Exchange Exchange is a marketplace in which shares, options and futures on stocks, bonds, commodities, and indexes are traded. Principal U.S. stock exchanges are: New York Stock Exchange (NYSE), American Stock Exchange (AMEX), and National Association of Securities Dealers Automatic Quotation System (Nasdaq).
From Wikipedia, the free encyclopedia. The DielsâAlder reaction is an organic chemical reaction (specifically, a [4+2] cycloaddition) between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system.n a normal demand DielsâAlder reaction, the dienophile has an electron-withdrawing group in conjugation with the alkene; in an inverse-demand scenario, the dienophile is conjugated with an electron-donating group.
Light and dark reactions in photosynthesis Photosynthesis is divided into two parts: 1. Light-dependent reactions (light reactions) 2. Light-independent reactions (dark reactions). Light reactions need light to produce organic energy molecules (ATP and NADPH). They are initiated by colored pigments, mainly green colored chlorophylls.