AQA GCSE Combined Science: Trilogy Biology Paper 2 (Higher), 2018: Question 5

8 marks · Standard Demand difficulty · Extended Answer

Describe how selective breeding could produce the IR8 rice variety and explain why some people agree and others disagree with growing GM rice plants.

Practise this question

Question

The image shows question 05 with a boxed passage explaining that in the 1950s farmers in India could not grow enough rice, that IRRI scientists used a selective breeding programme with 10 000 rice varieties, and that in 1966 they produced IR8, a high-yield rice variety with short stems and large grains. Question 05.1 asks, for 4 marks, students to describe the steps scientists would have taken to produce IR8 by selective breeding, with lined space for an extended written answer. Question 05.2 asks, for 4 marks, students to explain why some people in India agree and some disagree with genetically modified rice plants being grown, again with lined space for an extended written answer.
Question text

05 Read the following.

In the 1950s farmers in India could not grow enough rice to feed the rapidly

increasing population.

At the International Rice Research Institute (IRRI) scientists began a selective

breeding programme with 10 000 different varieties of rice plants.

In 1966 the IRRI produced a new variety called IR8 which gave a yield of up to ten

times the traditional varieties. IR8 has short stems and large rice grains.

IR8 was grown by farmers all over India so people had enough to eat.

05.1 The IR8 variety of rice was produced by selective breeding.

Describe the steps the scientists would have taken to produce IR8

[4 marks]

05.2 The IRRI has now developed several new varieties of genetically modified (GM)

rice plants.

Some people in India agree and some people disagree with GM varieties of rice

being grown.

Explain why.

[4 marks]

Mark scheme

Show the mark scheme The mark scheme is presented in tables for questions 05.1 and 05.2 with columns for question number, answers, extra information, marks, and specification reference. For 05.1, credit is given for selecting parent rice plants with desired traits such as short stems and large grains, cross breeding them, selecting offspring with the best characteristics, and repeating the breeding until the plants breed true or all have the desired characteristics. For 05.2, credit is given for explained reasons in favour of GM rice, such as disease resistance, herbicide resistance, higher yield, or improved nutritional content, and for explained reasons against it, such as gene transfer to wild plants, reduced biodiversity, loss of traditional varieties, possible health concerns, or expense of GM seeds and specific herbicides.

AO /

Question Answers Extra information Mark

Spec. Ref.

05.1 (the scientists)

chose / used (traditional 1 AO2

varieties of) rice plants with 4.6.2.3

short stems and rice plants with

large grains

or

chose rice plants with short

stems and large grains.

(cross) bred the rice plants allow cross pollinated the rice 1 AO1

plants 4.6.2.3

(from the offspring) chose the 1 AO1

plants with best / desired 4.6.2.3

characteristics

or

chose plants with short(est)

stems and big(gest) grains

bred repeatedly until all plants 1 AO1

had desired characteristics 4.6.2.3

or

bred repeatedly until they bred

true

or

bred repeatedly until they

produced IR8

AO /

Spec. Ref.

05.2 each reason must be explained 4 AO3

to gain credit 4.6.2.4

agree (max 3 marks)

• resistance to disease /

pests / pathogens

so higher yield

• resistant to herbicides

so less competition for

(sun)light / water / minerals /

ions (from weeds)

• larger / more grains per plant

or higher yield

so more food for people or

more income for farmers

• better nutritional content

(vitamins / protein / low GI 14

index)

so will improve health allow improved survival in harsh

conditions so can be grown in

wider area

disagree (max 3 marks)

• may affect wild plants (if

genes transfer)

so making them herbicide

resistant

• use of herbicides may

reduce biodiversity

because other plants are

killed

• traditional varieties no longer

grown

so reduction in biodiversity

• may affect health of people

who eat the rice

because not enough

research done yet allow (GM) seeds are expensive

for farmers because they have

to buy new seeds every year

or because farmers have to buy

specific herbicide

if no explanations allow 1 mark

for one agree reason and one

disagree reason

Total 8

How to answer it

Selective breeding and GM rice

What this question tests

You need to explain how selective breeding works and why GM crops are both supported and criticised. For full marks, give clear, linked points: feature → result → benefit or problem.

