Humans are able to produce 20 different amino acids, which have side chains with differing properties. How does the variation in amino acids' side chains affect a cell? It allows for a wide variety of proteins to be produced that will carry out a wide variety of functions.
It causes the cell to produce a wider variety of proteins that all carry out the same function within the cell.
It requires the cell to acquire more energy to accommodate a wider variety of chemical bonds among side chains.
It results in individual proteins that can each carry out a wide variety of biochemical processes within the cell.