Atom
Basic unit of matter
Molecule
A group of atoms bonded together
Macromolecules
A very large organic molecule composed of many smaller molecules
Organelle
A tiny cell structure that carries out a specific function within the cell
cell
Basic unit of life
Tissue
A group of similar cells that perform the same function.
Organ
group of tissues that work together to perform closely related functions
organ system
group of organs that work together to perform a specific function
Organism
composed of organ systems interacting
Movement
Change in position of the body or of a body part; motion of an internal organ
Responsiveness
Reaction to a change inside or outside the body
Growth
increase in size without change in shape
Reproduction
production of new organisms and new cells
Respiration
obtaining oxygen, removing carbon dioxide, and releasing energy from foods
Digestion
Breakdown of food substances into simpler forms that can be absorbed and used
absorption
The process by which nutrient molecules pass through the wall of the digestive system into the blood
circulation
movement of substances in body fluids
assimilation
changing absorbed substances into chemically different forms
Excretion
Process by which metabolic wastes are eliminated from the body