1. A nitrogenous base: This is a ring-shaped molecule containing nitrogen. There are five main types of nitrogenous bases found in nucleic acids: adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U).

2. A five-carbon sugar: This sugar is either ribose (in RNA) or deoxyribose (in DNA).

3. A phosphate group: This is a group of one phosphorus atom and four oxygen atoms.

These three components come together to form a nucleotide.