Chapter 2 Vocabulary - The Chemistry of Life

atom

The basic unit of matter; smallest unit of an element

compound

A substance formed by the chemical combination of two or more elements in definite proportions

molecule

Created when atoms are joined by covalent bonds; smallest unit of most compounds (technically only covalent bonds, even though you will hear both)

adhesion

Attraction between molecules of different substances

solvent

Substance in which solute dissolves

base

A compound that produces hydroxide (OH^-) ions in a solution; also called alkaline; pH above 7

carbohydrate

Compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ratio of 1:2:1

nucleotide

Subunits of nucleic acids

nucleus

The center of the atom; composed of protons and neutrons; positive charge

ionic bond

Formed when one or more electrons are transferred from one atom to another

hydrogen bond

Attraction between hydrogen atom with partial pos. charge and one with partial neg. charge; weaker than ionic/covalent

mixture

Material composed of 2 or more elements or compounds  that are physically mixed together but not chemically combined

suspension

A mixture composed of water and nondissolved material

buffer

A weak acid or base that can react with a strong acid or base to prevent sharp, sudden changes in pH; play an important role in maintaining homeostasis in organisms

monosaccharide

Single sugar molecule

protein

Macromolecules; polymers of amino acids; made up of nitrogen, hydrogen, carbon, oxygen

electron

A negatively charged particle with 1/1840 the mass of a proton; in constant motion

ion

A positively or negatively charged atom

cohesion

Attraction between molecules of the same substance

solution

A mixture in which all components are evenly distributed

pH

Measurement system that indicates the concentration of H⁺ ions or OH^- ions in a solution (how many would form if substance was dissolved in water)

monomer

A single molecule that can chain; smaller units used in polymerization

lipid

A large and varied group of biological molecules typically not soluble in water; made mostly of carbon and hydrogen, little oxygen

amino acid

Subunit of protein; compounds with an amino group and carboxyl group, linked by peptide bonds

element

A pure substance that consists entirely of one type of atom

covalent bond

When moving electrons travel about the nuclei of both atoms and are shared

solute

Substance dissolved in a solution

acid

Any compound that forms H⁺ ions in a solution; pH below 7

polymer

Monomers joined together form this

nucleic acid

Macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus; polymers assembled from monomers called nucleotides

polar

Partial neg charge one side partial pos charge on other