Biology Prefixes and Cell Words: Hyper/Hypo, Endo/Exo, -cyte

Decode biology terms built from paired prefixes and the root for cell.

Biology frequently uses prefix pairs that are opposites, so learning one teaches you two. Hyper- means over or above normal; hypo- means under or below. Hyperthermia is dangerously high body temperature; hypothermia is dangerously low. Endo- means within; exo- means outside. An endoskeleton is inside the body, like ours; an exoskeleton is outside, like an insect's. The root cyte, from Greek kytos, 'hollow vessel,' means cell: erythrocyte (erythros, 'red') is a red blood cell, leukocyte (leukos, 'white') is a white blood cell.

Plasm means formed material, as in cytoplasm, the material inside a cell. Worked example: 'Thyroid disorders can cause hyperthyroidism or hypothyroidism. ' The single letter difference, e versus o, flips the meaning from an overactive gland to an underactive one. Read these prefixes slowly; they look nearly identical but mean opposite things.

• 1Hyper- is over; hypo- is under.
• 2Endo- is within; exo- is outside.
• 3-cyte means cell; plasm means formed material.