| A | B |
|---|
| cell wall | the definite boundary or wall that is part of the outer structure of the cell |
| endoplasmic reticulum | a network of tubular membranes that is involved in the transport of materials within the cell |
| vacuole | A small cavity in the cytoplasm of a cell, which contains water, food or waste. |
| mitochondrion | an organelle in the cytoplasm of cells that functions in energy production |
| nucleus | a central part of the cell with a double membrane that directs the growth, metabolism and reproduction of the cell |
| ribosome | a tiny part of the cell that produces protein |
| cell membrane | a thin layer that encloses the cell and controls what goes in and out of the cell |
| cytoplasm | the cell substance between the cell membrane and the nucleus, it is full of proteins that control cell metabolism |
| lysosomes | a part of the cell that breaks down food molecules |
| golgi bodies | a part of the cell that’s function is to prepare and store chemical products in the cell, and to secrete these outside the cell |
| atmosphere | The gaseous envelope surrounding the earth. |
| troposphere | The first layer above the surface and contains half of the Earth's The first layer above the surface and contains half of the Earth's The first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer. |
| stratosphere | The region of the upper atmosphere characterized by little change in temperature as you go up. |
| mesosphere | The portion of the atmosphere above the earth's surface, characterized by temperatures that decrease as you go up. |
| thermosphere | The region of the upper atmosphere in which temperature increase as you go up. |
| ionosphere | Part of the thermosphere but very important. This area makes long distance radio communication possible by reflecting radio waves back to Earth. |
| exosphere | Where the atmosphere merges into space. This is the upper limit of our atmosphere and extremely thin. |
| ozone layer | A region of the upper atmosphere containing a high concentration of ozone that absorbs solar radiation. |
| meteorology | the science dealing with the atmosphere and its phenomena, including weather and climate. |
| aurora borealis | a display of colored lights in the sky, also called northern lights, caused by the interaction of particles from the sun with the upper atmosphere. |
