Vitamin E and Alzheimer's Risk. A second study in the July issue of the Archives of Neurology shows that eating foods rich in vitamin E may help lower risks of developing dementia and Alzheimer's disease.
Ribose and Deoxyribose. The 5-carbon sugars ribose and deoxyribose are important components of nucleotides, and are found in RNA and DNA, respectively. The sugars found in nucleic acids are pentose sugars; a pentose sugar has five carbon atoms. A combination of a base and a sugar is called a nucleoside. Ribose, found in RNA, is a normal sugar, with one oxygen atom attached to each carbon atom. Deoxyribose, found in DNA, is a modified sugar, lacking one oxygen atom (hence the name deoxy).
The deoxyribose sugar of the DNA backbone has 5 carbons and 3 oxygens. The carbon atoms are numbered 1', 2', 3', 4', and 5' to distinguish from the numbering of the atoms of the purine and pyrmidine rings. The hydroxyl groups on the 5'- and 3'- carbons link to the phosphate groups to form the DNA backbone. Deoxyribose lacks an hydroxyl group at the 2'-position when compared to ribose, the sugar component of RNA. Nucleosides and Nucleotides. A nucleoside is one of the four DNA bases covalently attached to the C1' position of a sugar.