1. 1
   A student touches a hot pan by accident and pulls their hand away before feeling any pain. A doctor explains that this rapid withdrawal is a reflex action controlled by a reflex arc, not a decision made by the brain.

   (a)

   Which type of neurone carries the impulse from the receptor in the skin towards the spinal cord?

   [1 mark]

   • ASensory neurone
   • BRelay neurone
   • CMotor neurone
   • DEffector neurone

   (b)

   Within the spinal cord, the impulse passes through a relay neurone before reaching the motor neurone. What is the main advantage of the reflex arc bypassing conscious processing in the brain?

   [1 mark]

   • AIt allows the response to be consciously controlled and delayed
   • BIt allows the student to remember the incident more clearly
   • CIt increases the amount of neurotransmitter released at the synapse
   • DIt allows the response to happen faster, reducing the risk of injury

   (c)

   Describe the pathway of the reflex arc from the sensory receptor in the skin to the effector muscle that withdraws the hand, naming the structures involved in the correct order.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   An optician tests a patient's eyes and finds that light entering the eye is focused in front of the retina rather than directly on it, so the patient can see nearby objects clearly but distant objects appear blurred.

   (a)

   Which eye defect does this describe?

   [1 mark]

   • ACataracts
   • BLong-sightedness (hyperopia)
   • CShort-sightedness (myopia)
   • DColour blindness

   (b)

   The optician recommends corrective lenses to treat this condition. What type of lens is needed, and how does it correct the defect?

   [1 mark]

   • AA convex (converging) lens, which bends light more strongly so it focuses further forward, onto the retina
   • BA concave (diverging) lens, which spreads light out before it enters the eye so it focuses further back, onto the retina
   • CA concave lens, which increases the amount of light entering the pupil
   • DA convex lens, which reduces the amount of light reaching the cornea

   (c)

   Explain why the shape of the eyeball or the shape of the lens can cause light to be focused in front of the retina instead of on it.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A patient suffers a head injury in a car accident and doctors suspect damage to the cerebellum.

   (a)

   Describe the normal function of the cerebellum and explain what symptoms this patient might show if it is damaged.

   [3 marks]

   (b)

   The doctors want to confirm exactly which part of the brain has been affected before deciding on treatment, but the brain is enclosed within the skull. Explain how CT scanning and PET scanning can help doctors investigate brain function in this patient, and describe one limitation of treating damage to the nervous system.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A school science club investigates stem cells in animals and meristems in plants. One student states that stem cell research offers only benefits with no risks, while another disagrees.

   (a)

   Discuss the potential benefits and risks associated with the use of stem cells in medicine, evaluating whether the first student's view is justified.

   [6 marks]

   (b)

   The science club also compares stem cells in animals with meristems in plants. Explain the differences between the roles of stem cells in animals and meristems in plants, and discuss why plant meristems can continue producing new specialised cells throughout the plant's life while most animal stem cells become more limited in this ability with age.

   [6 marks]

   Total for question 4: 12 marks

End of questions