Biological Systems MCAT Practice Exam

What part of the eye is primarily responsible for color detection?

1. Cornea

2. Rods

3. Cones

4. Ganglion cells

The correct answer is: Cones

The part of the eye primarily responsible for color detection is the cones. Cones are photoreceptor cells located in the retina and are specifically sensitive to different wavelengths of light, which correspond to the colors we perceive. There are three types of cones, each responding to different ranges of wavelengths—short (blue), medium (green), and long (red). This trichromatic system enables the brain to interpret a wide spectrum of colors based on the varying levels of activation of these cones. In contrast, rods, another type of photoreceptor in the retina, are responsible for vision in low light and do not contribute to color perception. They are more sensitive to light and motion, but do not distinguish colors. The cornea is the clear, outer layer of the eye that helps to focus light but does not play a role in color detection. Ganglion cells are the final output neurons of the retina, processing visual information but are not directly involved in color detection either. Their role involves transmitting information from the photoreceptors to the brain, integrating signals from the cones and rods to help in overall visual perception.