A type of lipid with four carbon rings and no fatty acid tails.
Steroid
A molecule with three fatty acid tails that is entirely hydrophobic; main component of fats.
Triglyceride
Fatty acid with one or more carbon-carbon double bonds in its tail.
Unsaturated fatty acid
Water-repellent substance that is a complex varying mixture of lipids.
Wax
Substance that consists mainly of triglycerides
Fat
Small organic compound that is a subunit of proteins. Consists of a carboxyl group, an amine group, and a characteristic side group (R), all typically bonded to the same carbon atom.
Amino acid
To unravel the shape of a protein or other large biological molecule.
Denature
A bond between the amine group of one amino acid and the carboxyl group of another. Joins amino acids in proteins.
Peptide bond
Polymer of amino acids; an organic molecule that consists of one or more polypeptides.
Protein
Nucleiotide monomer of RNA; also serves an imoportant role as an energy carrier in cells.
ATP
Deoxyribonucleic acid. Nucleic acid that consists of two chains of nucleotides twisted into a double helix; holds heriditary information.
DNA
Chain of nucleotides; DNA or RNA.
Nucleic acid
A small molecule with a five-carbon sugar, a nitrogen-containing base, and one, two or three phosphate groups. Monomer of nucleic acids; some have additional roles.
Nucleotide
Infectious protein.
Prion
Nucleic acid that consists of a chain of nucleotides. Carries out protein synthesis.
RNA Ribonucleic acid
Theory that all organisms consist of one or more cells, which are the basic unit of life; all cells come from division of preexisting cells; and all cells pass DNA to offspring.
Cell Theory
Semifluid substance enclosed by a cell's plasma membrane.
Cytoplasm
Of a cell, an organelle with two membranes that holds the cell's DNA.
Nucleus
Structure that carries out a special metabolic function inside a cell.
Organelle
Membrane that encloses a cell and separates it from the external environment.
Plasma membrane
A relationship in which the volume of an object increases with the cube of the diameter, and the surface area increases with the square.
Surface-to-volume ratio
Plasma membrane protein that fastens cells together in animal tissues
Adhesion protein
Model of a cell membrane as a two-dimensional fluid of mixed composition
Fluid mosaic
Membrane protein that triggers a change in cell activity in response to a stimulus such as binding a certain substance.
Receptor protein
Protein that moves specific ions or molecules across a membrane.
Transport protein