Survival and Response: AQA A Level Biology Exam Questions by Topic

AQASurvival and ResponseExam Questions
Written by Tom Whitburn

Survival and response (AQA 3.6.1.1) is the first section of Year 13 topic 6, and it's A-level only. You need to explain how responding to changes in the environment helps organisms survive, how growth factors such as IAA move from growing regions and control cell elongation in shoots and roots, how this explains phototropism and gravitropism, and how taxes and kineses keep a mobile organism in favourable conditions. The simple three-neurone reflex is in this section too.

The examiners' reports keep finding the same slips. Students say the shoot tip 'contains' IAA instead of producing it, write 'more growth' instead of cell elongation, and describe phototropism when there's no directional light at all. On animal behaviour they call a directional response a kinesis or a tropism, give 'to survive' as the advantage, and describe the data when the question wants a conclusion or an evaluation.

Start with the IAA questions, then taxes and kineses, and finish with the practical and calculation questions. Write your answer on paper before you open each mark scheme. If you'd like help with this topic, my AQA masterclasses run online on Tuesdays at 5.15pm for Year 12 and on Wednesdays or Thursdays at 6.30pm for Year 13.

What you need from GCSE and Year 12

Each question on this page assumes you're secure on these GCSE and Year 12 ideas. If any of them feels shaky, revise it before you start.

  • GCSE: plant shoots grow towards light (positive phototropism) and roots grow towards gravity (positive gravitropism), controlled by auxin, which is unequally distributed in the shoot or root.
  • GCSE: a reflex arc runs from receptor to sensory neurone, relay neurone, motor neurone and effector, and reflexes are rapid and automatic.
  • Year 12 (AQA 3.2.2): plant cells divide by mitosis in growing regions such as shoot and root tips.
  • Year 12 (AQA 3.4.4): adaptations that increase an organism's chance of survival and reproduction are favoured by natural selection.
  • Year 12 (AQA 3.4.7 and the statistics skills): a null hypothesis says there is no difference, and P less than 0.05 means the probability that the difference is due to chance is less than 5%.

Key terms

These words come up in the questions and mark schemes. Examiners expect you to use them exactly.

  • Growth factor: a specific chemical that moves from growing regions to other tissues, where it regulates growth in response to directional stimuli.
  • Indoleacetic acid (IAA): a growth factor produced in shoot tips; accept auxin. Say the tip produces it, not that it contains or stores it.
  • Cell elongation: IAA increases cell wall plasticity so the cells stretch and get longer; 'more growth' on its own doesn't score.
  • Phototropism: a growth response to directional light; IAA moves to the shaded side of a shoot, so cells there elongate more and the shoot bends towards light.
  • Gravitropism: a growth response to gravity; IAA collects on the lower side, where it stimulates elongation in shoots but inhibits it in roots.
  • Roots and IAA: high IAA concentrations inhibit cell elongation in roots, the opposite of its effect in shoots.
  • Taxis: a simple directional response: the organism moves towards (positive) or away from (negative) a stimulus, for example negative phototaxis.
  • Kinesis: a simple non-directional response: the organism changes its speed of movement or rate of turning in unfavourable conditions.
  • Simple reflex: a rapid, automatic, protective response through three neurones: sensory, relay and motor.
  • Choice chamber: a container divided into areas with different conditions, such as light intensity, used to see which conditions an animal moves to.

What these questions cover (AQA 3.6.1.1)

The questions test these statements from the AQA AS and A-level Biology specification (7401/7402):

  • Survival and response: Organisms increase their chance of survival by responding to changes in their environment. (the chilling seeds question asks how a response to the seasons helps a plant survive)
  • Plant growth factors: In flowering plants, specific growth factors move from growing regions to other tissues, where they regulate growth in response to directional stimuli.
  • IAA and tropisms: The effect of different concentrations of indoleacetic acid (IAA) on cell elongation in the roots and shoots of flowering plants as an explanation of gravitropism and phototropism in flowering plants.
  • Taxes and kineses: Taxes and kineses as simple responses that can maintain a mobile organism in a favourable environment.
  • Simple reflexes: The protective effect of a simple reflex, exemplified by a three-neurone simple reflex. (no written question on the three-neurone reflex was available for this page, so learn the receptor, sensory, relay and motor neurone pathway from your notes)
  • Practical work: Required practical 10: Investigation into the effect of an environmental variable on the movement of an animal using either a choice chamber or a maze. (the choice chamber questions here are about taxes; required practical 10 will have its own page)

