The monomer is the whole repeating unit
- The idea
- Predict
- See it
- Why
- Check
The idea
“Starch breaks into maltose, so that's its monomer. DNA is written in A, T, C and G, so bases are its monomers.”
Maltose is most of what amylase makes from starch, and A, T, C and G spell the genetic code. They feel like the building blocks.
The short version
The mistake: Starch breaks into maltose, so that's its monomer. DNA is written in A, T, C and G, so bases are its monomers.
What's actually true: A monomer is the whole unit that repeats. A functional group or a base is part of one, and maltose is two still joined.
- A monomer is the whole unit that repeats in a polymer. Dehydration synthesis joins monomers by removing water, and hydrolysis adds water to split them.
- Maltose and a dipeptide are only partly digested. Each still holds two monomers.
- An amino or hydroxyl group is a functional group on a monomer. A nitrogenous base is one of a nucleotide's three parts.
- Glucose builds starch, amino acids build proteins, and nucleotides build DNA and RNA.
On the exam: Break every bond between units. The whole piece that falls out is the monomer.