Science Unit 2

Element

Chemical substance made up of one type of atom

Compound

Form when 2 or more different elements join

Ionic bond

A chemical bond based on transfer of electrons

Ion

A positively or negatively charged atom or molecule

Covalent bond

Bond between atoms based on shared electron pairs

Molecule

Form when 2 or more atoms join

Hydrogen bond

The weak attraction between a hydrogen atom and another atom

Solution

Type of mixture in which all the components are evenly distributed

Buffer

A solution which resists changes in pH

Carbohydrates

Organic compounds providing energy for animals

Lipids

Fatty organic compounds not soluble in water

Nucleic acids

Organic compounds made up of nucleotides that store and transmit hereditary information

Nucleotides

Consist of three parts; a 5-carbon sugar, a phosphate group, and a nitrogen base

Proteins

Organic compounds made up of amino acids; needed by the body for growth and repair

Amino acids

A compound with an amino group and carboxyl group used to build proteins

Activation energy

Energy required to initiate a chemical reaction

Catalyst

Substance that increases rate of chemical reaction

Enzymes

A type of protein that acts as a biological catalyst

Substrates

The reactants that enter a chemical reaction of an enzyme or enzyme-catalyzed reaction