Term Definition
atom The smallest unit of an element that maintains the properties of that element.
carbon dioxide
carbohydrate A class of molecules that includes sugars, starches, and fiber; contains carbon, hydrogen, and oxygen.
cellular respiration The process by which cells use oxygen to produce energy from food.
chlorophyll A green pigment that captures light energy for photosynthesis.
chloroplast An organelle found in plant and algae cells where photosynthesis occurs.
energy The capacity to do work.
law A descriptive statement or equation that reliably predicts events under certain conditions.
Law of Conservation of Energy The law that states that energy cannot be created or destroyed but can be changed from one form to another.
Law of Conservation of Mass The law that states that mass cannot be created or destroyed in ordinary chemical and physical changes.
mass A measure of the amount of matter in an object.
matter Anything that has mass and takes up space.
molecule A group of atoms that are held together by chemical bonds; a molecule is the smallest unit of a substance that can exist by itself and retain all of the substance's chemical properties.
photosynthesis The process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to make food.
product A substance that forms in a chemical reaction.
reactant A substance that participates in a chemical reaction.
