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CAIE A Level Biology 9700

Control and coordination questions

Exam-style questions on Control and coordination, ordered from foundation to challenge. Pick one, write your answer the way you would in the exam, and it comes back marked against the mark scheme, point by point.

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Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.

  1. Explain4 marksStandardA student investigates the effect of increasing stimulus intensity on the frequency of action potentials in a sensory neurone. She observes that even with a very strong stimulus, the maximum frequency reaches a plateau…
  2. Outline5 marksStandardAn experiment was carried out to investigate the effect of auxin on cell elongation in stem segments of a plant. Segments of equal initial length were placed in buffer solution; one set was treated with auxin and the…
  3. Describe4 marksStandardDescribe the role of calcium ions (Ca²⁺) in the transmission of a nerve impulse across a cholinergic synapse.
  4. Compare5 marksStandardCompare the nervous and endocrine systems. In your answer, refer to: method of transmission speed of response duration of effect nature of the signal Give one specific example of a hormone (such as ADH, glucagon, or…
  5. Explain5 marksStandardIn a laboratory, the conduction velocities of two sensory neurones from a frog were compared. Neurone A had a myelin sheath, while neurone B did not. The results showed that the action potential in neurone A travelled…
  6. Explain4 marksStandardThe Venus fly trap (Dionaea muscipula) captures prey using modified leaves that form a trap. Each lobe of the trap bears several sensory hairs. When an insect touches a single sensory hair, an action potential is…
  7. Explain4 marksStandardTwo sensory neurones of the same diameter are isolated from a mammal. One is myelinated and the other is unmyelinated. When a stimulus of the same strength is applied to each neurone, the action potential travels more…
  8. Describe4 marksStandardDescribe four features that distinguish the nervous system from the endocrine system.
  9. Explain5 marksStandardA student investigates the effect of auxin on cell elongation in maize coleoptiles. When coleoptile segments are placed in a buffer solution containing auxin, the pH of the solution drops over time. Explain the…
  10. Explain5 marksStandardIn an experiment, segments of oat coleoptiles were placed in a solution containing auxin. The pH of the solution surrounding the cell walls was measured over time. Within minutes, the pH decreased from 7.0 to 5.5…
  11. Compare4 marksStandardA student investigates the effect of myelination on the speed of impulse conduction. They compare two nerve fibres: fibre A is a myelinated neurone from a frog, fibre B is a non-myelinated neurone from an earthworm…
  12. Describe5 marksStandardBarley seeds store food reserves in the endosperm as starch. During germination, the embryo produces gibberellin. Describe how gibberellin brings about the mobilisation of these starch stores to provide sugars for the…
  13. Compare5 marksStandardIn response to a sudden loud noise, a person quickly turns their head. In response to a rise in blood glucose concentration after a meal, the body releases insulin to lower blood glucose. Compare how the nervous system…
  14. Outline5 marksStandardAn experiment was carried out to investigate the effect of auxin on cell elongation in oat coleoptile segments. Segments of equal length (5.0 mm) were placed in either a control solution (buffer only) or a solution…
  15. Compare4 marksStandardA labelled diagram of a sarcomere from striated muscle shows the arrangement of actin and myosin filaments, with Z-lines, M-line, A-band, I-band, and H-zone clearly marked. Calcium ions are crucial for two processes…
  16. Outline4 marksStandardThe table below shows the increase in length of coleoptile segments incubated in different conditions for 2 hours. Condition Increase in length / mm pH 7, no auxin 2.0 pH 7, auxin (10⁻⁶ M) 4.5 pH 5, no auxin 8.0 pH 5…
  17. Compare4 marksStandardCompare the nervous system and the endocrine system of mammals.
  18. Describe4 marksStandardA student observes a Venus fly trap (Dionaea muscipula) in a laboratory. A small insect lands on one of the modified leaves and brushes against two of the trigger hairs within 20 seconds. The trap then snaps shut…
  19. Describe5 marksStandardBarley seeds store starch in the endosperm. Describe the role of gibberellin in mobilising these stored food reserves during germination.
