Flagella are found in both eukaryotic cells and prokaryotic cells. Despite the functional similarities of all flagella, scientists suspect that eukaryotic and prokaryotic flagella have evolved independently. Why don't they think there is a common evolutionary origin for prokaryotic and eukaryotic flagella?
A) Prokaryotic flagella do not protrude outside the cell wall, whereas eukaryotic flagella are membrane- bound extensions of cytoplasm.
B) Prokaryotic flagella do not require energy in the form of ATP.
C) Prokaryotic flagella move by rotating, whereas eukaryotic flagella undergo an undulating motion. Furthermore, eukaryotic flagella are covered by a plasma membrane and prokaryotic flagella are not.
D) Prokaryotic flagella are an adaptation to scarce nutrient supply, whereas eukaryotic flagella are designed to protect.

Question

Quizplus · Accepted Answer

Prokaryotic and eukaryotic flagella move in different ways (rotating versus undulating) and have different structures (eukaryotic flagella are membrane-bound while prokaryotic flagella are not), suggesting that they evolved independently. Additionally, prokaryotic flagella require energy in the form of ATP, so B is incorrect, and D is also incorrect as there is no evidence that eukaryotic flagella are designed to protect.

Flagella Are Found in Both Eukaryotic Cells and Prokaryotic Cells