Question

How do proteins differ from polypeptides?

Answer 1

See Below

Explanation:

I'll start with a sweater.
Imagine a really long piece of yarn
Imagine the yarn knitted into a sweater.
The Yarn is the polypeptide, the sweater is the protein.

Polypeptide is a long stretch of amino acids bonded together (polymerized) by what is called an AMIDE bond....also known as a PEPTIDE bond in biology.

When the peptide is made by the ribosome, it starts to fold up into alpha helices and beta sheets. Then its hydrophobic amino acids try to get away from water and condense to the center (called the Hydrophobic Effect) - and now you have this globular 3D structure, and this is the protein.

Polypeptide is the long Chain......protein is the folded up polypeptide in its 3D form.