Organic Molecules

Isomers

Molecules that have the same chemical formula but different structures

Protein

The key structural and functional molecule that does the work of the cell, providing structural support and catalyzing chemical reactions

Nucleic Acid

A polymer of nucleotides that encodes and transmits genetic information

Carbohydrate

An organic molecule containing C, H and O atoms that provides a source of energy for metabolism and that forms a starting point for the synthesis of other organic molecules

Lipid

A hydrocarbon molecule that is soluble in nonpolar solvents but not water; lipids store energy, act as signaling molecules, and are a component of cell membranes

Polymer

A complex molecule made up of repeated simpler units connected by covalent bonds

Amino Acid

An organic molecule containing a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain; the building blocks (monomers) of proteins (polymers)

Nucleotide

A constituent of nucleic acids, consisting of a 5-carbon sugar, a nitrogen-containing base, and one or more phosphate groups

Sugar

The simplest carbohydrate molecule; also called a saccharide

Functional Groups

A group of one or more atoms that has particular chemical properties of its own, regardless of what it is attached to

Enzyme

A protein that functions as a catalyst to accelerate the rate of a chemical reaction; critical in determining which chemical reactions take place in a cell

Alpha Carbon

The central carbon of each amino acid

Amino Group

NH2; a nitrogen atom bonded to two hydrogen atoms, covalently linked to the central carbon atom of an amino acid

Carboxyl Group

COOH; a carbon atom with a double bond to oxygen and a single bond to a hydroxyl group. Because the hydroxyl group readily ionizes, releasing a proton, this group confers an acidic characteristic to molecules

R Group/Side Chain

A chemical group attached to the central carbon atom of an amino acid, whose structure and composition determine the identity of the amino acid

Peptide Bond

A covalent bond that links the carbon atom in the carboxyl group of one amino acid to the nitrogen atom in the amino group of another amino acid

Saccharide

The simplest carbohydrate molecule; also called a sugar

Monosaccharide

A simple sugar

Polysaccharide

A polymer of simple sugars; provide long-term energy storage or structural support

Glycosidic Bond

A covalent bond that attaches one monosaccharide to another

Triacylglycerol

A lipid composed of a glycerol backbone and three fatty acids

Glycerol

A 3-carbon molecule with OH groups attached to each carbon

Fatty Acid

A long chain of reduced carbons (carbon atoms bonded to hydrogen atoms) attached to a carboxyl group

Saturated

Describes fatty acids that do not contain carbon-carbon double bonds; the maximum number of hydrogen atoms is attached to each carbon atom

Unsaturated

Describes fatty acids that contain carbon-carbon double bonds

Steroid

A type of lipid; the precursor molecule for cholesterol and some hormones

Phospholipid

A type of lipid and a major component of the cell membrane