Polymers

[Weaza_cfc]

Polymers - only one when it contains 50 + monomous molecules in a long chain?

[THFCUK]

i have 2 books and in both of them it just says that a macromolecule is a giant molecule made from many repeating units, which is called polymers but it does not state any where that its 50+ eg glucose is repeated many times in starch

[JohnLIreland]

Previous answer was right for a macromolecule, which most polymers are, but polymers can exist as very short chains. One structural unit is a monomer - which all polymers are made of. Bond two together and you get a dimer, three would give you a trimer. After that, their generic terminology is a polymer.

So a polymer can be anything that has as few as 4 repeat units but can go into millions.

BTW, a polymer that has bonds across the chains it forms, such as a rubber, could be considered essentially as a single molecule as there could be no individual chains left unlinked. A polythene bag, on the other hand, would consist of millions of individual molecular chains all tangled together. So they can be one molecule - even though it would have started off as individual monomers that were then reacted together.