Read the following statements carefully: Statement I: Cytosine is a pyrimidine nitrogenous base. Statement II: Cytidine is a nucleotide formed by linking cytosine to a pentose sugar. Statement III: Cytidylic acid is a nucleoside containing a phosphate group. Statement IV: Cysteine is a sulphur-containing amino acid. How many of the above statements are correct?

Step-by-step solution

Statement I is correct. Cytosine is a pyrimidine nitrogenous base found in nucleic acids. Statement II is incorrect. Cytidine is a nucleoside, not a nucleotide. A nucleoside is formed when a nitrogenous base is linked to a pentose sugar. Statement III is incorrect. Cytidylic acid is a nucleotide, not a nucleoside. It is formed when a phosphate group is esterified to the sugar of the nucleoside cytidine. Statement IV is correct. Cysteine is an amino acid that contains sulphur in its side chain. Therefore, exactly tw