A protein that increases the rate of a chemical reaction without being changed by the reaction; an organic catalyst.

• Enzyme
• Energy Pyramid
• Endocytosis

The basic unit of structure and function for all living organisms. Cells have three common components: genetic material, cytoplasm, and a cell membrane. Eukaryotic cells also contain specialized organelles.

• Cell
• Carbohydrate
• Biosphere

A macromolecule that contains atoms of carbon, hydrogen, and oxygen in a 1:2:1 ratio and serves as a major source of energy for living organisms (e.g., sugars, starches, and cellulose).

• Carbohydrate
• Biosphere
• Biological Macromolecules

An explanation of observable phenomena based on available empirical data and guided by a system of logic that includes scientific laws; provides a system of assumptions, accepted principles, and rules of procedure devised to analyze, predict, or otherwise explain the nature or behavior of a specific set of phenomena.

• Theory (Scientific)
• System
• Specific Heat

A single-celled organism that lacks a membrane?bound nucleus and specialized organelles.

• Prokaryote
• Population Dynamics
• Point Mutation

A group of individuals of the same species living in a specific geographical area and reproducing.

• Population
• Plastids
• Phenotype

Water having opposite charges

• Polarity
• Cohesion
• Water Cycle

A type of organism composed of one or more cells containing a membrane?bound nucleus, specialized organelles in the cytoplasm, and a mitotic nuclear division cycle.

• Eukaryote
• Energy Transformation
• Endoplasmic Reticulum (ER)

A system composed of organisms and nonliving components of an environment.

• Ecosystem
• DNA Replication
• Decomposer

Enzymes lower this to speed up reactions

• Activation Energy
• Hydrolysis
• Active Transport