The structure a cell cannot function without to make proteins is the ribosome.

Here's why:

* Ribosomes are the protein synthesis factories of the cell. They read the genetic code from messenger RNA (mRNA) and use it to assemble amino acids into proteins.

* Without ribosomes, a cell would be unable to translate the instructions encoded in DNA into functional proteins. These proteins are essential for virtually every cellular process, from structural support and enzyme activity to transport and signaling.

Let me know if you have any other questions!