Diet soft drinks that are sweetened with aspartame carry a warning label for phenylketonurics. Why?

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All right. Hi, everyone. So this, this question is asking us which of the following best describes the relationship between pheno Nuria or PKU and amino acid deficiency. So, very quickly, recall, first and foremost, that PKU describes a disorder in which the metabolism of phenylalanine is affected. So with this in mind, let's consider option A in the multiple choice, it reads that PKU leads to a deficiency of all amino acids. Now, as mentioned before, right, PKU is specifically going to cause problems with metabolizing pheno alanine in particular. Now, even though phenylalanine of course, is going to be affected and this is going to cause imbalances in other amino acids, it's not going to cause deficiencies in all nine essential amino acids. So option A would be incorrect from here. Option B reads that PKU results in an inability to metabolize the amino acid phenylalanine, potentially causing a deficiency in tyrosine. Now, according to what we've been talking about before, the first part of the sentence is definitely true, right. PKU is the inability to metabolize the amino acid phenylalanine. But what does that have to do with thyroxine? Well, recall it, PKU is specifically caused by a deficiency in the enzyme known as phenylalanine, which I initially spelled wrong. The enzyme in any case is phenylalanine hydroxylase and phenylalanine hydroxylase is specifically known to take phenylalanine as the starting material and convert it into tyrosine. So people with this disorder, people with PKU are also going to have low levels of tyrosine because that's the product of the deficient enzyme. So option B is correct but for the sake of completeness, let's talk about the other answer. Choices. Option C says that PKU causes the body to overproduce amino acids leading to toxicity. Now, this is definitely not true, right? Because PKU is characterized by a deficiency of certain amino acids like pheno alanine and tyrosine. It's not or rather they're not being overproduced, they're being under produced. So from there, we can talk about option D which reads that PKU is unrelated to amino acid metabolism and affects only carbohydrate digestion. This is definitely not true because PKU is a disorder involving the metabolism of phenylalanine, which is an amino acid, so not directly related to carbohydrates. Therefore, as discussed previously, our answer is going to be Option B in the multiple choice and there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful

Diet soft drinks that are sweetened with aspartame carry a warning label for phenylketonurics. Why?

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Key Concepts

Aspartame

Phenylketonuria (PKU)

Warning Labels