Question

Which of the following are all nucleotides?
A. Adenosine, Cytidylic acid, Cytosine
B. Adenylic acid, Cytidylic acid, Guanylic acid
C. Cytidine, Adenine, Adenylic acid
D. Uracil, Thymidine, Thymidilic acid

Answer 1

Nucleotides are the building blocks of nucleic acids such as DNA and RNA. The nucleic acids are made of long chains of nucleotides. A nucleotide is made up of sugar molecules, phosphate groups and a nitrogen-containing base. The sugar molecule is ribose in RNA or deoxyribose in DNA. The nitrogenous bases are adenine, guanine,cytosine and thymine. Uracil replaces the base thymine in RNA.

Complete answer:
Option A Adenosine, Cytidylic acid, Cytosine: Adenosine is a nucleoside made of adenine and a sugar molecule. Cytidylic acid is a nucleotide and Cytosine is a nitrogenous base.
Option A is incorrect.
Option B Adenylic acid, Cytidylic acid, Guanylic acid: Adenylic acid, Cytidylic acid and Guanylic acid are all nucleotides made of sugar, nitrogenous base and a phosphate group.
So, Option B is the correct answer.
Option C Cytidine, Adenine, Adenylic acid: Cytidine and Adenine are nucleosides and only adenylic acid is a nucleotide.
Option B is incorrect.
Option D Uracil, Thymidine, Thymidilic acid: Uracil is a nitrogenous base, Thymidine is a nucleoside and Thymidylic acid is a nucleotide.
Option D is incorrect.

Note:
Nucleosides are glycosylamines. They can be defined as nucleotides without a phosphate group. A nucleoside is made up of a simple nucleobase (or nitrogenous base) and a sugar molecule (ribose or deoxyribose). Whereas a nucleotide is made up of a nitrogenous base, a five-carbon sugar and one or more phosphate groups. The four nucleosides are Adenosine, cytidine, guanidine, thymidine or uridine.