| Questions | 5 |
| Topics | Atomic Number, Circulation, Cytoplasm, Solid, Veins |
The Periodic Table of the Elements categorizes elements primarily by the number of protons in their nucleus (atomic number) and secondarily by the characteristics they exhibit.
Like the respiratory system, the circulatory system serves to transport oxygen throughout the body while removing carbon dioxide. In addition, the circulatory system transports nutrients from the digestive system.
The nucleus of a eukaryotic cell contains the genetic material of the cell and is surrounded by cytoplasm which contains many organelles. These include:
| Organelle | Function |
|---|---|
| ribosomes | produce proteins |
| mitochondria | produce energy |
| endoplasmic reticulum | helps synthesize proteins and fats |
| Golgi apparatus | prepare proteins for use |
| lysosomes | help the cell manage waste |
| centrosomes | guide cell reproduction |
An element in a solid state has atoms or molecules that are constricted and do not move freely. Solids maintain a constant volume and shape and exist at a lower temperature than liquids or gases.
Veins carry blood back to the heart from the body. While arteries are thick-walled because they carry oxygenated blood at high pressure, veins are comparatively thin-walled as they carry low-pressure deoxygenated blood. Like the heart, veins contain valves to prevent blood backflow.