Organic Molecules of Life Vocabulary

Flashcards covering the vocabulary from Chapter 3 of Essentials of Biology, Sixth Edition, focusing on organic molecules.

Organic Molecules

Molecules that contain carbon and hydrogen.

Inorganic Molecules

Molecules that do not contain a combination of carbon and hydrogen (e.g., H2O, NaCl).

Hydrocarbons

Chains of carbon atoms bonded only to hydrogen atoms.

Isomers

Molecules with the same number and kinds of atoms in a variety of arrangements, potentially having different properties.

Functional group

Specific combination of bonded atoms that always has the same chemical properties and reacts the same way.

Monomers

Subunits that join together to form polymers.

Polymer

Monomers joined together.

Dehydration synthesis reaction

Joins monomers to form polymers by removing a water molecule.

Hydrolysis Reaction

Breaks bonds in a polymer by adding a water molecule; OH group attaches to one monomer, and H attaches to the other monomer.

Carbohydrates

Mainly used for immediate energy source; may also be used for structural component.

Monosaccharides

Single sugar molecule; simple sugars with a 3 to 7 carbon backbone (e.g., glucose, fructose, galactose, ribose, deoxyribose).

Disaccharides

Two monosaccharides bonded together (e.g., maltose, sucrose).

Polysaccharides

Polymers of monosaccharides used for energy storage or structural components (e.g., starch, glycogen, cellulose, chitin).

Lipids

Insoluble in water due to long nonpolar hydrocarbon chains; used for long-term energy storage and waterproofing.

Unsaturated fats

Fatty acids with double bonds in the carbon chain, resulting in fewer hydrogen atoms.

Trans fat

An unsaturated fat where the C=C bond has H’s located on opposite side of bond.

Saturated fatty acids

Fatty acids with no double bonds between carbon atoms.

Phospholipids

Form the bulk of the plasma membrane; have a polar phosphate head (water-soluble) and nonpolar fatty acid tails (not water-soluble).

Steroids

Lipids made of four fused rings, derived from cholesterol; differ in functional groups.

Proteins

Composed of amino acid monomers; have many functions, including support, metabolism, transport, defense, regulation, and motion.

Peptide

Two or more amino acids covalently linked.

Peptide bond

Formed by dehydration reaction between two amino acid monomers.

Polypeptide

Chain of many amino acids joined by peptide bonds.

Denature

Loss of structure and function of a protein, usually due to pH or temperature changes.

Primary structure

Amino acid sequence of a protein.

Secondary structure

Portions of a protein chain that form helices or pleated sheets.

Tertiary structure

Overall three-dimensional shape of a protein, resulting from interacting secondary structures.

Quaternary structure

Structure of a protein with more than one polypeptide chain interacting.

Nucleic acids

Polymers of nucleotide monomers; include DNA (stores genetic information) and RNA (helps make proteins).

Nucleotide

Composed of a phosphate, 5-carbon sugar, and nitrogen-containing base.

DNA

Deoxyribonucleic acid; double helix with deoxyribose as sugar, uses thymine (T).

RNA

Ribonucleic acid; single-stranded with ribose as sugar, uses uracil (U) instead of thymine (T).