The Answer is B i just took the test. Enjoy, i also just looked it up on a quizlet. That's another website you can use if it comes up in the search for the question.
<span>Other mutagens act by chemically modifying the bases of DNA. For example, nitrous acid (HNO2) reacts with bases that contain amino groups. Adenine is oxidatively deaminated to hypoxanthine, cytosine to uracil, and guanine to xanthine. ... Uracil pairs with adenine rather than with guanine.</span><span>
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Answer: There's no way one species can become another through depuranization, which is a random change.
Explanation:
In cells, environmental (chemical or physical) and metabolic factors can cause DNA damage, which is the molecule that stores genetic material. In these cases, the damage done to the DNA is repaired.
<u>Many of these lesions cause a permanent structural damage to the DNA, which can alter the ability to be transcribed, or can cause mutated genes to be transcribed resulting in another protein.</u> Particularly, depurination is the hydrolytically cleavage of the β-N-glycosidic bond between the purines (adenosine or guanosine) and the carbon of the sugar group found in the DNA. This mutation results in the loss of the purine base and leads to the formation of apurinic site and results and severely disrupts the DNA structure. The most important causes of depurination is the presence of endogenous metabolites inside the cell as a result of various chemical reactions and due to the presence of mutagenic compounds. However, these apurinic sites <u>are usually repaired by portions of the base excision repair (BER) pathway</u>.
There's no way one species can become another through depuranization, which is a random change. Because it is highly unlikely that 5000 mutations are able to accumulate every day without being repaired, and that they are just the right mutations to have the same characteristics as a chimpanzee. <u>If the depurinations are not repaired, the cell will most likely either die or become cancerous.</u>
In the nephron, approximately 20 percent of the blood gets filtered under pressure through the walls of the glomerular capillaries and Bowman's capsule. The filtrate is composed of water, ions (sodium, potassium, chloride), glucose and small proteins (less than 30,000 daltons -- a dalton is a unit of molecular weight). The rate of filtration is approximately 125 ml/min or 45 gallons (180 liters) each day. Considering that you have 7 to 8 liters of blood in your body, this means that your entire blood volume gets filtered approximately 20 to 25 times each day! Also, the amount of any substance that gets filtered is the product of the concentration of that substance in the blood and the rate of filtration. So the higher the concentration, the greater the amount filtered or the greater the filtration rate, the more substance gets filtered.
This filtration process is much like the making of espresso or cappuccino. In a cappuccino machine, water is forced under pressure through a fine sieve containing ground coffee; the filtrate is the brewed coffee. The arrangement of the glomerular capillaries in series with the peritubular capillaries is important to maintain a constant pressure in the glomerular capillaries, and thus a constant rate of filtration, despite momentary fluctuations in blood pressure. Once the filtrate has entered the Bowman's capsule, it flows through the lumen of the nephron into the proximal tubule.
