Interactions with environmentIB MYP Biology: Topic test

1. 1
   A goalkeeper in Buenos Aires sees a ball flying towards her and dives to catch it.

   (a)

   Which part of the goalkeeper's body acts as the receptor that detects the ball?

   [1 mark]

   • AThe muscles of her arm
   • BHer brain
   • CThe light-sensitive cells in her eye
   • DThe motor neurones in her spinal cord

   (b)

   Which part of the goalkeeper's body is the effector in this response?

   [1 mark]

   • AThe muscles in her arms and legs
   • BThe sensory neurone from her eye
   • CHer brain
   • DThe light-sensitive cells in her eye

   (c)

   Describe the pathway that nerve impulses take from the receptor to the effector.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   An optician in Mexico City examines a patient whose cornea is scratched. The patient says that everything looks blurred, but tests show that her retina and optic nerve are healthy.

   (a)

   What is the main function of the cornea?

   [1 mark]

   • ATo control how much light enters the eye
   • BTo detect light and send impulses to the brain
   • CTo carry impulses from the eye to the brain
   • DTo bend (refract) light as it enters the eye

   (b)

   In which structure is the image focused so that light-sensitive cells can detect it?

   [1 mark]

   • AThe iris
   • BThe retina
   • CThe optic nerve
   • DThe lens

   (c)

   Explain why a scratched cornea makes the patient's vision blurred even though her retina is healthy.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A 10-year-old boy in Lima is much shorter than his classmates. Tests show that his pituitary gland releases too little growth hormone. Doctors treat him with regular injections of the hormone, and his growth speeds up gradually over several months.

   (a)

   Describe how growth hormone reaches its target organs and explain why the boy's growth responds much more slowly than a reflex.

   [3 marks]

   (b)

   Compare control by the nervous system with control by hormones.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Gardeners in Morocco notice that the roots of some trees grow sideways towards leaking irrigation pipes buried in the soil. A student thinks the roots are detecting water. A farming cooperative is now considering installing buried drip irrigation pipes on its olive farm, which would water the soil deep underground rather than spraying the surface.

   (a)

   Design an investigation to test whether roots grow towards water.

   [6 marks]

   (b)

   Discuss whether the cooperative should install buried drip irrigation on its olive farm.

   [6 marks]

   Total for question 4: 12 marks

5. 5
   The venom of a cone snail in the Indian Ocean contains a toxin that blocks the transmission of impulses across the synapses between neurones. A diver stung by the snail finds that his muscles gradually stop responding to messages from his brain.

   (a)

   What happens at a synapse?

   [1 mark]

   • AImpulses speed up as they pass between two neurones
   • BA chemical passes across the gap between two neurones
   • CTwo neurones fuse to form one neurone
   • DImpulses change into hormones in the blood

   (b)

   Which part of the nervous system is made up of the brain and the spinal cord?

   [1 mark]

   • AThe effectors
   • BThe nerves
   • CThe sensory neurones
   • DThe central nervous system

   (c)

   Explain why the diver's muscles stop responding to messages from his brain.

   [2 marks]

   Total for question 5: 4 marks

6. 6
   Hassan, a 12-year-old in Riyadh, can see distant objects clearly, but the print in a book is blurred. His optician explains that light from nearby objects is brought to a focus behind his retina.

   (a)

   What is Hassan's eye defect?

   [1 mark]

   • ALong sight
   • BShort sight
   • CA faulty pupil reflex
   • DA damaged optic nerve

   (b)

   Which type of lens would correct Hassan's vision?

   [1 mark]

   • AA concave lens, which spreads light rays out
   • BA flat lens, which does not bend light
   • CA convex lens, which brings light rays together
   • DA tinted lens, which reduces the brightness

   (c)

   Suggest two reasons why light from nearby objects is focused behind Hassan's retina.

   [2 marks]

   Total for question 6: 4 marks

7. 7
   A man in Lahore has a small tumour in his adrenal glands that makes them release too much adrenaline all the time. Over one week his resting heart rate averaged 108 beats per minute, while the normal resting range is 60 to 80. Six weeks after surgery to remove the tumour, his resting heart rate averaged 74 beats per minute.

   (a)

   Describe how adrenaline released by the adrenal glands reaches the heart and what effect it has there.

   [3 marks]

   (b)

   Evaluate whether these results show that the tumour caused the high heart rate.

   [4 marks]

   Total for question 7: 7 marks

8. 8
   Astronauts on the International Space Station grow wheat seedlings in sealed chambers. The station is in free fall, so there is almost no gravity inside, and the seedlings' roots and shoots grow in random directions. Identical seedlings grown on Earth have roots that grow downwards and shoots that grow upwards. Space agencies are investing heavily in growing food in space for long missions.

   (a)

   Explain how auxin makes shoots grow upwards and roots grow downwards on Earth, and why this does not happen on the space station.

   [6 marks]

   (b)

   Discuss whether space agencies should invest in growing food crops in space.

   [6 marks]

   Total for question 8: 12 marks

End of questions