Cell
The structural and functional unit of life
Molecules
Particles composed of two or more joined atoms
Macromolecules
Large molecules, such as proteins or nucleic acids
Organelles
Structures in cells that have specialized functions
Tissue
Groups of similar cells that perform a specialized function
Organs
Structures consisting of a group of tissues with a specialized function
Organ systems
A group of organs coordinated to carry on a specialized function
Organism
An individual living thing
Anatomy
The branch of science that deals with the structure (morphology) of body parts -- their forms and how they are organized
Metabolism
All of the chemical reactions in cells that break down or build up substances
Atoms
Smallest particles of an element that have properties of that element, which join to form molecules
Physiology
The branch of science that concerns the function of the body parts -- what they do and how they do it