Grapes have been around for thousands of years. As grapes ripen on their vines, they turn:
translucent green
black
purple
red
Some types of grapes have edible seeds. Other types are seedless. Seedless grapes may be easier to eat, but grapes with seeds tend to be sweeter. The seed itself taste slightly bitter.

The grapes you find in your local grocery store are known as table grapes. Wine grapes are used to make wine. They are smaller than table grapes but have thicker skins and larger seeds.