Using the table below, distinguish between rod cells and cone cells.

Outline how sound is perceived in the ear.

Award [1] for each correct row.

sound waves make eardrum/tympanic membrane vibrate;

vibration passes along the bones of middle ear/ossicles/malleus, incus and stapes making oval window vibrate;

vibration passed to fluid in cochlea;

vibration in cochlea stimulate hair cells/mechanoreceptors;

nerve impulse passed to auditory nerve;

Although this seemed like an easy question, comments on the G2 forms indicated that the wording of the question was such that it was not clear what was required under ‘characteristics’. In retrospect, candidates did do poorly on this as many earned only one mark for correctly identifying the different light intensities detected by rods and cones. A surprising number could not identify the fovea as the location of the cones. The connection to the optic nerve was answered correctly only by the better candidates. Perhaps the use of the optic nerve was confusing and bipolar neuron would have been clearer.

This is a question that occurred frequently. Outlining how sound is perceived by the ear was well done by the majority of candidates, with full marks often awarded.