What are functional groups and what are their general purposes?

A: macromolecules made from joining smaller molecules called amino acids.

B: -The polar heads and fatty acid tails enable the cell to form a semi-permeable barrier between the inside of the cell and its environment.

C: is the proportion of a particular allele (variant of a gene) among all allele copies being considered

D: are molecules or parts of a molecule that can react with another molecule to affect the interactions of molecules.