Complex sentence: While all protein molecules begin as simple unbranched chains of amino acids, once completed they assume highly specific three-dimensional shapes; that ultimate shape, known as tertiary structure, is the folded shape that possesses a minimum of free energy.
Split into simpler sentences: While all protein molecules begin as simple unbranched chains of amino acids, once completed they assume highly specific three-dimensional shapes. That ultimate shape, known as tertiary structure, is the folded shape that possesses a minimum of free energy.