The Chemical Level of Organization chapter 2 (Anatomy and Physiology)

Matter

Anything that has mass and takes up space.

Mass vs. Weight

Mass is the amount of matter; weight is gravity's force on it.

Atom

The smallest unit of matter that retains an element's properties.

Atomic Number

The number of protons in the nucleus of an atom.

Mass Number

The total number of protons and neutrons in an atom.

Ion

An atom that has lost or gained an electron.

Molecule

Two or more atoms sharing electrons.

Compound

A substance that can be broken down into different elements.

Ionic Bond

Attraction between oppositely charged ions.

Covalent Bond

A chemical bond formed by sharing electrons.

Hydrogen Bond

Attraction between oppositely charged parts of polar molecules.

Cohesion

The tendency of like particles to stay together.

Reactants

The starting substances in a chemical reaction.

Products

The ending substances in a chemical reaction.

Oxidation

The loss of electrons and energy release.

Reduction

The gain of electrons and energy.

Inorganic Compounds

Simple molecules that usually lack carbon.

Organic Compounds

Molecules that always contain carbon and hydrogen with covalent bonds.

Hydrolysis

A reaction where water is added to break chemical bonds.

Dehydration Synthesis

A reaction where water is removed to form chemical bonds.

Mixture

Elements or compounds physically blended together but not bonded.

Buffer Systems

Systems that regulate pH by converting strong acids or bases into weak ones.

Carbohydrates

Organic molecules that provide most of the energy needed for life.

Triglycerides

Lipids that provide protection, insulation, and stored energy.

Proteins

Large molecules formed by amino acids that provide structure and function.

Enzyme

A highly specific and efficient biological catalyst.

DNA

The nucleic acid that forms the genetic code in cell nuclei.

RNA

The nucleic acid that guides protein formation.

ATP

The principal energy-storing molecule in the body.