| Questions | 5 |
| Topics | Atomic Number, Cytoplasm, Electron, Outer Planets, Species |
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.
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 electron is a subatomic particle that orbits the nucleus of an atom. It carries a negative electric charge. Generally, an atom has the same number of negative electrons orbiting the nucleus as it does positive protons inside.
In contrast to the solid terrestrial planets, the outer planets (Jupiter, Saturn, Uranus, and Neptune) consist of hydrogen and helium gas and water.
The narrowest classification of life, species, contains organisms that are so similar that they can only reproduce with others of the same species.