Biology GCSE Edexcel: The Eye Exam
Questions With Correct Answers
What is the eye? - ANSA sense organ that contains receptor cells found in a layer called the retina
and allows you to see.
What are cones? - ANSReceptor cells in the retina that are sensitive to the colour of light. Cones can
detect red, green and blue light.
How do cones work? - ANSThey generate impulses in sensory neurones, which lead into the brain via
the optic nerve. The information from all the cones is processed into full colour vision at the back of
the cerebral hemispheres.
What are rods? - ANSReceptor cells in the retina that detect differences in light intensity (not colour).
Compare how both rods and cones work in dim light and bright light. - ANSRods work well in very
dim light whereas cones only work well in bright light. This is why your colour vision in quite bad in
dim lighting.
What is the structure of the eye? (starting from the front of the eye to the back) - ANSConjunctiva,
cornea, pupil, iris, ciliary muscle, suspensory ligament, lens, retina, fovea, optic nerve
What is the function of the cornea? - ANSTo refract light into the eye and protect it.
What is the function of the iris? - ANSTo control the diameter and size of the pupil and thus the
amount of light reaching the retina.
What is the function of the lens? - ANSTo focus light onto the retina.
What is the function of the optic nerve? - ANSTo transfer visual information from the retina to the
vision centres of the brain via electrical impulses. The optic nerve is a bundle of sensory neurones.
Questions With Correct Answers
What is the eye? - ANSA sense organ that contains receptor cells found in a layer called the retina
and allows you to see.
What are cones? - ANSReceptor cells in the retina that are sensitive to the colour of light. Cones can
detect red, green and blue light.
How do cones work? - ANSThey generate impulses in sensory neurones, which lead into the brain via
the optic nerve. The information from all the cones is processed into full colour vision at the back of
the cerebral hemispheres.
What are rods? - ANSReceptor cells in the retina that detect differences in light intensity (not colour).
Compare how both rods and cones work in dim light and bright light. - ANSRods work well in very
dim light whereas cones only work well in bright light. This is why your colour vision in quite bad in
dim lighting.
What is the structure of the eye? (starting from the front of the eye to the back) - ANSConjunctiva,
cornea, pupil, iris, ciliary muscle, suspensory ligament, lens, retina, fovea, optic nerve
What is the function of the cornea? - ANSTo refract light into the eye and protect it.
What is the function of the iris? - ANSTo control the diameter and size of the pupil and thus the
amount of light reaching the retina.
What is the function of the lens? - ANSTo focus light onto the retina.
What is the function of the optic nerve? - ANSTo transfer visual information from the retina to the
vision centres of the brain via electrical impulses. The optic nerve is a bundle of sensory neurones.
