Both DNA and RNA are made up of building blocks known as

Both DNA and RNA are made up of building blocks known as

A. amino acids B. nucleotides C. complementary base pairs D. genes

The Correct Answer and Explanation is :

The correct answer is B. nucleotides.

Both DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are composed of smaller units known as nucleotides. A nucleotide is the basic building block of both DNA and RNA, and it consists of three components:

1. A phosphate group: This is a molecule consisting of a phosphorus atom bonded to four oxygen atoms. The phosphate group forms the backbone of the nucleic acid structure.
2. A sugar molecule: In DNA, the sugar is deoxyribose, while in RNA, the sugar is ribose. The difference between these sugars is the presence (in RNA) or absence (in DNA) of an oxygen atom on the second carbon of the sugar ring.
3. A nitrogenous base: This is a nitrogen-containing molecule that can be one of five types: adenine (A), thymine (T), cytosine (C), guanine (G), or uracil (U). The bases form the genetic code in DNA and RNA. In DNA, the bases are adenine, thymine, cytosine, and guanine, while in RNA, uracil replaces thymine.

These nucleotides are connected by covalent bonds between the sugar of one nucleotide and the phosphate group of the next, forming a sugar-phosphate backbone. The nitrogenous bases of the nucleotides, which extend from the backbone, engage in specific pairing with complementary bases on the opposite strand of DNA or RNA. In DNA, adenine pairs with thymine, and guanine pairs with cytosine. In RNA, adenine pairs with uracil, and guanine pairs with cytosine.

In summary, the building blocks of DNA and RNA are nucleotides, which are essential for encoding genetic information, making them the fundamental unit of both genetic materials.