Amino acids, proteins and DNA GapFill

Amino acids contain an NH₂ functional group and a  OHCOOHCHOBr functional group. In the 20 amino acids that make up proteins, these two groups are attached to the same carbon, labelled as the   gamma (γ)beta (β)delta (δ)alpha (α) carbon. As one group is an acid and the other is a base, a proton can be transferred within the molecule, which will then contain both a positive charge and a negative charge, but have no net charge. Such an entity is called a  zwitteriontwitterionambionneutrion.

Proteins are biological polymers composed of amino acids. The amino acids are linked by  esteramineazoamide linkages. The structure of a protein is vital to its function. There are three levels of protein structure: primary, secondary and   trilateraltertiarythirdternary. Two common types of secondary structure are α-helices and   γ-helicesδ-pleated sheetsβ-pleated sheetsβ-helices. 

Enzymes are an important class of protein, and catalyse chemical reactions in the body. They do this by binding reactant molecules called   superstratesdopantssubstratesbiotins in a groove called the active site. The geometry of this groove is very particular to each enzyme, and is usually compatible with only one type of reaction. Some enzymes even discriminate between reactant enantiomers, and are said to have  stereotypicalstereospecificstereoexclusivestereophonic active sites. Enzyme activity can be disrupted by drugs that closely mimic the structure of the normal reactant molecules and block the active sites. Such drugs are called  prohibitorsdisinhibitorsinhibitorsexhibitors.

Another biological polymer is DNA, which is responsible for storing genetic information. Its monomers are called   glycosidesnucleosidesdeuteridesnucleotides. In turn, each of these monomers consists of a base, a  3-deoxyribose2-deoxyribose3-oxyribose2-oxyribose sugar, and a  chloratesulfatephosphatecarbonate group. In the body, two strands of DNA form a double  ellipsoidarcsheethelix. The two strands are held together by  covalent bondinghydrogen bondingvan der Waals forcesfriction between bases. Adenine (A) bases pair with thymine (T) bases, and cytosine (C) bases pair with guanine (G) bases. In each pair, the bases are said to be  correlatedtwinnedreciprocalcomplementary.