The whale's ability to hold its breath is, in a way, an evolutionary one-two punch: (1) The high concentration of myoglobin allows it to spend more time underwater in between breaths, and (2) the myoglobin's positive charge ensures the proteins don't clump together and kill the animal.
Lesson Summary. Let's review. A flagellum is a whip-like structure that allows a cell to move. They are found in all three domains of the living world: bacteria, archaea, and eukaryota.While all three types of flagella are used for locomotion, they are structurally very different.The eukaryotic flagellum is a long, rod-like structure that is surrounded by an extension of the cell membrane like a sheath.t is similar to a cilium in structure, though cilia generally move in a back and forth motion, as opposed to the corkscrew movement of a flagellum. The eukaryotic flagellum is a long, rod-like structure that is surrounded by an extension of the cell membrane like a sheath.
The group includes flagellates (which move with the help of whip-like structures called flagella), ciliates (which move by using hair-like structures called cilia) and amoebae (which move by the use of foot-like structures called pseudopodia).he group was regarded as the zoological counterpart to the  protophyta , which were considered to be plant-like, as they are capable of photosynthesis. The terms protozoa and protozoans are also used informally to designate single-celled, non-photosynthetic protists, such as ciliates, amoebae and flagellates.