Monomer of cellulose is

Cellulose is a natural polymer present in the plant cell walls. They have glucose $\left({\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\right)$ as its monomer, which forms the repeating unit. These repeating units joined together form the structure of cellulose. However, amino acid and isoprene are monomers of the polymers- protein and natural rubber respectively.