What are the key components of a DNA molecule?

The key components of a DNA molecule are deoxyribose sugar, phosphate groups, and nitrogenous bases.

DNA, or deoxyribonucleic acid, is a complex molecule that carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms. It is composed of three main components: deoxyribose sugar, phosphate groups, and nitrogenous bases.

Deoxyribose sugar is a five-carbon sugar molecule that forms the backbone of DNA. It is called 'deoxyribose' because it is a deoxygenated form of the sugar ribose. This sugar molecule is crucial in the formation of the DNA structure as it connects the phosphate group and the nitrogenous base.

Phosphate groups are another key component of DNA. They are composed of one phosphorus atom and four oxygen atoms, forming a strong, stable molecule. These groups link the deoxyribose sugars together, creating the 'backbone' of the DNA molecule. The phosphate groups are negatively charged, which makes the DNA molecule overall a negatively charged molecule.

The nitrogenous bases are the third key component of DNA. There are four types of nitrogenous bases in DNA: adenine (A), guanine (G), cytosine (C), and thymine (T). These bases pair up to form the 'rungs' of the DNA ladder, with adenine always pairing with thymine, and cytosine always pairing with guanine. This base pairing is due to hydrogen bonding and is crucial for the DNA's double helix structure.

In summary, the DNA molecule is composed of deoxyribose sugar, phosphate groups, and nitrogenous bases. These components come together to form the double helix structure of DNA, which is essential for its role in storing and transmitting genetic information.