This is a bit of a trick question! While DNA is certainly found within the cell, it isn't typically separated from other molecules in a way that implies a distinct physical separation. Instead, DNA is associated with and interacts with other molecules that help it function.

Here are the three key biological molecules that associate with DNA and play crucial roles in its function:

1. Proteins: DNA is packaged and organized by proteins called histones, forming structures called nucleosomes. These help condense the long DNA molecule into a manageable form within the nucleus. Other proteins are involved in DNA replication, transcription, and repair.

2. RNA: DNA serves as a template for RNA synthesis. RNA is a single-stranded molecule that is involved in protein synthesis.

3. Lipids: While not directly associated with DNA itself, lipids make up the cell membrane that encloses the nucleus, providing a barrier that separates the nuclear contents from the cytoplasm.

It's important to remember that these molecules don't "separate" from DNA in the sense of distinct compartments. They are all intricately involved in the structure and function of DNA, working together to ensure the proper functioning of the cell.