Observing bacteria in a Petri dish.
Algae use sunlight and carbon dioxide to produce sugars (photosynthesis) which they use for energy. They can be very small or very big! They can be 10,000 times smaller than a pin head or as long as an airplane. Algae are usually green, but you can find red, brown and golden algae, depending on the types of pigment present. There are different types of algae too - filamentous, colonial and unicellular algae.
Some algae have flagella, which are long hair-like projections on the side of the cell wall that enable them to move. Algae contain chloroplasts - the photosynthetic reaction centre within an algal cell. Chloroplasts are membrane-bound organelles that contain chlorophyll, the molecule responsible for photosynthesis.
Algae can be observed using unstained wet mounts.
Filamentous algae are made up of individual cells that stick together in a chain-like series.
Colonial algae stick together to form colonies, forming many different shapes.
Unicellular algae are single cells that do not attached to each other.