Aspartate is synthesized from oxaloacetate, an intermediate of the citric acid cycle. Alanine is synthesized from pyruvate, a product of glycolysis. For example, alanine and aspartate are derived from substances produced during cellular respiration. With the exception of tyrosine, nonessential amino acids are synthesized from products or intermediates of crucial metabolic pathways. These nonessential amino acids are alanine, arginine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, and tyrosine. Of the 20 amino acids, 11 can be produced naturally. While amino acids are necessary for life, not all of them can be produced naturally in the body. Polar Acidic Amino Acids (Negatively Charged)

His: Histidine Lys: Lysine Arg: Arginine.

Polar Basic Amino Acids (Positively Charged)

Tyr: Tyrosine Asn: Asparagine Gln: Glutamine.

Cys: Cysteine Ser: Serine Thr: Threonine.

Met: Methionine Trp: Tryptophan Phe: Phenylalanine Pro: Proline.

Ala: Alanine Gly: Glycine Ile: Isoleucine Leu: Leucine.

The nonpolar amino acids are hydrophobic, while the remaining groups are hydrophilic. Below is a listing of the 20 amino acids grouped by their 'R' group properties. These interactions play a major role in protein folding and give proteins their 3-D structure. Nonpolar amino acids are the opposite (hydrophobic) in that they avoid contact with liquid. Polar amino acids have 'R' groups that are hydrophilic, meaning that they seek contact with aqueous solutions. Amino acids can be polar, nonpolar, positively charged, or negatively charged.

These gene codes not only determine the order of amino acids in a protein, but they also determine a protein's structure and function.Īmino acids can be classified into four general groups based on the properties of the 'R' group in each amino acid.

The genetic code is the sequence of nucleotide bases in nucleic acids ( DNA and RNA) that code for amino acids. The amino acid sequence of a protein is determined by the information found in the cellular genetic code. The 'R' group varies among amino acids and determines the differences between these protein monomers. Generally, amino acids have the following structural properties:Īll amino acids have the alpha carbon bonded to a hydrogen atom, carboxyl group, and amino group. Basic Amino Acid Structure: alpha carbon, hydrogen atom, carboxyl group, amino group, 'R' group (side chain).

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