So this entire ch two oh group points in the same direction, so up as this hydroxyl group. And when they point in the same direction, that type of sugar is known as the beta anemer, because this carbon here, carbon number one, is known as the anomeric carbon. Now, on the other hand, if this nucleophile attacks from the other side, we're going to form the other animal known as the alpha animal, and this is known as alpha dlucopyrenose. Now, notice in this particular case, this hydroxyl group points in the opposite direction with respect to this entire group here, that points up. So this points down and this points up. Now, when we discussed the open chain form of sugar molecules, we said that it's the fissure projection that is used to basically describe the three dimensional arrangement of the atoms, the stereo chemistry of the atoms in that sugar molecule.