Risk which is common to an entire class of assets or liabilities. The value of investments may decline over a given time period simply because of economic changes or other events that impact large portions of the market.
Properties of the alpha-helix. 1  The structure repeats itself every 5.4 Angstroms along the helix axis, ie we say that the alpha-helix has a pitch of 5.4 Angstroms. Alpha-helices have 3.6 amino acid residues per turn, ie a helix 36 amino acids long would form 10 turns.
When Watson and Crick produced their double helix model of DNA, it was known that most of the specialized features of the many different life forms on Earth are made possible by proteins. Structurally, proteins are long chains of amino acid subunits.