Nucleic Acids include DNA (deoxyribonucleic acid) and RNA (ribonuleic acid)

1. In most organisms, DNA is the source of genetic material.  These genes code for amino acid sequences that form polypeptide chains that conform to make proteins.  These proteins are molecular "hardware tools the DNA uses to direct the cells operations."
2. Genes direct the synthesis for mRNA (messengerRNA).  mRNA binds to ribozomes that match the sequence on the mRNA strand with the appropriate amino acids to "print out" proteins.

Nucleic acids are polymers composed of monomers called nucleotides.  A nucleotide is composed of three parts:  a phosphate functional group (PO₄), a pentose sugar, and a nitrogeneous base (organic molecule).

PO4

+

deoxyribose (pentose)

+either

pyrimidines or purines 6-member ring of C & N 6-member ring fused to a 5-member ring cytosine (C), thymine (T) they differ in functional groups attached to the ring adenine (A), guanine (G) hey differ in functional groups attached to the rings

A hydrogen bonds with T.  G hydrogen bonds with C.  Thus DNA is composed of 2 strands and is a double helix.  This predictability also allows for the precise copying of genetic data.

A - T (with 2 H bonds)

G - C (with 3 H bonds)

Ribonucleic Acid

PO4

+

ribose (pentose)

+either

pyrimidines or purines 6-member ring of C & N 6-member ring fused to a 5-member ring cytosine (C), uracil (U) they differ in functional groups attached to the ring adenine (A), guanine (G) they differ in functional groups attached to the rings

IMPORTANT!  THERE IS NO BASE-PAIRING WITH RNA BECAUSE IT IS DOES NOT BASE-PAIR.

Nucleotides joined by covalent bonds are called phosphdiester linkages (the outside bonds in DNA; the only bonds in RNA).  This produces a backbone (-sugar-phosphate-sugar-phosphate-).

The sequence of bases specifies the amino acid sequence which specifies the protein conformation and function in the cell.