In Regards To Metabolism And Nutrition Why Do You Suppose Isomers Exist Advantages Of Having

Can Adderall cause a Urine Test to show positive for methamphetamine?

Absolutely! The urinalysis tests for any and all amphetamines, and methamphetamine is just one derivative. Similarly, Adderall is a combination drug comprised of two amphetamine salts, dextroamphetamine and levoamphetamine. Any of the three WILL show positive for amphetamines on a urine/drug test.For how long is it detectable in urine?Adderall is usually detectable in urine for as little as 24 hours and as long as 4 days after you stop using the medication. If you have been taking Adderall over a lengthy period of time, it may be detectable for up to one week.On average, amphetamines are cleared from your system within 72 hours; however, this varies depending on your body's size, type, and physiological functions.--- UPDATE: YES, THEY CAN BE DIFFERENTIATED...I notice a couple of answers claiming that Adderall amphetamines would not show positive on a methamphetamine test. The CORRECT answer is YES IT WILL SHOW AS POSITIVE. At this point, a competent lab would proceed to using standardized differentiation tests to figure out the source of the methamphetamine. The laboratory may run up to 3 distinct tests to produce a complete amphetamine profile. Learn more about this process here: Methamphetamine Urine Toxicology: An In-depth ReviewA positive methamphetamine test could be caused by use of an OTC product, a prescription drug, or illicit use. The challenge for the laboratory is to differentiate between the d and the l isomer forms of methamphetamine. The clinician needs this critical information because without the d:l-isomer ratio, the clinician is unable to narrow down the potential sources of the methamphetamine. Sample Lab Reports:OTHER SOURCES:Baselt RC. Disposition of Toxic Drugs and Chemicals in Man. 8th ed. Foster City, CA: Biomedical Publications; 2008.Brunton L, Blumenthal D, Buxton I, Parker K. Goodman & Gilman’s Manual of Pharmacology and Therapeutics. New York, NY: The McGraw-Hill Companies, Inc.; 2008.Esposito FM, Crumpton S, Mitchell J, Flegel RR. Evaluation of the 20% D-methamphetamine requirement for determining illicit use of methamphetamine in urine. J Anal Toxicol. 2012;36(6):399-404.

Why are D sugars and L amino acids used by human body instead of their other isomers?

I found this answer online written by Míra Kašpar · Charles University in Prague“There are a couple of reasons for biological homochirality.One, our galaxy has a chiral spin and a magnetic orientation, which causes cosmic dust particles to polarize starlight as circularly polarized in one direction only. This circularly polarized light degrades D enantiomers of amino acids more than L enantiomers, and this effect is clear when analyzing the amino acids found on comets and meteors. This explains why, at least in the milky way, L enantiomers are preferred.Two, although gravity, electromagnetism, and the strong nuclear force are achiral, the weak nuclear force (radioactive decay) is chiral. During beta decay, the emitted electrons preferentially favor one kind of spin. That's right, the parity of the universe is not conserved in nuclear decay. These chiral electrons once again preferrentially degrade D amino acids vs. L amino acids.Thus due to the chirality of sunlight and the chirality of nuclear radiation, L amino acids are the more stable enantiomers and therefore are favored for abiogenesis.I found this explanation elsewhere. Original thread is here:http://forums.studentdoctor.net/threads/why-are-only-l-amino-acids-found-in-nature.854644/“

What happened to L-sugar (left-handed sugar)? Are there any health issues with it? Why can't I buy it at my local grocery store?

Because it's expensive. Your logic is perfect: L-glucose tastes just like glucose and it's biologically useless. But, we have not developed industrial processes to produce it with commercially feasible costs. Probably the only way would be some kind of biosynthesis using custom enzymes, but it's highly complicated and would require some badass genetic manipulation, since the molecule is not used for anything and there are no enzymes which work with anything even close to L-glucose.On some side notes that you might be interested in, it might be said that old concepts about chirality are slowly being broken. A good example is D-serine: our body was thought to only use only L- enantiomer amino acids for biosynthesis. Some bacteria, however, produce D-serine for their cell walls as a clever trick, as many of our immune receptors won't work well with the opposite optical enantiomers.It has been found, however that our body does produce D-aspartic acid (even though it is not incorporated in proteins). Subsequently, it was discovered that D-serine is used in brain signaling, binding to the NMDA-receptors.About the sugars, look at this link:A NATURAL WAY TO STAY SWEETAbout D-serine in our brain:d-Serine is an endogenous ligand for the glycine site of the N-methyl-d-aspartate receptorThis has led to novel p applications for D-cycloserine, an atypical antibiotic most used in India:Biology of Mood & Anxiety Disorders(if this answer was helpful, please upvote it)

What is the most common glucose type found in human body; alpha or beta?

