The book provides "BioNumbers"—standardized values for biological constants.

: A supplementary book by Ron Milo and Rob Phillips that focuses strictly on the data and "back-of-the-envelope" calculations.

Cells are complex, dynamic systems that consist of various organelles, membranes, and cytoskeletal structures. The cell membrane, also known as the plasma membrane, is a thin, semi-permeable lipid bilayer that surrounds the cell and regulates the exchange of materials with the external environment. The cytoskeleton, composed of microtubules, microfilaments, and intermediate filaments, provides mechanical support, shape, and stability to the cell.