Nucleotides, Nucleosides & Bases — NEET Biology
✅ Asked in NEET 2025Living organisms have a number of carbon compounds in which heterocyclic rings can be found. Some of these are nitrogen bases – adenine, guanine, cytosine, uracil, and thymine. When found attached to a sugar, they are called nucleosides. If a phosphate group is also found esterified to the sugar they are called nucleotides. Adenosine, guanosine, thymidine, uridine and cytidine are nucleosides. Adenylic acid, thymidylic acid, guanylic acid, uridylic acid and cytidylic acid are nucleotides. Nucleic acids like DNA and RNA consist of nucleotides only. DNA and RNA function as genetic material.
NTA tests your ability to distinguish between nitrogen bases, nucleosides, and nucleotides—three related but different biomolecules. A nitrogen base (adenine, guanine, etc.) is just the ring structure. When a sugar (ribose or deoxyribose) attaches to the base, it becomes a nucleoside (e.g., adenosine). When a phosphate group also attaches to the sugar, it becomes a nucleotide (e.g., adenylic acid). Students commonly confuse these terms or mix up their definitions. Remember: Base + Sugar = Nucleoside; Base + Sugar + Phosphate = Nucleotide. DNA and RNA are polymers made only of nucleotides, not nucleosides or bases alone.
This paragraph was tested 2 times in NEET.
Match List-I with List-II: List-I A. Adenosine B. Adenylic acid C. Adenine D. Alanine List-II I. Nitrogen base II. Nucleotide III. Nucleoside IV. Amino acid Choose the option with all correct matches:
Which of the following is a nucleotide?
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.