Question 05.1 — Producing IR8 by selective breeding [4 marks]

Describe the steps the scientists would have taken to produce IR8

✅ Correct answers

  • Choose parent rice plants with the desired characteristics, such as short stems and large grains.
  • Cross-breed the chosen plants, or allow them to be cross-pollinated.
  • From the offspring, select the plants with the best desired features.
  • Repeat breeding over many generations until the plants breed true / all have the desired characteristics / IR8 is produced.

💡 Key knowledge

  • Selectively breeding means choosing parents with useful characteristics.
  • The useful characteristics are controlled by genes.
  • Scientists keep selecting offspring that show the required feature.
  • Over many generations, the trait becomes more common.

🧠 Exam technique

  • To score full marks, include the whole process: choose → breed → select offspring → repeat.
  • Use phrases like breed true or desired characteristics .
  • Marks are for separate steps, so make each step clear.

❌ Common errors

  • Only saying “choose the best plants” without explaining breeding and repetition.
  • Confusing selective breeding with GM.
  • Not mentioning that the process is done repeatedly.
  • Writing vague answers like “make better rice” with no detail.

📐 How the marks are awarded

  1. 1 mark for selecting plants with short stems / large grains.
  2. 1 mark for cross-breeding them.
  3. 1 mark for selecting the best offspring.
  4. 1 mark for repeating until the desired trait is fixed / breed true.

Question 05.2 — Opinions about GM rice [4 marks]

Explain why some people agree and some people disagree with GM varieties of rice being grown

✅ Correct answers: reasons to agree

  • Resistant to disease / pests / pathogens → higher yield.
  • Resistant to herbicides → less competition from weeds for light, water and minerals, so yield increases.
  • Larger or more grains per plant / higher yield → more food for people or more income for farmers.
  • Better nutritional content (for example vitamins / protein / low GI) → improved health.
  • Can survive better in harsh conditions, so can be grown in a wider area.

❌ Correct answers: reasons to disagree

  • Genes may transfer to wild plants, making them herbicide resistant.
  • Using herbicides may reduce biodiversity because other plants are killed.
  • Traditional varieties may stop being grown, reducing biodiversity.
  • There may be concerns about health effects if not enough research has been done.
  • GM seeds may be expensive because farmers may need to buy new seeds each year or buy a specific herbicide too.

💡 Key knowledge

  • This question wants both sides: one side for agreement and one side for disagreement.
  • Each reason must be explained, not just listed.
  • Use the chain: GM feature → effect → why this matters.

🧠 Exam technique

  • Top answers give at least one explained agree reason and one explained disagree reason.
  • The best responses link directly to yield, food supply, biodiversity, health, and cost.
  • You can earn up to 3 marks on one side, so two well-explained points are enough for strong marks.

📐 Mark breakdown for 05.2

  1. 4 marks total.
  2. Max 3 marks for agreement reasons.
  3. Max 3 marks for disagreement reasons.
  4. If you only give one side, you can still gain marks, but to reach full marks you need both agree and disagree explained.

🧠 Example full-mark style answer

Some people agree because GM rice can be made resistant to disease and pests, so more crops survive and the yield increases. It can also be made resistant to herbicides, so weeds are killed but the rice survives, meaning there is less competition for water, minerals and light. Some people disagree because GM rice could reduce biodiversity if wild plants become herbicide resistant or traditional varieties are not grown. There are also concerns that the health effects may not be fully known yet, and the seeds may be expensive for farmers.

❌ Common traps in 05.2

  • Writing “GM is good/bad” with no explanation.
  • Mixing up herbicides and pesticides.
  • Saying “more food” without stating why the crop produces more.
  • Forgetting that a point only gets credit if it is explained.
  • Using vague words like “better” or “worse” with no biological detail.

Quick recall checklist

Selective breeding

  • Choose parents with desired traits
  • Breed them
  • Select best offspring
  • Repeat for many generations

GM crop advantages

  • Higher yield
  • Disease / pest resistance
  • Herbicide resistance
  • Better nutrition

GM crop disadvantages

  • Reduced biodiversity
  • Gene transfer to wild plants
  • Possible health concerns
  • Higher cost for farmers

Topics

Biology · B6: Inheritance, Variation and Evolution · B7: Ecology

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 2 (Higher), 2018. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.