For instance, the cartoon version of DNA that is presented to even lower-year biology undergraduates is of linearized strands. But of course, it's really all spooled and tangled and crunched up into the nucleus of cells. Note that the cell they simulated is of a prokaryote (no nucleus, much simpler cellular processes than e.g. a mammal cell). About 1-2% of our genes make proteins, although the proportion is much larger in single-celled organisms (less redundancy in the genome, no splicing, etc.) So when you hear that e.g. genes turn on or off, this is not a switch. It's literally some sections of DNA being unwound, and large complexes of mutually interacting molecules probabilistically glomming on and off the DNA. The actual 3d layout of this DNA "ramen" matters to e.g. bring promoter regions of genes close to the actual genes they control.

So basically, we have a schematic-level understanding of cellular processes, but to see the actual 3D interactions in realtime would be extremely illuminating.