Short answer - While matcha and green tea both come from the same plant (Camellia sinensis), they are actually grown and prepared differently. You definitely can't simply grind some green tea leaves to powder and expect it to be the same thing as matcha. Although matcha contains whole ground leaves, it is even more nutritious and has more health benefits than standard green tea. Matcha is also with a richer, more full-bodied flavor.  In fact, matcha can contain up to ten times the nutritional value of standard green tea, and some sources say over 100x the antioxidant content. One of the most powerful types of antioxidants (catechin) - due to the way it's cultivated.