Tenth nanometer ions such as potassium and sodium generate our nerve impulses. Sugars, amino acids, hormones and DNA are about one nanometer in size. Membranes that separate one cell from another or one subcellular organelle from another are about five fold bigger.
Proteins can be tens of nanometers across.
The organism can do what it does, and cannot do what it does not, because of the presence, absence, concentration, location and interaction of these nano structures . Nanobiotechnology is the fusion of biotechnology with nanofabrication to benefit both fundamental research into complex biological processes and the technology of nanoscale devices. Researchers in this field are either fabricating nanoscale devices to probe the function of biomolecules, cells, tissues, etc., are using biological materials to assist in the assembly of structures, or are mimicking biology in the construction of man-made devices. Protein complexes as large as 10,000 cubic nanometers can be rendered nonfunctional by the change of a single atom. Living systems sense their surroundings and report that information to control systems for the appropriate response.