The chicken, the egg and the molecules – What are chickens made of? (1980)

David Phillips

In his first lecture, David Phillips goes past ‘which came first, the chicken or the egg?’ and asks what they’re both made of.

Watch time: 01:00:12
David Phillips holding a beaker filled with smoke
Image credit: Royal Institution

Lecture 1 – What are chickens made of?

 From the 1980 Programme:

In order to get a reasonable understanding of how living things are constructed, we need to consider only the simpler properties of molecules. How big are they? What kinds of atoms are they made of? What shapes do they have? Do they carry electrical charges? Each individual protein molecule can then be thought of as a giant jig-saw puzzle in three dimensions in which the component parts fit together neatly to form a compact structure. Furthermore, the proteins themselves form part of another larger puzzle in which they fit with other molecules to carry out their various tasks.

Skin and bone are made in large part from collagen, a protein with quite a simple three-dimensional structure very similar to rope. We shall see how the chemical structure of collage (the sequence of the component amino-acid molecules that make up its long chain) leads to the formation of a helical structure – like a spiral staircase – and how this structure determines the properties of skin, tendon and bone. Keratin, the protein of hair and nails, forms a different kind of helix that can be stretched to make a structure like silk. 


Which came first, the chicken or the egg? This is one of the best known of all riddles without an answer but it is now giving place to a new riddle about the molecules from which chickens and eggs – and human beings – are made. These molecules are proteins and nucleic acids.

This series of six lectures, five presented by David Phillips and one with Max Perutz, showcases the complexity and importance of the proteins that make up so much of life. The lectures weave through the DNA helix, unravelling the mechanism that links DNA and protein production, and asking ‘which came first, the DNA or the protein?’