| Questions | 5 |
| Topics | Atomic Number, Cytoplasm, Periods, Species Groups, Terrestrial Planets |
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 |
The rows of the Periodic Table are called periods and contain elements that have the same number of electron shells ordered from lower to higher atomic number.
A population is a group of organisms of the same species who live in the same area at the same time. A community is a group of populations living and interacting with each other in an area.
The four planets closest to the Sun (Mercury, Venus, Earth, and Mars) are called terrestrial (Earth-like) planets because, like the Earth, they're solid with inner metal cores covered by rocky surfaces.