Which protist is characterized by a complex cell covering and two flagella?

Which protist is characterized by a complex cell covering and two flagella?

• A. Foraminifera
• B. Copepod
• C. Dinoflagellate
• D. Angiosperm

Answer: (C)

Two features define dinoflagellates: a complex cell covering called the theca, made of cellulose plates, and two flagella that drive their movement. One flagellum sits in a transverse groove around the cell and the other runs in a longitudinal groove, giving a distinctive spinning or thrashing motion as they swim. This combination—armored cell covering plus paired flagella in specific positions—is characteristic of dinoflagellates, a group of protists common in marine environments and often photosynthetic. Foraminifera have calcareous shells and move with pseudopodia rather than two flagella, copepods are crustaceans (not protists), and angiosperms are flowering plants. Thus, the protist with a complex cell covering and two flagella is the dinoflagellate.

Two features define dinoflagellates: a complex cell covering called the theca, made of cellulose plates, and two flagella that drive their movement. One flagellum sits in a transverse groove around the cell and the other runs in a longitudinal groove, giving a distinctive spinning or thrashing motion as they swim. This combination—armored cell covering plus paired flagella in specific positions—is characteristic of dinoflagellates, a group of protists common in marine environments and often photosynthetic. Foraminifera have calcareous shells and move with pseudopodia rather than two flagella, copepods are crustaceans (not protists), and angiosperms are flowering plants. Thus, the protist with a complex cell covering and two flagella is the dinoflagellate.