An organism made up of many cells.

The structure that separates the cell from its external environment.

The organelle that produces most of the energy that cells need.

The theory that microbes can cause infectious diseases.

This structure contains a eukaryotic cell's DNA.

The material that fills much of the inside of cells.

Cell structures, often surrounded by a separate membrane, that perform a specific function.

The structure that separates the nucleus from the rest of the cell.

Single-celled organisms that do not have a nucleus or other membrane-bound organelles.

The process in which oxygen is used to break down sugar from food.

A standard for comparison for checking or verifying the results of an experiment.

An organism made up of a single cell or many cells with a nucleus, and that is not an animal, plant, or fungus.