AP Biology Topic 1.6: Nucleic Acids Vocabulary

Flashcards covering the vocabulary terms and key structural concepts of nucleic acids, DNA, and RNA from AP Biology Topic 1.6.

Nucleic Acids

Organic macromolecules made of long, unbranched strands of nucleotide monomers that store and convey genetic information based on their monomer sequences.

Nucleotide

The monomer unit of a nucleic acid, composed of a phosphate group, a five-carbon sugar, and a nitrogenous base.

Phosphate Group

A chemical component of a nucleotide containing one phosphorus atom bonded to four oxygen atoms.

Deoxyribose

The five-carbon sugar component found in DNA nucleotides, which contains one less oxygen atom than ribose.

Ribose

The five-carbon sugar component found in RNA nucleotides, which has a hydroxyl group attached to its two-prime ($2'$) carbon.

Nitrogenous Base

A nitrogen-containing component of a nucleotide; in DNA, it includes adenine ($A$), thymine ($T$), guanine ($G$), and cytosine ($C$).

DNA Backbone

The structural frame forming the sides of a DNA strand, composed of alternating phosphate groups and five-carbon sugars.

Antiparallel

The structural orientation of the two strands in a DNA molecule, running side-by-side in opposite directions ($5'$ to $3'$ and $3'$ to $5'$).

Double Helix

The three-dimensional, twisted-ladder shape characteristic of a two-stranded DNA molecule.

Base Pairing Rules

The principle stating that adenine ($A$) always bonds with thymine ($T$) (or uracil ($U$) in RNA), and cytosine ($C$) always bonds with guanine ($G$).

Hydrogen Bonds

The weak interactions that hold complementary nitrogenous base pairs together in the middle of a DNA molecule.

Uracil

The nitrogenous base ($U$) found in RNA that replaces thymine ($T$) and pairs with adenine ($A$).

$5'$ End

The terminal end of a nucleic acid strand where the five-prime carbon of the sugar molecule is attached to a phosphate group.

$3'$ End

The terminal end of a nucleic acid strand defined by the three-prime carbon of the sugar, to which new nucleotides are added during nucleic acid synthesis.