Proteins are subatomic biomolecules. They're produced by cells, so it's logical to assume that they are much tinier than cells, and of course, much tinier than the organelles that produce them. In a remarkable achievement, scientists have now obtained the first-ever photographs of single proteins. Using a "holography electron microscope," researchers tested on a range of protein samples, all just a few nanometers in size. Hemoglobin, the protein that transports oxygen in red blood cells, and cytochrome c, the protein that transfers electrons within the body, were just two examples.

Source: arXiv ...