How to use this page

Write your answer on paper before you open the mark scheme. Allow about 1.3 minutes per mark: the 14 questions are worth 39 marks, so about 51 minutes in total. Then mark your answer strictly against the mark scheme and read the examiners' tip underneath it. If you'd rather print the questions, download the PDF pack.

IAA and plant growth (3.6.1.1)

Question 1

A level Paper 2 · June 2019 · Q03.1 · 2 marks · Easy

Explain why the shoot tip was removed before testing IAA on oat shoots.

Method: 10 mm lengths of oat shoot with the tips removed were left in five concentrations of IAA with glucose, in the dark at 20 °C for 5 days. Table 1: mean change in length rises from 0.0 mm at 10⁻⁵ ppm to 3.1 mm at 10 ppm IAA. Question asks why the student removed the shoot tip from each seedling, 2 marks.
Show the mark scheme Mark scheme, in pairs: the tip produces IAA, so it would affect the IAA concentration or the shoot length; or mitosis occurs in shoot tips, so it would affect growth or elongation. Ignore 'contains' or 'stores' IAA.

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From the examiners' report: Almost 80% got a mark, usually for 'the tip produces IAA'. 'Contains IAA' didn't score. Then say why it matters: it would change the IAA concentration and so the growth.

Question 2

A level Paper 2 · June 2019 · Q03.4 · 3 marks · Medium

Describe and explain the IAA results for shoots and predict the results for roots.

Table 1: IAA concentration from 10⁻⁵ to 10 parts per million against mean change in length of oat shoot, 0.0, 0.1, 1.3, 2.4 and 3.1 mm. Question asks you to describe and explain the results and suggest how they would differ with lengths of root, 3 marks.
Show the mark scheme Mark scheme: the higher the IAA concentration, the greater the mean change in length; IAA stimulates cell elongation; in roots growth or elongation would be less or inhibited. Reject 'decreases length' on its own.

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From the examiners' report: About 20% got all three. Say 'mean change in length' and 'IAA concentration' when you describe, name cell elongation, and say root growth is inhibited rather than that roots get shorter.

Question 3

A level Paper 2 · November 2021 · Q03.1 · 3 marks · Hard

Use IAA to explain why a shoot bends when its tip is replaced on one side.

Figure 1: a shoot tip is removed, then replaced on one side of the cut shoot, and growth curvature occurs without a directional light source. Question asks you to use your knowledge of IAA to explain the growth curvature, 3 marks.
Show the mark scheme Mark scheme: the tip produces IAA; IAA diffuses into or down the shoot; more elongation of cells on one side than the other. Reject any reference to the shaded side or light.

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From the examiners' report: Only 7% got all three. There's no directional light, so don't describe phototropism. The tip produces IAA, it diffuses down, and cells elongate more on that side; 'more growth' didn't score.

Question 4

A level Paper 2 · November 2021 · Q03.3 · 2 marks · Hard

State two conclusions about IAA from a bioassay of shoot tips kept in the dark or light.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Figure 4: shoot tips on agar blocks, left in the dark (1), lit from one side (2), or lit from one side with an impermeable barrier splitting the block into A and B (3). Table 1: bioassay curvature 17.69°, 17.61°, 11.22° (3A) and 6.50° (3B). Question asks for two conclusions about IAA, 2 marks.
Show the mark scheme Mark scheme: IAA is not broken down by light, or is produced in the dark, or light doesn't affect its production; IAA moves away from light or to the shaded side. 'Accumulates on the shaded side' needs the idea of movement.

