Why is it that all starch molecules are pretty much the same yet there are millions of kinds of protein molecules?

Answer 1

The basic building block of all starches is only glucose, this limits its variety. The basic building blocks of proteins are amino acids which have 20 different kinds which makes protein diverese. The structure of protein is another thing that makes it diverse, it have 4 different structures (primary, secondary, tertiary, and quaternary)

Answer 2

All starch molecules are NOT the same. Look at the wikipedia entry for starch: http://en.wikipedia.org/wiki/Starch - there you will find that there are many different forms of starch, largely dependent upon how many glucose molecules are in the chain or chains in the case of branched molecules of starch. The "sameness" of starch is from the basic building block of all starches, which is glucose.

Proteins on the other hand have amino acids as their building blocks. As such there will be more variations possible. See http://en.wikipedia.org/wiki/Protein - to read more.

The big difference between starch and protein is that starch is both an energy storage means, being made up of glucose which is used as a cell fuel, as well as a structural element, as in the fiber in plants. Protein on the other hand is not stored, per say in the body, but used for the many signaling molecules, insulin for example, as well as the wide variety of molecules used for digestion and other bodily processes, such as growing hair and nails.

Answer 3

Starch molecules are made up of many repeating units of glucose, leading to a relatively simple structure. In contrast, proteins are made up of a combination of 20 different amino acids, allowing for a much wider variety of sequences and structures. This diversity in amino acid composition and sequence leads to the vast number of unique protein molecules.

Answer 4

Starch molecules are arranged in a Semi-Crystalline manner. All the molecules of an element will be same. Starch becomes soluble in water when it is heated.