It is the primary component of chromosomes. Enzymes are important in the construction and degradation of other molecules. It is polymerized to make cellulose and chitin. These may function in cell-cell recognition, such as in human blood groups and immune system response, as well as in resisting compression of cells. It binds oxgen molecules, and in chordates serves as the means by which the oxygen is supplied to the cells of the body.
Hydrophilic compounds dissolve easily in water, and are usually polar.
Hydrophobic compounds do not dissolve easily in water, and are usually non-polar. Oils and other long hydrocarbons are hydrophobic. They are among the largest molecules known. It contains a sugar, a phosphate group, and an organic base. ATP is a nucleotide.