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).
It has an alternating chemical phosphate and sugar backbone, making the 'sides' of the ladder. (Deoxyribose is the name of the sugar found in the backbone of DNA.) In between the two sides of this sugar-phosphate backbone are four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G).he specific base pairing provides a way for DNA to make exact copies of itself. Each half of the original DNA still has a base attached to its sugar-phosphate backbone. A new strand of DNA is made by an enzyme called DNA polymerase. It reads the original strand and matches complementary bases to the original strand.