1. are not involved as coenzymes. but they are still essential in our diet, and they are involved in important processes such as vision, bone formation, protection from oxidation, and blood clotting.
2. is a vitamin that is used in reactions that transfer single-carbon units. the vitamin also reduce the risk of birth defects such as spina bifida and cleft lip. women of child-bearing age should consume the recommended amount of this vitamin.
3. is involved in the formation of hydroxyproline and hydroxylysine, which are important amino acids and part of the collagen that forms the connective tissues. lack of this vitamin causes scurvy, which can be prevented with citrus and other fruits.
4. is absorbed from some foods like carrots in the form of carotene. the vitamin accumulates in the rods and cones of the eyes and plays a role in vision.
5. the act as coenzymes in the body. they do not stay bonded to only one enzyme, but are used over and over again by different enzymes.