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From the examiners' report: Only 1% got both marks. Don't describe the numbers: compare 1 with 2 to conclude about production, and 3A with 3B to conclude that IAA moves away from light.

Question 5

A level Paper 2 · June 2024 · Q08.1 · 2 marks · Medium

Explain the link between IAA concentration, cell wall plasticity and growth of stem segments.

Figure 6: line graph with two y-axes; cell wall plasticity (dashed, about 1.6 to 7 arbitrary units) and mean growth of stem (solid, about 0.6 to 4 mm) both rise as IAA concentration increases from 10⁻⁸ to 10⁻⁵ mol dm⁻³. Question asks you to explain the relationship, 2 marks.
Show the mark scheme Mark scheme: increasing IAA concentration increases cell wall plasticity, or IAA activates enzymes that increase plasticity; the increase in plasticity results in cell elongation. 'IAA causes cell elongation' on its own isn't enough.

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From the examiners' report: Only about 17% got both. Read the negative indices carefully: 10⁻⁵ is higher than 10⁻⁸. Then link plasticity to cell elongation instead of just saying IAA causes elongation.

Taxes, kineses and survival (3.6.1.1)

Question 6

A level Paper 3 · November 2021 · Q03.1 · 2 marks · Medium

Name the behaviour of beetles walking towards a light and suggest one advantage.

Figure 2: oval sample area with a single light source at the top and decreasing light intensity downwards; the walking paths of four beetles, G, J, P and R, all go from the release point to the light. Question asks you to name the behaviour and suggest one advantage, 2 marks.
Show the mark scheme Mark scheme: (positive photo) taxis; any suitable advantage, for example to avoid competition, to find a mate, to increase dispersal or to avoid predators. Reject negative taxis.

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From the examiners' report: Only 18.56% got both. It's a taxis, not a tropism or a kinesis, and the beetles move towards the light. Give a specific advantage; 'to survive' is too vague.

Question 7

A level Paper 3 · November 2021 · Q03.2 · 3 marks · Hard

Suggest why conclusions about beetle movement between 35 °C and 37.5 °C may not be valid.

Figure 3: percentage of beetles on the light side (solid line, about 65% falling to 39%) and mean speed of movement (dashed line, rising from about 31 to 39 cm min⁻¹, plotted only up to 35 °C) against temperature from 25 to 40 °C. Question gives three conclusions and asks why they might not be valid, 3 marks.
Show the mark scheme Mark scheme, max 3: no statistical test, so no evidence of a significant change; between 35 and 36.5 °C more than half are still on the light side; beetles may be flying, not walking; slowing starts before 35 °C; slowing may be preparation to fly; speed not recorded above 35 °C; a mean hides beetles that are fast or still.

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From the examiners' report: Only 4.47% got even 2 marks. Explain why the conclusions are not valid, using the figure. The stem says many beetles were used, so 'small sample size' and 'other factors' don't score.

Question 8

A level Paper 2 · June 2025 · Q07.2 · 2 marks · Medium

Name the behaviour of freshwater shrimps in a choice chamber and suggest an advantage.

Table 3: number of G. pulex (freshwater shrimps) in each choice chamber segment after 10 minutes; A 0% light 15, B 25% light 8, C 50% light 4, D 100% light 3. Question: the student observed directional movement; name the type of behaviour and suggest an advantage, 2 marks.
Show the mark scheme Mark scheme: (negative photo) taxis; predation less likely, less visible to predators, move away from heat or move towards food.

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From the examiners' report: About 40% got both. Directional movement is a taxis, not a kinesis or phototropism, and the shrimps move away from light. Link the advantage to predators; 'to survive' is too general.

