BIOL 1220: Chapter 2 - Chemistry Key Terms

Cation

ion with a net positive charge, electron donor

Anion

ion with a net negative charge, electron acceptor

Organic compounds

Contain carbon, held together by covalent bonds, made by living things, e.g. proteins, fats, and carbohydrates.

Inorganic compounds

Do not contain carbon, e.g. water, salts, and many acids and bases.

Hydrolysis

Process in which water is used to split a substance into smaller parts.

Dehydration synthesis

Process by which a large molecule is synthesized by removing water and covalently bonding smaller molecules together.

Electrolytes

Ionize and dissociate in water and are capable of conducting an electrical current, e.g. salts, acids, and bases

Hydroxyl ion

Liberated when a hydroxide (a common inorganic base) is dissolved in water

Buffer

Minimizes or resists changes in pH by releasing or binding hydrogen ions.

Bicarbonate buffer system

carbonic acid dissociates reversibly, releasing bicarbonate ions and protons; carbonic acid and bicarbonate ion resists changes in blood pH by shifting to the right or left as H+ ions are added to or removed from the blood

Carbonic acid

weak acid in bicarbonate buffer system

Bicarbonate

weak base in bicarbonate buffer system

Polymer

chainlike molecules made of smaller, identical or similar subunits (monomers)

Carbohydrate

Organic compound composed of carbon, hydrogen, and oxygen; includes starches, sugars, cellulose; 1–2% of cell mass.

Monosaccharide

one sugar; building block of carbohydrates; e.g., glucose

Disaccharide

double sugar; e.g., sucrose, lactose

Polysaccharide

many sugars; a polymer of linked monosaccharides; e.g., starch, glycogen

Lipid

Hydrophobic organic compound formed of carbon, hydrogen, and oxygen; e.g. fats and cholesterol.

Triglyceride

Building block of lipids, composed of three fatty acids bonded to a glycerol molecule, store energy, insulate, and protect

Glycerol

sugar alcohol

Fatty acid

linear hydrocarbons

Saturated fatty acid

Fatty acid chains with only single covalent bonds between carbon atoms

Unsaturated fatty acid

Fatty acids that contain one or more double bonds between carbon atoms

Phospholipid

Modified lipid, two fatty acid chains, a phosphate group with an attached nitrogen-containing group, compose membranes, help transport lipids in blood

Steroid

flat lipids made of four interlocking hydrocarbon rings act as hormones and constituents of membranes

Cholesterol

Steroid found in animal fats as well as in most body tissues; made by the liver, starting molecule for synthesis of all body steroids, constituents of membranes

Protaglandins

eicosanoids derived from fatty acids in cell membranes, promote inflammation, stimulate uterine contractions, regulate blood pressure, contribute to clotting, and control GI tract motility.

Proteins

Organic compound that consists of one or more chains of amino acids e.g. enzymes, structural components; 10–30% of cell mass.

Amino acids

building blocks of proteins of which there are 20 common types

Denaturation

proteins unfold and lose their specific 3D shape when pH drops or temp rises and fragile hydrogens bonds break

Enzyme

Protein that acts as a biological catalyst to speed up a chemical reaction.

Substrate

Reactant on which an enzyme acts to cause a chemical action to proceed

Active site

Region on the surface of an enzyme where it binds and interacts chemically with other molecules of complementary shape and charge.

Nucleic acids

Organic molecules that includes DNA and RNA.

Deoxyribonucleic acid

Nucleic acid found in all living cells; it carries the organism’s genetic information.

Ribonucleic acid

Nucleic acid that contains ribose and the bases A, G, C, and U. Carries out DNA’s instructions for protein synthesis.

Nucleotides

Building block of nucleic acids; consists of a sugar, a nitrogen-containing base, and a phosphate group

Adenine

A nitrogen-containing base with two rings (a purine)in both RNA and DNA; also found in various free nucleotides of importance to the body, such as ATP

Guanine

A nitrogen-containing base with two rings (a purine) that is part of a nucleotide
in both RNA and DNA

Cytosine

A nitrogen-containing base with one ring (pyrimidine) that is part of a nucleotide in both RNA and DNA

Thymine

A nitrogen-containing base with a single ring (a pyrimidine) found in DNA

Uracil

A nitrogen-containing base with one ring (a pyrimidine) found in RNA

Adenine triphosphate

Organic molecule that stores and releases chemical energy for use in body cells. Also acts as a neurotransmitter.

Phosphorylation

chemical reaction in which a phosphate molecule is added to a molecule; for example, phosphorylation of ADP yields ATP