| A | B |
|---|
| cell | The basic unit of structure and function in living things. |
| microscope | An instrument that makes small objects look larger. |
| cell theory | A widely accepted explanation of the relationship between cells and living things. |
| organelle | A tiny cell structure that carries out a specific function within the cell. |
| cell wall | A rigid layer of nonliving material that surrounds the cells of plants and some other organisms. |
| cell membrane | A cell structure that controls which substances can enter or leave the cell. |
| nucleus | A cell structure that carries out a specific function within the cell. |
| cytoplasm | The region between the cell membrane and the nucleus; in organisms without a nucleus, the region located inside the cell membrane. |
| mitochondria | Rod-shaped cell structures that convert energy in food molecules to energy the cell can use to carry out functions. |
| endoplasmic reticulum | A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another. |
| ribosome | A small grain-like structure in the cytoplasm of a cell where proteins are made. |
| Golgi body | A structure in a cell that receives proteins and other newly formed materials from the endoplasmic reticulum, packages them, and distributes them to other parts of the cell. |
| chloroplast | A structure in the cells of plants and some other organisms that captures energy form sunlight and uses it to produce food. |
| vacuole | A sac inside a cell that acts as a storage area. |
| lysosome | A small, round cell structure containing chemicals that break down large food particles into smaller ones. |
| element | Any substance that cannot be broken down into simpler substances. |
| compound | Two or more elements that are chemically combined. |
| carbohydrate | Energy-rich organic compound, such as a sugar or a starch, that is made of the elements carbon, hydrogen, and oxygen. |
| protein | Large organic molecule made of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. |
| amino acid | A small molecule that is linked chemically to other amino acids to form proteins. |
| enzyme | A type of protein that speeds up a chemical reaction in a living thing. |
| lipid | Energy-rich organic compound, such as a fat, oir, or waz, that is made of carbon, hydrogen, and oxygen. |
| nucleic acid | Very large organic molecule made of carbon, oxygen, hydrogen, nitrogen, and phosphorus, that contains the instructions cells need to carry out all the functions of life. |
| DNA | Deoxyribonucleic acid; the genetic material that carries information about an organism and is passed from parent to offspring. |
| RNA | Ribonucleic acid; a nucleic acid that plays an important role in the production of proteins. |
| selectively permeable | A property of cell membranes that allows some substances to pass through, while others cannot. |
| diffusion | The process by which 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 materials through a cells membrane without using energy. |
| active transport | The movement of materials through a cell membrane using cellular energy. |
