Wheat is a cereal plant (genus Triticum) that is the most important kind grown in temperate countries. The grain is ground to make flour for bread, pasta, pastry, etc. There are different kinds of wheat, such as durum wheat and winter wheat, and cultivated species such as emmer and einkorn. Please check those entries for more information or the Wikipedia link below.
Wheat germ is a tiny part of the wheat kerne about 2½%. The word germ refers to germination. It is very high in protein. It is also a concentrated source of several essential nutrients including Vitamin E, folate (folic acid), phosphorus, thiamin, zinc and magnesium, as well as essential fatty acids and fatty alcohols, and provides a good source of fibre. White bread has the wheat germ and the bran removed, rather pointlessly. Wheatgerm should be bought in small quantities as it goes rancid quite quickly.It should be stored in a fridge or freezer.