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How do flagella help some algae move through water?

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“mermaid's wine glass” algae — Algae The macroscopic genus of algae known as *Acetabularia* is commonly called “mermaid's wine glass” because of the distinctive umbrella-like shape of the tips of its stalks.

Flagella facilitate movement in algae through a complex, energy-dependent process involving the conversion of chemical energy from adenosine triphosphate (ATP) into mechanical energy.12

The structure of the eukaryotic flagellum consists of an axoneme with a "nine-plus-two" arrangement of microtubules. Movement is driven by the protein dynein, which is attached to the microtubules. When activated by ATP, dynein arms create cross-bridges that slide along the microtubules, causing the flagellum to bend. This coordinated sliding produces a characteristic whiplike motion.132

These undulations generate waves that travel along the flagellum, exerting force on the surrounding water. Depending on the species, the movement may manifest as planar waves, oarlike beating, or three-dimensional, propeller-like rotations. Additionally, some algae possess superficial hairs or scales, such as mastigonemes, which increase the effectiveness of the flagellar stroke by altering the flow of water, thereby aiding in locomotion. The entire structure is anchored to the cell by a basal body, which provides the necessary stability for these movements.3412