  20. Describe5 marksStandardA student uses a microelectrode to record action potentials from a sensory neurone in a taste bud after applying solutions of increasing concentration of sodium chloride. The student observes that as the concentration…
  21. Describe4 marksStandardDescribe the sequence of events that leads to the rapid closure of a Venus fly trap leaf when the trigger hairs on the leaf lobes are touched twice.
  22. Outline4 marksStandardA student investigated the effect of auxin on stem elongation in tomato seedlings. The table below shows the mean increase in stem length after 24 hours for segments treated with auxin and untreated controls. Treatment…
  23. Describe5 marksStandardAn electron micrograph of a relaxed sarcomere from striated muscle shows a broad I-band and a prominent H-zone. Describe the sequence of events during contraction of this sarcomere according to the sliding filament…
  24. Explain4 marksStandardThe Venus fly trap (Dionaea muscipula) captures insects by rapidly closing its modified leaf lobes. Each lobe has sensitive hairs. If a single hair is touched once, the trap does not close. However, if the same hair is…
  25. Describe5 marksStandardDescribe the role of calcium ions (Ca2+) in the transmission of a nerve impulse across a cholinergic synapse.
  26. Explain5 marksStandardExplain the role of calcium ions in the transmission of impulses across a cholinergic synapse.
  27. Compare5 marksStandardCompare the roles of calcium ions in the following two processes: (i) The transmission of a signal from a taste bud chemoreceptor to a sensory neurone, following detection of a sweet taste. (ii) The stimulation of…
  28. Outline4 marksStandardA student investigated the effect of auxin on stem elongation in pea seedlings. Segments of stem were incubated in a buffered solution with or without auxin (indole-3-acetic acid). The length of each segment was…
  29. Explain5 marksStandardAn experiment investigates the effect of auxin on cell elongation in oat coleoptile segments. Segments are placed in a buffer solution at pH 7. Upon addition of auxin, the pH of the solution decreases to pH 5 within a…
  30. Outline5 marksStandardThe table below shows the mean cell length of coleoptile segments (plant shoots) treated with auxin and untreated control over time. Time (min) Mean cell length (µm) – untreated control Mean cell length (µm) – auxin…
  31. Explain4 marksStandardA person eats a food containing chemicals that are detected by taste bud chemoreceptors on the tongue. Explain the sequence of events that leads from the detection of a chemical stimulus by a taste bud chemoreceptor to…
  32. Compare7 marksChallengeStriated muscle contraction is controlled by calcium ions within the sarcomere. In a cholinergic synapse, calcium ions are also essential for signal transmission. Compare the role of calcium ions in these two processes.
  33. Explain6 marksChallengeWhen an animal encounters a sudden threat, such as a predator, both the nervous system and the endocrine system are activated. Explain how the nervous system and the endocrine system differ in their mechanisms of…
  34. Describe5 marksChallengeThe table below shows the changes in membrane potential of a neurone during a single action potential. Time / ms Membrane potential / mV 0.0 -70 0.5 -70 1.0 -55 1.5 +30 2.0 +10 2.5 -20 3.0 -50 3.5 -70 4.0 -75 4.5 -70…
  35. Describe5 marksChallengeThe Venus fly trap (Dionaea muscipula) closes its modified leaves rapidly in response to mechanical stimulation of its trigger hairs. Describe the sequence of events from the initial stimulation of the trigger hairs to…
  36. Compare7 marksChallengeA student investigates the maximum frequency of impulse transmission in two preparations using isolated tissue from a mammal. Preparation 1: A single sensory neurone from a taste bud is stimulated directly. The maximum…
  37. Compare7 marksChallengeAfter a carbohydrate-rich meal, blood glucose concentration rises. Outline the roles of the nervous system and the endocrine system in coordinating the body's response to this rise, with reference to specific hormones…
  38. Explain6 marksChallengeA researcher treated isolated stem segments with auxin (IAA). She measured the pH of the cell wall space and the length of the segments over time. The results showed that the pH dropped from 5.5 to 4.5 within 15…
  39. Outline7 marksChallengeThe table below shows the mean stem elongation (mm) over 24 hours of etiolated pea seedlings treated with either distilled water (control) or 10⁻⁵ M auxin solution. Treatment Mean stem elongation (mm) Control 2.5 ± 0.3…
  40. Outline7 marksChallengeA student investigated the effect of auxin on cell elongation in coleoptile segments. Segments of equal initial length were placed in a solution containing auxin or in a control solution without auxin. After 24 hours…
  41. Describe5 marksChallengeA cholinergic synapse connects a presynaptic neurone to a postsynaptic neurone. An action potential arrives at the presynaptic terminal. Describe the role of calcium ions (Ca²⁺) in the transmission of the impulse…
  42. Explain6 marksChallengeA person eats a piece of fruit and detects a sweet taste. Explain the sequence of events that occurs from the binding of sugar molecules to chemoreceptors on a taste bud to the generation of an action potential in the…
  43. Explain6 marksChallengeVenus fly trap plants (Dionaea muscipula) capture insects by rapid closure of their modified leaves. The leaves have sensory hairs on the inner surface. When an insect touches a hair, an action potential is generated…
  44. Describe5 marksChallengeDescribe the role of gibberellin in mobilising stored food reserves during the germination of barley seeds.
