Nucleic Acids: DNA and RNA Structure and Function

Vocabulary terms and definitions covering the structure, bonding, and functional differences of nucleotides, DNA, and RNA.

Nucleotide

A monomer consisting of three main parts: a pentose sugar with $5$ carbon atoms, a nitrogenous base containing carbon and nitrogen, and a phosphate group.

Polynucleotide

A polymer made of a long chain of nucleotides joined together through condensation reactions.

Phosphodiester bond

A bond that links nucleotides together, formed when the phosphate group of one nucleotide reacts with the sugar of another, releasing one molecule of water.

Sugar-phosphate backbone

A continuous chain of sugars and phosphates formed when nucleotides join together, which protects the nitrogenous bases on the inside of the double helix.

Hydrolysis reaction

A chemical reaction in which water is added to break phosphodiester bonds, converting polynucleotides back into individual nucleotides.

Nucleic acid

Any molecule composed of one or more polynucleotide chains, such as single-stranded RNA or double-stranded DNA.

DNA (Deoxyribonucleic acid)

A nucleic acid arranged as a double helix of two polynucleotide strands, whose primary role is to store and pass on heritable genetic information that codes for proteins.

Deoxyribose

The five-carbon pentose sugar component found in DNA nucleotides.

Purines

Larger nitrogenous bases composed of $2$ carbon rings; specifically adenine and guanine.

Pyrimidines

Smaller nitrogenous bases composed of only $1$ carbon ring; specifically cytosine and thymine in DNA.

Complementary base pairing

The specific pairing rule where a purine base always pairs with a pyrimidine base (adenine with thymine via $2$ hydrogen bonds, and cytosine with guanine via $3$ hydrogen bonds) to maintain a constant distance between backbones.

Antiparallel

The structural arrangement where the two strands in a DNA molecule run in opposite directions, with one running top-to-bottom and the other bottom-to-top.

RNA (Ribonucleic acid)

A single-stranded nucleic acid containing ribose sugar that uses the genetic information from DNA to synthesize proteins.

Ribose

The five-carbon pentose sugar found in RNA nucleotides.

Uracil

The pyrimidine base found in RNA that replaces thymine.