If you leave your seeds in the refrigerator too long you get to learn something. The seed first extends a small tendril. it then forms a thicker stem at the end. Both stem and tendril continue to grow in length. The thick stem then developes feeding roots while back at the nexus at the other end the shoot begins to develope.(see Picture) I am sure that all these parts have proper names but I hope the picture is worth the thousand words I didn't use.