Deoxyribonucleic Acid (DNA)
Deoxyribonucleic acid (DNA) is a nucleic acid polymer composed of monomers called nucleotides. The structure of DNA involves dehydration synthesis and it stores, copies, and transmits genetic information.
Deoxyribonucleic Acid Definition
DNA, which stands for deoxyribonucleic acid, is found in the nucleus of eukaryotic cells and in the cytoplasm of prokaryotic cells.
Deoxyribonucleic Acid Structure
A nucleotide consists of a pentose sugar (either deoxyribose or ribose), a nitrogenous base, and a phosphate group. The phosphate group is located at the 5' carbon and the hydroxyl group is at the 3' carbon.
Deoxyribonucleic Acid Model
Creating polymers of DNA involves dehydration synthesis, where DNA nucleotides can only be added to the 3' end (hydroxyl) through phosphodiester bonds, forming the "backbone."
DNA Example
The construction of DNA is always from the 5' to 3' end, and the two backbones are anti-parallel. The bases connect with hydrogen bonds.
DNA Nucleotides List and Function
DNA consists of two types of nitrogenous bases: purines (nine-membered double rings) which include adenine and guanine, and pyrimidines (six-membered rings) which include thymine and cytosine. The base pairs according to Chargaff's rule, with the same number of adenine and thymine, and the same number of guanine and cytosine. A pairs with T and G pairs with C, with A and T forming two hydrogen bonds and G and C forming three hydrogen bonds.
History and Discoveries
Rosalind Franklin's x-ray diffraction and crystallography revealed the twisted strands and bases in the center of DNA, while Watson and Crick came up with the final double helix model of DNA. It was found that DNA has a negative charge due to the phosphate group.
In conclusion, DNA (deoxyribonucleic acid) plays a crucial role in genetics and heredity. Its structure and function enable the storage and transmission of genetic information, making it a fundamental component of all living organisms.
