OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Which type of receptor is responsible for detecting light?

1. Touch receptors

2. Temperature receptors

3. Receptors in the eyes

4. Chemical receptors

The correct answer is: Receptors in the eyes

The type of receptor responsible for detecting light is found in the eyes, specifically in structures called photoreceptors. These photoreceptors, which include rods and cones, are specialized cells that convert light into neural signals that the brain can interpret as visual information. Rods are sensitive to low light levels and are important for night vision, while cones function in daylight and are responsible for color vision and visual acuity. In contrast, touch receptors are specialized for sensing mechanical changes in the environment, such as pressure or vibration. Temperature receptors detect changes in thermal conditions. Chemical receptors, such as those involved in taste and smell, respond to specific molecules rather than light. Therefore, receptivity to light is distinctly a function of the specialized receptors located within the eyes.