  45. Outline7 marksChallengeTable 1 shows the effect of auxin on the elongation of stem segments incubated in buffer at pH 7 for 2 hours. Table 1 Treatment Mean increase in length / mm Control (buffer only) 0.3 Buffer + 1 µM auxin 1.2 (a) Outline…
  46. Explain6 marksChallengeIn the Venus fly trap (Dionaea muscipula), the modified leaves close rapidly when prey touches the trigger hairs. The plant does not close after a single touch but only if two touches occur within about 20 seconds…
  47. Explain6 marksChallengeIn a comparative study, researchers measured the conduction velocity of action potentials along two types of neurones from the same mammal. Type A is a myelinated motor neurone; Type B is an unmyelinated sensory…
  48. Describe5 marksChallengeA person tastes a piece of sweet fruit. Describe the sequence of events that occur from the binding of a sweet-tasting molecule to a chemoreceptor on a human taste bud cell to the generation of an action potential in…
  49. Describe5 marksChallengeDescribe the sequence of events that leads to the closure of a Venus fly trap leaf when its trigger hairs are touched twice within a short time. In addition, describe the role of auxin in stimulating cell elongation in…
  50. Describe5 marksChallengeDuring barley seed germination, gibberellin is essential for mobilising stored food reserves. Describe the role of gibberellin in this process, including the origin of the hormone, its target cells, and the resulting…
  51. Outline7 marksChallengeA student investigated the effect of auxin (IAA) on cell elongation in oat coleoptile segments. Segments were placed in buffer solutions with different IAA concentrations. After 2 hours, the length of the segments and…
  52. Compare7 marksChallengeCalcium ions play a crucial role in both synaptic transmission and muscle contraction. Compare the role of calcium ions in the transmission of an impulse across a cholinergic synapse with the role of calcium ions in…
  53. Explain6 marksChallengeExplain how the nervous system and the endocrine system differ in their mode of action and the nature of the responses they produce. Present your answer as a table.
  54. Describe5 marksChallengeDescribe the sequence of events that leads to the rapid closure of a Venus fly trap leaf when a trigger hair is stimulated twice within a short time period.
  55. Explain6 marksChallengeA student investigates the effect of auxin (IAA) on the pH of the cell wall (apoplast) of stem segments from a plant. The student measures the pH of the apoplast and the elongation of the segments over time after…
  56. Describe5 marksChallengeDescribe the features of the refractory period that limit the maximum frequency of nerve impulses.
  57. Describe5 marksChallengeA student is investigating the effect of myelination on the speed of nerve impulse conduction using two types of neurones isolated from a frog: one sensory neurone that is myelinated and one that is unmyelinated. Both…
  58. Explain6 marksChallengeA student examines a stained longitudinal section of skeletal muscle under a light microscope. The sarcomeres show distinct A-bands, I-bands, and H-zones. The muscle was fixed immediately after electrical stimulation…