Nucleic acids are made up of long chains of repeating units called nucleotides. Each nucleotide consists of three components:

1. A sugar:

* In DNA, the sugar is deoxyribose.

* In RNA, the sugar is ribose.

2. A phosphate group: This is a negatively charged group that links the sugar molecules in the chain.

3. A nitrogenous base: These are the "letters" of the genetic code and come in five main types:

* Adenine (A)

* Guanine (G)

* Cytosine (C)

* Thymine (T) (found only in DNA)

* Uracil (U) (found only in RNA)

The sequence of these bases along the nucleic acid chain carries the genetic information.

In DNA, the two strands are held together by hydrogen bonds between the bases, with A always pairing with T and G always pairing with C. This complementary base pairing is crucial for DNA replication and protein synthesis.

In RNA, the single strand of nucleotides carries the genetic code from DNA to the ribosomes, where proteins are made.