Why are structurally complex molecules, such as most enzymes, composed of protein?

Question

Any ideas pls??

Answer 1

Proteins are the "effector" molecules, able to carry out complex tasks, while the DNA serves as the genetic template.

This is primarily because the 20 different types of amino acids can be put together in a huge number of different ways (leading to a vast array of different structure/functions), and some amino acids have different chemical properties, including positive charge (Arginine, Histidine and Lysine), negative charge (Aspartic acid and Glutamic acid), hydrophobic and hydrophilic; but there are a limited number of ways in which only 4 nucleotide bases can be put together.

Answer 2

Biologically speaking, things like starch, fat etc.. tend to be chemical chains composed of repeating patterns of stuff (polymers-- chains of carbohydrates for example).

Proteins are made up (normally) of folded chains of amino acids. There are lots of amino acids and they all have different properties. When amino acids are put together in groups, they affect each other. In the complex molecule hemoglobin, for example, a vast number of these amino acid building blocks enable the molecule to somehow loosely hold on to oxygen.

In short, the structural complexity related to proteins relates to the way that they are built (via chains of very different amino acids) and the way that each of these amino acids interact with each other and the environment. The way they interact with each other causes the molecule to bend, fold etc and take on many different and complex functions.

Inorganic enzymes (catalysts) seem to always be somewhat simple; composed of a single metal element for example.

Proteins on the other hand make up the highly complex molecules that are necessary for building vastly complicated living cells.