Question 3
Every nucleotide is built from which three components?
The right answer is the one marked above.
A nitrogenous base, a pentose sugar and a phosphate group. Three parts, in every nucleotide there is.
An amino group, a carboxyl group and an R group describes an amino acid, the building unit of protein. Keep the two apart: three parts and a phosphate means nucleotide; an amino group and a carboxyl group means amino acid.