BIOL 443/543 LECTURE SLIDES 6 (Organic Molecules: Lipids)

Vocabulary practice flashcards covering lipid structure, functions, classes, and cellular components based on the lecture notes.

Small Organic Building Blocks

The four main classes of small organic molecules in the cell—sugars, fatty acids, amino acids, and nucleotides—that serve as precursors to larger cellular macromolecules.

Amphipathic Lipids

Lipids containing both hydrophilic and hydrophobic regions that construct cellular membranes, including diacylglycerols (such as phospholipids), sphingolipids, and sterols.

Phosphatidylcholine

The most common phospholipid in cell membranes, composed of two hydrophobic fatty acid tails and a hydrophilic head group containing glycerol, phosphate, and a polar group.

Triacylglycerols (TAGs)

Highly reduced, non-polar lipids formed by linking three fatty acids to glycerol via ester linkages; stored as energy reserves (fats and oils) in cytosolic droplets.

Pheromones

Volatile lipid molecules used by organisms for inter-organismal communication.

Glycerolipids

A main structural group of lipids created through dehydration synthesis, composed of a glycerol backbone covalently linked to 1, 2, or 3 fatty acid chains.

Glycerol

A $3\text{C}$ sugar alcohol containing hydroxyl groups ($\text{-OH}$) that form covalent bonds with the carboxylic acid group of fatty acids.

Fatty Acids

Hydrocarbon chains ranging from $4$ to $>24\text{C}$ in length (with $16\text{C}$ and $18\text{C}$ being most common) with a carboxylic acid group at one end.

Unsaturated Fatty Acid

A fatty acid containing one or more $\text{C=C}$ double bonds (monounsaturated or polyunsaturated), which introduces a kink or bent shape to the hydrocarbon chain.

Saturated Fatty Acid

A fatty acid whose hydrocarbon chain contains no double bonds, allowing full hydrogen saturation; commonly found in meat and dairy products.

Diacylglycerols

Lipids consisting of a glycerol backbone bound to two fatty acid chains, functioning as key membrane formers.

Sphingolipids

Amphipathic lipids formed by dehydration synthesis between serine and 1 or 2 fatty acids; they contain nitrogen in an amide group and are found in the plasma membrane, particularly in the myelin sheath of the nervous system.

Sphingosine

A lipid precursor molecule formed by combining the amino acid serine with one fatty acid.

Isoprenoids

Also known as terpenoids, a main structural lipid group where the hydrocarbon chain is formed from repeating units of isoprene rather than fatty acids.

Sterols

Steroid lipids that possess a hydroxyl group ($\text{-OH}$), making them slightly amphipathic so they can orient within the lipid bilayer.

Dolichol Phosphate

A polyisoprenoid lipid consisting of a long-chain polymer of isoprene, used to transport activated sugars during membrane-associated synthesis of glycoproteins and certain polysaccharides.