Question 9

A level Paper 3 · June 2019 · Q05.3 · 3 marks · Medium

Evaluate whether flashing or constant light could move crown-of-thorns starfish away from reefs.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Table 1: crown-of-thorns starfish (COTS) in a choice chamber; flashing light 22 towards and 28 away, P = 0.69; constant light 12 towards and 38 away, P = 0.02. Question: a journalist suggested either type of light could be used to move COTS away from coral reefs; evaluate this, 3 marks.
Show the mark scheme Mark scheme: yes, movement is away from both types of light (negative phototaxis); significant movement away from constant light as P = 0.02, less than 0.05; no, movement away from flashing light is not significant as P = 0.69, more than 0.05, so it may be due to chance.

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From the examiners' report: Only about 6% got all three. Give both sides: both lights cause movement away, but only constant light gives a significant result. Use P against 0.05, not 'results are significant'.

Question 10

AS Paper 2 · June 2016 · Q05.4 · 3 marks · Hard

Suggest how a chilling requirement helps seeds survive seasonal changes.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Figure 6: mean mass of phosphate in embryos of cherry seeds over 16 weeks, rising from 2 to about 7.8 g × 10⁻⁸ at 5 °C but falling to about 1.3 at 25 °C. Question: the chilling requirement is an adaptation for survival with seasonal changes; suggest how it helps the plants survive and respond, 3 marks.
Show the mark scheme Mark scheme, max 3: seeds stay dormant, or the embryo develops, in winter; seeds or plants develop in spring or summer when temperature or light increases; plants photosynthesise in spring; produce more seeds in the growing season. Reject plants germinating in winter.

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From the examiners' report: Almost 60% scored zero. The plants don't grow in winter: the seed stays dormant until it's warmer, then germinates and photosynthesises in spring. Don't turn it into a natural selection answer.

Practical and maths skills (3.6.1.1)

Question 11

A level Paper 2 · November 2021 · Q03.2 · 5 marks · Medium

Describe how to use a curvature bioassay to compare IAA in shoot tips from two species.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Figure 2: shoot tips placed on agar, removed, the agar cut into blocks, a block placed on one side of a cut shoot, then the shoot kept in the dark and the degree of curvature measured. Figure 3: calibration curve of degree of curvature (0 to 20) against IAA concentration in agar block (0 to 0.25 mg dm⁻³). Question asks how to compare IAA in two species, with the control variables, 5 marks.
Show the mark scheme Mark scheme, max 5 (max 3 variables): size of tip; number of tips; size or type of agar block; shoots at the same stage of growth; time; temperature; repeat and calculate a mean; read the degree of curvature on the calibration curve to find the IAA concentration.

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From the examiners' report: Half got at least three marks, but only 3% got all five. After three control variables, add repeats with a mean and how you read the curvature off the calibration curve; don't add known IAA concentrations to the agar.

Question 12

A level Paper 2 · June 2024 · Q08.2 · 2 marks · Hard

Calculate the percentage increase in stem growth from the IAA graph.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Figure 6: cell wall plasticity (dashed) and mean growth of stem (solid, right-hand axis 0 to 4 mm) against IAA concentration from 10⁻⁸ to 10⁻⁵ mol dm⁻³. Question asks for the percentage increase in mean growth from 10⁻⁸ to 10⁻⁵ mol dm⁻³ to 2 significant figures, 2 marks.
Show the mark scheme Mark scheme: 570% for 2 marks; 1 mark for 560, 566 or 567%, or for some wrong readings. Using the plasticity values loses a mark.

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From the examiners' report: About 26% got 570%. Use the growth axis on the right, not plasticity, and round to 2 significant figures: 566.7% scores only 1 mark.

Question 13

A level Paper 2 · June 2024 · Q08.4 · 5 marks · Medium

Describe a procedure to test the effect of GA concentration on growth of stem segments.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Question text: gibberellic acid (GA) is another plant growth factor; a student has five GA concentrations from 10⁻¹ to 10⁻⁵ mol dm⁻³, distilled water, 6 Petri dishes and 60 stem segments of different lengths. Question asks for a suitable procedure including control variables, 5 marks.
Show the mark scheme Mark scheme, max 5 (max 3 control variables): distilled water control and each GA concentration with 10 segments each; measure length at start and end or find the change in length; same volume of solution; same time; same temperature; same species; same age; same diameter of segments.

