7.3.4 DNA (Deoxyribonucleic Acid) and Other Naturally Occurring Polymers

DNA (deoxyribonucleic acid)The molecule carrying genetic instructions used in the growth, development, functioning, and reproduction of all living organisms. is a complex and crucial molecule found in all living organisms and viruses. It serves as the primary genetic materialDNA that carries the instructions for cell structure and function., encoding the instructions necessary for the development, functioning, and reproduction of organisms.

The structure of DNA consists of two long polymer chains, known as strands, which are coiled around each other to form a double helix. Each strand is composed of individual units called nucleotides. A nucleotideThe basic building block of DNA and RNA, consisting of a sugar, phosphate, and base (A, T, G, or C). consists of three components: a sugar molecule (deoxyribose), a phosphate group, and one of four nitrogenous bases (adenine, thymine, cytosine, or guanine). The two strands of DNA are held together by hydrogen bonds between the complementary base pairs: adenine (A) with thymine (T), and cytosine (C) with guanine (G).

Proteins are another type of naturally occurring polymer that plays essential roles in living organisms. They are composed of smaller units called amino acids. There are 20 different amino acids commonly found in proteins, and their specific sequence determines the structure and function of the protein.

Starch and cellulose are polysaccharides, which are complex carbohydrates composed of repeating sugar units. Both starch and cellulose are made up of glucose monomers, but they differ in their arrangement and bonding. Starch is a storage form of glucose in plants, while cellulose forms the structural component of plant cell walls.

Conclusion

DNA is a nucleic acid composed of nucleotide monomers, while proteins are composed of amino acid monomers. Starch and cellulose are polysaccharides made up of glucose monomers. These naturally occurring polymers, including DNA, proteins, starch, and cellulose, play fundamental roles in the functioning and organisation of living organisms.