| A | B |
|---|
| element | any substance that cannot be broken down into simpler substances |
| compound | two or more elements combine chemically |
| carbohydrate | an energy-rich organic compound made of carbon, hydrogen, and oxygen. Examples are sugars and starches. |
| lipid | energy-rich organic compounds made of carbon, hydrogen, and oxygen. Fats, oils, and waxes are examples. |
| protein | large organic molecules made of carbon, hydrogen, oxygen, nitrogen, and in some cases sulfur. Foods that contain protein are meat, eggs, fish and nuts. |
| amino acid | protein molecules are made up of these smaller molecules |
| enzyme | a type of protein that speeds up a chemical reaction in a living thing |
| nucleic acid | very long organic molecules that contain the instructions cells need to carry out all the functions of life |
| DNA | the genetic material that carries information about an organism and is passed from parent to offspring |
| RNA | plays an important role in the production of proteins |
| selectively permeable | means that some substances can pass through the cell membrane, while others cannot |
| diffusion | the main method by which small molecules move across a cell membrane. Molecules move from an area of higher concentration, to an area of lower concentration |
| osmosis | the diffusion of water molecules through a selectively permeable membrane |
| passive transport | the movement of dissolved materials through a cell membrane without using cellular energy |
| active transport | the movement of materials through a cell membrane using cellular energy |
