| A | B |
|---|
| chromatin | granular material visible within the nucleus; consists of DNA tightly coiled around proteins |
| chromosome | threadlike structure within the nucleus containing the genetic 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 made of protein that maintains cell shape and can also serve as a “track” along which organelles are moved |
| microfilament | long, thin fiber made of protein that functions in the movement and support of the cell |
| cilia | short hair-like projections made from microtubules that can be used for cell movement – there are usually many cilia per cell |
| flagella | long hair-like projections made from microtubules that can be used for cell movement – there are usually one or two flagella per cell |
| ribosome | small particle in the cell on which proteins are assembled; made of RNA and protein |
| rough endoplasmic reticulum | folded membrane studded with ribosomes where proteins are chemically modified |
| smooth endoplasmic reticulum | folded membrane that does not have ribosomes attached to it – it contains enzymes that perform tasks like making lipids |
| 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 stores materials such as water, salts, proteins, and carbohydrates |
| plastid | a general name for an organelle that stores pigments and starch |
| chromoplast | a type of plastid that stores pigments |
| leucoplast | a type of plastid that stores starch |
| chloroplast | organelle found in cells of plants and some other organisms that uses energy from sunlight to make energy-rich food molecules by photosynthesis |
| mitochondrion | cell organelle that releases energy stored in food molecules and converts in into ATP; also known as the “powerhouse of the cell” |
