Question

A combination of a ribose molecule, a thymine and a sugar molecule will form a
A. Ribosome
B. Nucleotide
C. Nucleic acid
D. ATP
E. ADP

Answer 1

Hint: Thymine is a nitrogenous base found in DNA. And it is absent in RNA. Uracil is found in RNA instead of thymine.

Complete answer:
Before analysing the option lets know a little more about ribose molecule and thymine. Ribose is a simple sugar molecule made up of carbon and hydrogen and they are found in RNA and DNA. In DNA it is a deoxyribose molecule. Thymine is a nitrogenous base found in DNA.

Now let's analyse the options one by one.
Options A) Ribosomes are present inside the cell, that are minute particles consisting of RNA. The function of the ribosome is synthesis of protein. RNA, which is the building blocks of ribosomes, consist of the nitrogen base called uracil instead of thymine. So this is an incorrect option.
Option B) Nucleotides are the building blocks of nucleic acids DNA and RNA. It has three parts called the phosphate group, nitrogen base and the pentose sugar molecule. Here thymine is the nitrogen base and ribose molecule is pentose sugar present in the nucleotide. Hence this is the correct option.
Option C) The two types of Nucleic acids present in the cells are DNA(Deoxyribonucleic acid) and RNA(Ribonucleic acid). Nucleic acids are the reason behind inheriting characteristics of every living being. They carry information and control the process of protein synthesis. And the monomers of nucleic acids are Nucleotides. So nucleic acids are made up of millions of nucleotides linked together. So this is an incorrect option.
Option D) ATP is Adenosine triphosphate is a nucleotide which helps in intracellular energy transfer. It provides energy for so many processes like muscle contraction, chemical synthesis etc. It consists of the nitrogen base adenine, the sugar molecule ribose and three phosphate groups that are bound to ribose. As it contains the nitrogen base adenine this is an incorrect option.
Option E) ADP is Adenosine diphosphate is an organic compound which is important in energy transfer in living organisms. ADP plus one phosphorus group plus free energy gives ATP plus water. This consists of 2 phosphate groups and the sugar molecule ribose and nitrogen base adenine. As it contains nitrogen base adenine instead of thymine this is an incorrect option.

Hence, the correct answer is option (B)

Note: Here the monomer of nucleic acid is nucleotides. So basically both of them consist of the same thing as a base. But in the question it is mentioned about the presence of a single nitrogen base and ribose molecule. That’s why the answer is Nucleotide.