Basically, cells are made of atoms, but compared to atoms cells are gargantuan.
DNA is a cell's "memory" as you call it, or information. It's a complex molecule made out of Desoxyribo Nuclear Acids (DNA) bits, which are fairly small molecules in themselves, but DNA strands are comprised of a huge number of these bits. The largest molecules and the basic building blocks that make up your cells are Proteins, which are pretty gigantic as well. DNA is used to coordinate creation and folding of proteins to get the right shape with the right sites and such so the protein can do what it does (usually catalyze chemical reactions).
Cells are usually divided in compartments (lysosomes and ribosomes and all that other jaz) by walls of specific fat molecules, which hold a Hydrophobic (water repelling) end and hydrophylic (water loving) end. When these are surrounded by water, they will bunch up to keep their hydrophobic ends dry, so they will form Double Layered walls (keeping the water-hating hydrophobic ends inside the wall and the Hydrophylic ends forming the inner and outer faces of the wall). This is the basic principle of compartmentalization in cells, and how chemical processes like Digestion can be excluded from the rest of the cell.
