The structure of algae varies depending on the type of algae, but most algae have a few basic components:

1. Cell wall: Algae have a cell wall that provides structural support and protection to the cell.
2. Nucleus: The nucleus contains the genetic material (DNA) of the algae.
3. Chloroplasts: Chloroplasts are the organelles in algae that contain chlorophyll, which is used to perform photosynthesis.
4. Vacuoles: Vacuoles are large, fluid-filled structures that help maintain the shape of the cell and store nutrients and waste.
5. Mitochondria: Mitochondria are the powerhouses of the cell and are responsible for producing energy for the cell.
6. Endoplasmic reticulum and Golgi apparatus: These organelles play a role in protein synthesis and processing.

The structure of algae can range from simple, unicellular organisms to complex, multicellular structures. Some algae are filamentous, meaning they are composed of chains of cells, while others are branched or have a more elaborate branching system.