or phenolic compounds) or the products.
Answer:
B. Corundum
Explanation:
Using the Mohs scale of hardness, the mineral has a hardness greater than 6.5 (Steel nail) but less than 8.5 (Drill bit). The corundum has a hardness of 9.0, which means it cannot be scratched by a drill bit, but all the other choices have a hardness scale less than 6.5 but the mineral was not scratched by the nail. So the best answer would be B.
Answer:
<em>Chargaff: </em>The work of Erwin Chargaff has major contributions towards understanding of DNA structure as a double helix. Although, he didn't propose the DNA as a double helix, but he was the first scientist two establish two rules that lead to the discovery of DNA as a double helix. Briefly, he proposed that (1) in any DNA, the amount of Guanine are always equal to the amount of Cytosine and likewise, the amount of Adenine are always equal to the amount of Thymine; and (2) the amount of guanine, cytosine, adenine and thymine bases are different in each species. This observation supported the idea later that DNA is the heriditary material rather than proteins.
<em>Franklin</em><em>:</em> Rosalind E. Franklin is known for her work on understanding the molecular structure of DNA via X-Ray diffraction. For that, she exposed crystallized DNA moleculeto X-rays and some of the rays were deflected back thus forming a diffraction pattern. She was the first scientist that produces real images of DNA explaining its molecular structure. As an example, I have attached the Photo 51 she took while working at King's College London. Her work led to the actual discovery of DNA as a double helix (Watson and Crick Model) which we know today.
<em>Watson and Crick</em>: James Watson and Francis Crick proposed the 3D structure and model of the DNA helix which we know as of today. Precisely, their work explained that DNA is a double-stranded, antiparallel, right-handed helix. Further, the nitrogenous basis proposed earlier (A, T, G, C) are attached to sugar-phosphate backbone via hydrogen bonds. It is one of the major discoveries in molecular biology.
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Answer:
D. They release waste into the bloodstream.
Explanation:
Kidneys are the primary organs of the excretory system. Their primary function is to remove the metabolic waste from the blood and release it out of the body in the form of urine. The nitrogenous waste, drugs, uric acid, and other metabolic waste products are removed from blood in kidneys.
Hence, kidneys do not release the waste into the bloodstream, rather release them out of the body and filter the blood.
