Question

From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?

Answer 1

Enzymes are proteins. Protein molecules are macromolecules with highly complex structures. They are made up of amino acids. Around 300 types of amino acids are found in nature, but only 20 of these amino acids are found in animal and plant cells. Amino acids form chains and are linked to each other by peptide bonds. The sequence of amino acids in the polypeptide chain of each protein molecule is of a specific type. Proteins have very high molecular weight. Proteins made from different amino acids are of different types. Around 50,000 types of proteins are found in our body.

The biological macromolecules of DNA have a complex structure. These are biological macromolecules even larger than proteins (enzymes). Their molecular weight ranges from 10⁶ to 10⁹ Dalton. The DNA molecule is made up of a polynucleotide chain. m-RNA, t-RNA and r-RNA having molecular weight less than DNA are formed. RNA plays an important role in protein synthesis. For RNA synthesis, DNA molecule gets duplicated at different places and form small complementary chains, i.e. a small molecule of ribonucleotide acid. These are called primers. RNA: The synthesis of inserters is catalysed by the enzyme RNA polymerase. RNA molecules are used for protein synthesis. This makes it clear that DNA molecules are larger molecules than proteins (enzymes).