Selenocysteine is a rare amino acid residue that is incorporated during protein synthesis (instead of during post-translational modifications as is the case with other rare residues). It is made from serine, but it looks like cysteine with a selenium atom in place of the sulfur atom. It is only found in a few known proteins including glutathione peroxidases. Selenocysteine has a lower pK_a and lower reduction potential than cysteine.

A polysaccharide of 150 monosaccharides must have 149 glycosidic bonds. The formation of one glycosidic linkage results in the removal of one water molecule. We can find the answer by determining the number of each atom in 150 glucose molecules and subtracting the atoms found in 149 water molecules.

The anomeric designation is alpha because the hydroxyl group attached to carbon 1—the carbon adjacent to the heterocyclic oxygen with the highest priority substituent—is trans to the  group attached to carbon 5.

The structure represents glucose because the hydroxyl groups attached to carbons 2, 3, and 4 are positioned trans, cis, and trans (respectively) with respect to the  attached to carbon 5.

The anomeric designation is beta because the hydroxyl group attached to carbon 1—the carbon adjacent to the heterocyclic oxygen with the highest priority substituent—is cis to the  group attached to carbon 5.

The structure represents glucose because the hydroxyl groups attached to carbons 2, 3, and 4 are positioned trans, cis, and trans (respectively) with respect to the  attached to carbon 5.

The anomeric designation is alpha because the hydroxyl group attached to carbon 2—the carbon adjacent to the heterocyclic oxygen with the highest priority substituent—is trans to the  group attached to carbon 5.

The structure represents fructose because the hydroxyl groups attached to carbons 2, 3, and 4 of the pentose ring are positioned trans, cis, and trans (respectively) with respect to the  attached to carbon 5 and there is a  group attached to carbon 2 along with the hydroxyl group.

The anomeric designation is beta because the hydroxyl group attached to carbon 2—the carbon adjacent to the heterocyclic oxygen with the highest priority substituent—is cis to the  group attached to carbon 5.

The structure represents fructose because the hydroxyl groups attached to carbons 2, 3, and 4 of the pentose ring are positioned trans, cis, and trans (respectively) with respect to the  attached to carbon 5 and there is a  group attached to carbon 2 along with the hydroxyl group.

The anomeric designation is alpha because the hydroxyl group attached to carbon 1—the carbon adjacent to the heterocyclic oxygen with the highest priority substituent—is trans to the  group attached to carbon 5.

The structure represents galactose because the hydroxyl groups attached to carbons 2, 3, and 4 are positioned trans, cis, and cis (respectively) with respect to the  attached to carbon 5.

The anomeric designation is beta because the hydroxyl group attached to carbon 1—the carbon adjacent to the heterocyclic oxygen with the highest priority substituent—is cis to the  group attached to carbon 5.

The structure represents galactose because the hydroxyl groups attached to carbons 2, 3, and 4 are positioned trans, cis, and cis (respectively) with respect to the  attached to carbon 5.

When converting a linear sugar to its ring form, a bond is formed between the oxygen attached to carbon 5 and the carbon at position 1. All hydroxyl groups that are not attached to the carbon in position 1 and are oriented to the right end up trans to the  attached to carbon 5, while those that are in the left position end up cis to the  attached to carbon 5.

If the hydroxyl group attached to carbon 1 ends up trans to the  attached to carbon 5, the ring structure is considered alpha. If the hydroxyl group attached to carbon 1 is cis to the  attached to carbon 5, the ring structure is considered beta.

The alpha ring structure of D-glucose bonds the carbon 1 hydroxyl group trans to the carbon 5  group. The hyroxyl groups on carbons 2, 3, and 4 will be trans, cis, and trans with respect to the .

When converting a linear sugar to its ring form, a bond is formed between the oxygen attached to carbon 5 and the carbon at position 1. All hydroxyl groups that are not attached to the carbon in position 1 and are oriented to the right end up trans to the  attached to carbon 5, while those that are in the left position end up cis to the  attached to carbon 5.

If the hydroxyl group attached to carbon 1 ends up trans to the  attached to carbon 5, the ring structure is considered alpha. If the hydroxyl group attached to carbon 1 is cis to the  attached to carbon 5, the ring structure is considered beta.

The alpha ring structure of D-galactose bonds the carbon 1 hydroxyl group trans to the carbon 5  group. The hyroxyl groups on carbons 2, 3, and 4 will be trans, cis, and cis with respect to the .