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BIO 202 Assignment
Question# 1: Write a note on composition of Proteins?
Proteins are organic molecules composed of Carbon, Hydrogen, Oxygen and Nitrogen. Proteins are organic compounds which are polymers of amino acids. Proteins are created by linking together amino acid into protein links called polypeptide chains. There are twenty amino acids which make up proteins. Each amino acid consist of central Carbon atom. The central carbon is bonded to an amine group (NH2), a carboxyl group (COOH), a hydrogen atom and an R group. There are twenty types of amino acids of which 12 synthesized by human body and other 8 must be ingested in the foods we eat. These 8 are referred to as the essential amino acids. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes and which usually results in proteins folding into a specific three-dimensional structure that determine its activity. A protein contains at least one long polypeptide.
Amino Group and Carboxyl Group
Amino acids have a basic structure of three components, an amino group made of –H2N, a carboxyl group _COOH and there last group is called the R group or variable group which is composed carbon, hydrogen an oxygen. The arrangement of the C,H and O in this group determines the name of the amino acid. Amino acid can be linked together when the amino group of one amino acid is bonded to the carboxyl group of a different amino acid. The COOH donates an OH group and the NH2 donates a H. The OH and H come together to form a water molecule, so this process is called dehydration synthesis – water is removed from the something new. The bond which holds the amino acids together is called a polypeptide.
Amino acids are building blocks of proteins. It has the structure as shown in figure:
R denotes Alky group.
R group is main includes carbon and hydrogen. Because of that carbon and hydrogen is the most abundant elements, respectively, in proteins.
Acidity and Basicity
Because of Nitrogen in amine group and Oxygen in carboxylic group amino acids are able behave as base (Lewis Base, Nucleophile) However Hydrogen tend to behave acidic. This condition makes an amino acid an acid.
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