There is a critical distinction that is important to make in your question - Are you referring to glucose alone, or glucose monomers that are part of longer polysaccharides?If you want to know about glucose monomers in polysaccharides, they are mostly found in the alpha conformation. Animals don’t have enzymes that can break down poly-beta-glucose (also known as cellulose), which is found in high abundance in plants. In dietary terms, we call poly-beta-glucose “fiber” as those molecules will simply pass through our digestive tract. As such, when we build up our own polysaccharides, we always incorporate glucose in the alpha conformation.However, if we’re speaking about glucose monomers on their own, the story is completely different. Under normal conditions, glucose can break its ring structure to form a linear molecule. When the glucose re-forms a cyclical structure, it can be either the beta or the alpha conformation. This means that every molecule gets to freely sample all three conformations (linear, alpha and beta), and the three conformations will be in equilibrium.As we know from basic thermodynamics, at equilibrium the proportions of these three species will depend on the difference in free energy. Although it is not obvious how the energy of the linear form compares with the ring forms, we can easily use our chemical intuition to draw conclusions about which ring form is more stable.Glucose rings have six atoms in them, meaning that they will roughly adopt the typical chair-conformation that is found in hexane. The difference between the alpha and beta forms is in the position of the hydroxyl group that is attached to carbon #1. In the beta form the hydroxyl group is in the equatorial position with a hydrogen in the axial position. In the alpha form the hydroxyl group is in the axial position with a hydrogen in the equatorial position.As a general rule, it is more energetically favorable to put the larger groups in the equatorial position. Therefore, we would expect that beta-glucose is more stable than alpha-glucose, and that more of the molecules adopt that conformation.

Why are trans-fats so bad for you?

In simple words, trans-fats are bad for the human body because they are difficult to metabolize due to their higher melting point and better stability, which is due to their linear and symmetrical structure. So they tend to be remain as solid for long and hence are associated with many cardio vascular diseases.Now onto a detailed explanation, cis and trans are terms used in organic chemistry to denote the structure of different isomeric organic molecules(geometric/configurational/cis-trans isomerism).The prefix “cis” indicates that the functional groups are on the same side of the carbon chain, while the prefix “trans” indicates that the functional groups are on the opposing sides of the carbon chain. Hence trans isomers are more stable than cis isomers, due to the symmetry in their structure, and will have a higher melting point and lower chemical reactivity.While it comes to fats, which mainly consists of carbon and hydrogen molecules and some functional groups like -COOH (carboxyl group), the same rules apply for “cis” and “trans” isomers.Hence trans fats, being more stable and less reactive, remain as solid itself in our body without undergoing metabolic reactions and lead to fat depositions in our arteries leading to cardio vascular diseases, by increasing the LDL (low-density lipoprotein cholesterol, also called "bad" cholesterol) levels and decreasing the HDL (high-density lipoprotein cholesterol, also called "good" cholesterol) levels.Examples of foods that contains trans fats:Doughnuts, cookies, crackers, muffins, pies, cakes etc.

What is the difference between glutamine and L-glutamine?

Glutamine comes in two flavors: D–glutamine, and L–glutamine.(L–gluatmine on left, D–glutamine on right)They differ by the arrangement of atoms around their alpha-carbon in their amino acid backbone. If you look closely, L-glutamine and D-glutamine are actually mirror images or enantiomers of eachother. In nature, the L form of glutamine (and amino acids in general) are the predominant form found in proteins made by the ribosome (and therefore are the vast majority of what we eat). In rare cases, D amino acids are found in posttranslational modification, cell walls, and some potential neurotransmitters. D–glutamine also isn't metabolized by the body; the form usable is L–glutamine.