Biology · Biomolecules · NEET
No. A nucleoside has only two parts: a nitrogen base and a pentose sugar, joined by an N-glycosidic linkage. The moment a phosphate group is added, it becomes a nucleotide. So the phosphate is the one part that separates the two. This is exactly what NEET asks in match-type questions.
Yes, that is a correct way to remember it. Nucleotide minus phosphate equals nucleoside. NCERT says: when a base is attached to a sugar it is a nucleoside; if a phosphate is also esterified to the sugar it is a nucleotide. So they share the base + sugar core and differ only by the phosphate.
Adenosine is a nucleoside (adenine base + ribose sugar, no phosphate). If you add a phosphate you get adenylic acid (AMP), which is a nucleotide. NCERT names adenosine as the nucleoside and adenylic acid as the nucleotide. This exact pair came in NEET 2025.
A nitrogen base alone (like adenine or guanine) is just the base. When that base is attached to a sugar, it becomes a nucleoside (like adenosine). So the order builds up: nitrogen base to nucleoside (add sugar) to nucleotide (add phosphate). NEET often lists all three in one match question to check if you can tell them apart.
The nitrogen base joins the pentose sugar through an N-glycosidic linkage (at the 1' carbon) to form the nucleoside. The phosphate joins the sugar through a phosphoester linkage (at the 5' carbon) to form the nucleotide. Knowing both bond names helps in NEET bond-matching questions.
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.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
A nucleotide has three parts: a nitrogenous base, a pentose sugar (ribose in RNA, deoxyribose in DNA), and a phosphate group. A nucleoside has only the first two.
Nucleoside example: adenosine (adenine + ribose). Nucleotide example: adenylic acid, also called AMP (adenine + ribose + phosphate). This is the exact pair NCERT and NEET use.
NCERT states there are 5 types of nucleotides, matching the 5 nitrogen bases (adenine, guanine, cytosine, thymine, uracil). Nucleic acids DNA and RNA are polymers of these nucleotides.
DNA and RNA are polynucleotides, meaning they are long chains of nucleotides (each has a phosphate). The phosphate is needed to form the phosphodiester bonds that link the chain, so nucleotides, not nucleosides, are the building blocks.
