Change the display to sticks , to make the image easier to see. Drag the images, using the left mouse button, to give the 2 structures the same orientation, as above. In orienting the molecules, look for the ring O that bridges between C1 and C5, and the OH on C6, that sticks up out of the ring. An example is ribitol. Sugar acid - the aldehyde at C1, or the hydroxyl on the terminal carbon, is oxidized to a carboxylic acid.
Examples are gluconic acid and glucuronic acid.
Amino sugar - an amino group substitutes for one of the hydroxyls. An example is glucosamine. The amino group may be acetylated. For example, methanol reacts with a hydroxyl on glucose to form methyl glucoside . Maltose is the a anomer, because the O at C1 points down from the ring.