Treating Cancer with Chemistry
Cancer treatment is a complex and challenging effort. Cancer cells grow without the usual controls that act on normal cells . One approach to treating cancer is to alter the structure of the DNA in order to slow down or stop the growth of the abnormal cells. Compounds that structurally resemble the normal building blocks of DNA have been shown to be very effective in stopping some forms of cancer from spreading throughout the body.
The Swiss biochemist Friedrich Miescher first discovered nitrogen-containing compounds in the nuclei of cells in 1869. The term nucleic acid was used to describe these molecules because of their discovery within the cell nucleus and because of the presence of phosphate groups and their relationship to phosphoric acid. A nucleic acid is a large biopolymer consisting of many nucleotides. The two primary nucleic acids which are found in cells are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA is the carrier of genetic information and is ultimately responsible for how cells produce proteins in order to carry out all the functions necessary for life. RNA is a related molecule that is involved in the mechanism by which the information stored in DNA is eventually converted into protein molecules.
The basic components of nucleic acids are nucleotides. A nucleotide is a molecule that contains a five-carbon sugar, a phosphate group, and a nitrogen containing base. The five-carbon sugar is either ribose, in the case of RNA, or deoxyribose, in the case of DNA. The only difference between the two molecules is the presence of a hydroxyl group attached to one member of the carbon ring in RNA. In DNA, that same carbon atom is attached only to a hydrogen atom (see Figure below ). Note that in drawing the structure of organic molecules, the single hydrogen atoms are not shown in the structure but are understood to be attached at each carbon point unless another molecule is shown.
The sugars ribose and deoxyribose are components of RNA and DNA respectively.
The nucleotides form the backbone of RNA and DNA. Each nucleotide consists of a base, a pentose (either ribose or deoxyribose) and phosphate groups. Three of the bases in RNA and DNA are identical (adenine, cytosine, and guanine). Thymine is found in DNA while uracil is found in RNA.
- The definition of a nucleic acid is given.
- The definition of a nucleotide and structures of the five nucleotides are provided.
Read the material at the link below and answer the following questions:
- What was Miescher studying in 1868-1869?
- What was interesting about the chemical composition of the material he isolated?
- What did he call it and why?
- What is a nucleic acid?
- What is a nucleotide?
- Which pentose is in DNA and which is in RNA?