Drinking Age essays

Drinking Age essays In the year 2002, drinking has come to be a nation wide problem. Within the last few decades, all the states have changed the legal drinking age from 18 to 21. However, this prohibition of alcohol until the age of 21 has not been all that effective. From surveys it is easy to see that a dramatic percent of 18 year olds drink regularly even though they are not of legal age. In fact, underage drinking has never seemed to be as much of a problem as it is today. To many teens, the idea of alcohol being a forbidden fruit makes it all the more tempting to consume. Also, it is unfair to put adult responsibilities on 18 year olds, yet not allow them the responsibility to drink. Therefore, the drinking age should be lowered from 21 to 18 in the U.S. First, one of the main reasons that underage drinking takes place deals with the fact that alcohol is viewed by teens as a forbidden fruit. It is human nature to rebel against society. For example, when I was young, my parents used to always tell me not to play in the street. Yet whenever they were not looking, the first thing I always did was go and play in the street. This is what it is like when many teens are told they are not allowed to drink by the law, and their parents. It is almost as if the country refuses to remember the complete failure of both prohibition acts. Does the cliche, those who dont remember the past are condemned to repeat it, mean anything to the government? In fact, making 21 the legal drinking is a prohibition act in itself. Recent studies have shown that amongst all drinkers, 32% of under age drinkers are considered to be heavy drinkers, while only 24% of legal drinkers are considered heavy drinkers. In addition, many students in college are unde r the age of 21. Yet this is the place where flaunting of law breaking is so common. Considering this, it is senseless to uphold a law that cannot be enforced. ...

Amino Acid Definition and Examples

Amino Acid Definition and Examples Amino acids are important in biology, biochemistry, and medicine. Learn about the chemical composition of the amino acids, their functions, abbreviations, and properties: Key Takeaways: Amino Acids An amino acid is an organic compound characterized by having a carboxyl group, amino group, and side chain attached to a central carbon atom.Amino acids are used as precursors for other molecules in the body. Linking amino acids forms polypeptides. Polypeptides may be modified and combined to form proteins.The genetic code is basically a code for proteins made within cells. DNA is translated into RNA. Three bases (combinations of adenine, uracil, guanine, and cytosine) code for an amino acid. There is more than one code for most amino acids.Amino acids are made in the ribosomes of eukaryotic cells.Some amino acids may not be made by an organism. These essential amino acids must be present in the organisms diet.In addition to making amino acids from the genetic code and obtaining them from the diet, other metabolic processes convert molecules into amino acids. Amino Acid Definition An amino acid is a type of organic acid that contains a carboxyl  functional group (-COOH) and an amine functional group (-NH2) as well as a side chain (designated as R) that is specific to the individual amino acid. Amino acids are considered to be the building blocks of polypeptides and proteins. The elements found in all amino acids are carbon, hydrogen, oxygen, and nitrogen. Amino acids may contain other elements on their side chains. Shorthand notation for amino acids may be either a three-letter abbreviation or a single letter. For example, valine may be indicated by V or val; histidine is H or his. Amino acids may function on their own, but more commonly act as monomers to form larger molecules. Linking a few amino acids forms peptides. A chain of many amino acids is called a polypeptide. Polypeptides may become proteins. The process of producing proteins based on an RNA template is called translation. Translation occurs in ribosomes of cells. There are 22 amino acids involved in protein production. These amino acids are considered to be proteinogenic. In addition to the proteinogenic amino acids, there are some amino acids that are not found in any protein. An example is the neurotransmitter gamma-aminobutyric acid. Typically, nonproteinogenic amino acids function in amino acid metabolism. The translation of the genetic code involves 20 amino acids, which are called canonical amino acids or standard amino acids. For each amino acid, a series of three mRNA residues acts as a codon during translation (the genetic code). The other two amino acids found in proteins are pyrrolysine and selenocysteine. These two amino acids are specially coded, usually by an mRNA codon that otherwise functions as a stop codon. Common Misspellings: ammino acid Examples: lysine, glycine, tryptophan Functions of Amino Acids Because they are used to build proteins, most of the human body consists of amino acids. Their abundance is second only to water. Amino acids are used to build a variety of molecules and are used in neurotransmitter and lipid transport. Amino Acid Chirality Amino acids are capable of chirality, where the functional groups may be on either side of a C-C bond. In the natural world, most amino acids are the L-isomers. There are a few instances of D-isomers. An example is the polypeptide gramicidin, which consists of a mixture of D- and L-isomers. One and Three Letter Abbreviations The amino acids most commonly memorized and encountered in biochemistry are: Glycine, Gly, GValine, Val, VLeucine, Leu, LIsoeucine, Leu, LProline, Pro, PThreonine, Thr, TCysteine, Cys, C  Methionine, Met, MPhenylalanine, Phe, FTyrosine, Tyr, Y  Tryptophan, Trp, W  Arginine, Arg, RAspartate, Asp, DGlutamate, Glu, EAparagine, Asn, NGlutamine, Gln, QAparagine, Asn, N Properties of the Amino Acids The characteristics of the amino acids depend on the composition of their R side chain. Using the single-letter abbreviations: Polar or Hydrophilic: N, Q, S, T, K, R, H, D, ENon-Polar or Hydrophobic: A, V, L, I, P, Y, F, M, CContain Sulfur: C, MHydrogen Bonding: C, W, N, Q, S, T, Y, K, R, H, D, EIonizable: D, E, H, C, Y, K, RCyclic: PAromatic: F, W, Y (H also, but doesnt display much UV absorption)Aliphatic: G, A, V, L, I, PForms a Disulfide Bond: CAcidic (Positively Charged at Neutral pH): D, EBasic (Negatively Charged at Neutral pH): K, R