In The Gno

Recall that a single nucleotide monomer, the individual building blocks of genes, is basically made of a sugar, phosphate group, and nitrogenous base.  The monomer itself, as previously mentioned, is usually referred to by the same name as the base it contains.  This is why the linear sequences of genes are sometimes explained as strings of GAACACCTG or TAACGAATTCGCC or any other millions of possible combinations.  Genes may be several hundreds of nucleotides long or even up to several thousand.

Genes are what actually contain the chemical instructions that tell our body to make certain proteins.  When gene segments of DNA are “read” by RNA (ribonucleic acid), they are decoded in triplet.  This means that RNA reads nucleotides in segments of three.  When RNA “reads” a gene’s instructions, each triplet of nucleotides, called a codon, equates to a particular amino acid.  There are twenty possible amino acids that may be produced.

For instance, when RNA “reads” the codon “TTT” it will translate that into an amino acid called Phenylalanine.  Individuals who lack a necessary enzyme to properly metabolize phenylalanine are afflicted with a rare disorder called phenylketonuria (PKU).  PKU screening is now routinely performed at birth in all United States hospitals.  On the other hand, if RNA “reads” the codon “GAG“, it will translate that into an amino acid called Glutamic acid.  Glutamic acid is the origin of the unique flavor given to certain ethnic foods.  This flavor has recently been named “umami” (Japanese for “yummy”) and has formally been added to the other four traditional flavors:  Sweet, salty, bitter, and sour.  Glutamic acid is believed to play a role in cognitive functions such as learning and memory.  Further, it is a key molecule in the process of cellular respiration, the crucial metabolic process that converts what we eat into energy.

Amino acids are the building blocks of proteins.  So as RNA “reads” a gene, several strings of amino acids are produced.  The end result is called a polypeptide.  One or more polypeptides makes a protein.  Because amino acids are all chemically different, they give proteins unique sizes, shapes, and structures.  Some proteins are enzymes that help lower the amount of energy it takes to start a chemical reaction.  Some proteins are transporters of certain substances within our circulatory system (like hemoglobin that carries oxygen).  Some proteins are chemical messengers, or hormones.  There are many other types of proteins in our bodies, and all play a vital role in proper body function and survival.