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From the examiners' report: About 12% got all five. Use all 60 segments with a water control, and measure the length at the start and the end. 'Amount' of GA didn't score, and light, pH and CO2 were ignored.

Question 14

A level Paper 3 · June 2019 · Q05.4 · 2 marks · Medium

Calculate the time for a starfish to move 48 m up a reef in daylight.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Table 2: maximum speed of COTS moving towards constant light 259 mm min⁻¹ and away from it 564 mm min⁻¹. Question asks for the shortest time for one COTS to move up a reef from 66 m to 18 m under water in daylight, to the nearest hour, 2 marks.
Show the mark scheme Mark scheme: 3 hours for 2 marks; 1 mark for 48 000 mm in working, or for 185 minutes or 3.09 hours; 1 max for 1 hour, which uses 564.

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From the examiners' report: Just over a third got both. Moving up the reef is towards the light, so use 259 mm min⁻¹. Convert 48 m to 48 000 mm, not 4800, and give the answer to the nearest hour.

Where students lose marks (from AQA examiners' reports and mark schemes)

Each point below is followed by wording that gained marks.

  • The tip produces IAA; it doesn't just contain it: Almost 80% got a mark for saying the shoot tip produces IAA, but a significant number simply said the tip contained IAA, which wasn't credited. On the growth curvature question the same slip cost marks again.

    ✔ Gains credit: "Tip produces IAA" and "affects (shoot) length, growth or elongation".

  • Name cell elongation, not 'more growth': Only the more effective responses referred specifically to cell elongation. On the curvature question, 'more growth' or 'more elongation' wasn't credited, and on cell wall plasticity many said IAA caused elongation without saying how.

    ✔ Gains credit: "(More) elongation of cells on one side (than the other)"; "increase in cell wall plasticity results in cell elongation".

  • No directional light, so it isn't phototropism: Figure 1 showed curvature without a directional light source, yet many described phototropism or wrote about the shaded side. IAA diffusing into the shoot was rarely credited, so only 7% got all three marks.

    ✔ Gains credit: "Tip produces IAA; IAA diffuses (into the shoot); (more) elongation of cells on one side."

  • In roots, IAA inhibits elongation: Many knew high IAA has a different effect on roots, but 'the length of roots would decrease' wasn't credited. Some only described the roots and never described the shoot results.

    ✔ Gains credit: "In roots, growth or elongation is less or inhibited"; accept a decrease in (mean) change in length.

  • Conclude about IAA, don't redescribe the table: Only 1% got both marks for two conclusions about IAA from the bioassay. Most simply described the results in Table 1, or wrote about bending instead of the movement or production of IAA.

    ✔ Gains credit: "IAA is not broken down by light (or is produced in the dark)"; "IAA moves away from light, to the shaded side".

  • Directional movement is a taxis: Only 18.56% got both marks for the pine beetles; 'tropism' and 'kinesis' were common wrong answers. On the freshwater shrimps, the most frequent errors were 'kinesis', 'phototropism' and 'positive phototaxis'.

    ✔ Gains credit: "(Positive photo) taxis" for beetles walking towards light; "(negative photo) taxis" for shrimps moving away from it.

  • Give an advantage, not 'to survive': Vague answers such as 'to survive' or 'to obtain more favourable conditions' didn't score, and some said the animals moved towards light 'for photosynthesis'.

    ✔ Gains credit: "Predation less likely" or "less visible to predators"; for beetles "to find a mate, increase dispersal or avoid competition".

  • Dormant in winter, growing in spring: Almost 60% scored zero on the chilling requirement of seeds. The commonest misconception was that the plants grow during the winter so they are fully grown by spring.

    ✔ Gains credit: "Seeds remain dormant in winter; seeds or plants develop in spring or summer when temperature or light increases; plants photosynthesise in spring."

Download the questions

Download the PDF pack (14 questions, mark schemes at the end)

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Questions, mark schemes and examiners' report extracts © AQA.

Tom Whitburn
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