| A | B |
|---|
| Chromatin | granular material visible within the nucleus; consists of DNA tightly coiled around proteins |
| Chromosome | threadlike structure within the nucleus containing the geneitc information that is passed from one generation of cells to the next |
| Nucleolus | small, dense region within most nuclei in which the assembly of ribosomes begins |
| Nuclear envelope | double-membrane layer that surrounds the nucleus of a cell |
| Cytoskeleton | network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement |
| Microtubule | hollow tube of protein that maintains cell shape and can also serve as a "track" along which organelles are moved |
| Microfilament | long, thin fiber that functions in the movement and support of the cell |
| Ribosome | small particle in the cell on which proteins are assembled; made of RNA and protein |
| Endoplasmic reticulum | internal membrane system in cells in which components of the cell membrane are assembled and some proteins are modified |
| Golgi apparatus | stack of membranes in the cell in which enzymes attach carbohydrates and lipids to proteins |
| Lysosome | cell organelle filled with enzymes needed to break down certain materials in the cell |
| Vacuole | cell organelle that stored materials such as water, salts, proteins, and carbohydrates |
| Chloroplast | organelle found in cells of plans and some other organisms that uses energy from sunlight to make energy-rich food molecules by photosynthesis |
| Mitochondrion | cell organelle that releases energy from stored food molecules |
