[Campbell Biology P.650] Based on Figure 28.10 and the accompanying text, what is the primar... | Practice Question

Based on Figure 28.10 and the accompanying text, what is the primary function of the eyespot and light detector in Euglena, and how does the pellicle contribute to its cellular characteristics?

  • A: The eyespot is for vision, and the light detector regulates photosynthesis; the pellicle is a rigid cell wall for protection.
  • B: The eyespot acts as a light shield allowing light from a specific direction to strike the light detector, enabling movement towards optimal light for photosynthesis; the pellicle provides strength and flexibility.
  • C: The eyespot absorbs light for energy, and the light detector stores excess light; the pellicle aids in nutrient absorption.
  • D: Both the eyespot and light detector are involved in prey capture; the pellicle facilitates rapid cell division.

Explanation

Figure 28.10 clearly labels the eyespot as a 'pigmented organelle that functions as a light shield' and the light detector as a 'swelling near the base of the long flagellum; detects light that is not blocked by the eyespot. As a result, Euglena moves toward light of appropriate intensity, an important adaptation that enhances photosynthesis.' The pellicle is described as 'protein bands beneath the plasma membrane that provide strength and flexibility'.