OxfordAQA International GCSE Biology: Genetic manipulation: cloning and GM crops (9201) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover section 3.5.5 (Genetic manipulation, parts a to f) of the OxfordAQA International GCSE Biology (9201) specification, Version 5.2, for exams May/June 2018 onwards. The qualification is untiered. Start with the study guide or the revision notes. Course pages: OxfordAQA IGCSE Biology and the checklist. Find weak areas with the free diagnostics.

Questions

1. (a) State what is meant by a clone. [1] (b) A gardener makes new geranium plants by cuttings. Give two features of this method. [2]

2. A farmer wants a new calf that is genetically identical to her best dairy cow, using a cell taken from the cow’s skin. Describe the stages by which this calf could be produced. [5]

3. A breeder splits the cells of a young cattle embryo and transplants the resulting embryos into host cows. (a) Explain why the cells must be split before they become specialised. [2] (b) Explain why two calves that grew from cells of the same original embryo are genetically identical. [1] (c) State how the genes of a calf compare with those of its host mother. [1]

4. An orchid nursery uses tissue culture. One small group of cells is divided into 5 pieces. After each growth period every group is again divided into 5 pieces. This happens 4 times. (a) Calculate the number of groups of cells after the fourth division. [2] (b) The cells are grown on a sterile nutrient medium. Explain why it must be sterile. [2]

5. A farm collects 15 embryos from 3 donor cows. Each is split into 2 and the 30 embryos are transplanted into host cows. 18 calves are born alive. (a) Calculate the percentage of transplanted embryos that gave a live calf. [2] (b) Suggest one reason why not every transplanted embryo gave a calf. [1] (c) The farmer says that all 18 calves are identical to each other. Evaluate this statement. [2] (d) Suggest one disadvantage of a herd made from only a few sets of identical calves. [1]

6. Describe how a human gene can be transferred into bacteria so that they make the protein it codes for. [6]

7. A scientist mixes 8000 bacteria with plasmids that carry a human gene. 56 bacteria take up a plasmid. (a) Calculate the percentage of bacteria that took up a plasmid. [2] (b) A bacterium with the plasmid divides every 15 minutes. Calculate how many bacteria it produces in 2 hours, assuming none die. [2] (c) Explain why this is useful for producing a protein. [1]

8. (a) Explain why genes are transferred into a plant at an early stage of its development, not into a fully grown plant. [2] (b) Name the two types of vector that are usually used. [1]

9. The table shows the yield of a herbicide-resistant GM oilseed rape and a non-GM variety grown in five fields, in tonnes per hectare.

Field	1	2	3	4	5
GM	3.9	4.2	4.0	4.3	4.1
Non-GM	3.4	3.6	3.3	3.5	3.7

(a) Calculate the mean yield of each variety. [2] (b) Calculate, to 3 significant figures, the percentage increase in yield for the GM variety. [2] (c) Suggest two reasons why a herbicide-resistant crop may give a higher yield. [2] (d) Suggest one way to make the conclusion more reliable. [1]

10. Explain two concerns that people have about growing GM crops. [4]

11. A farm trial compared an insect-resistant GM crop with a non-GM crop.

	Non-GM	GM
Insecticide sprays per season	7	2
Yield in tonnes per hectare	18.0	21.0
Wild flower species at the field edge	14	13

(a) Calculate, to 3 significant figures, the percentage increase in yield. [2] (b) Calculate, to 3 significant figures, the percentage reduction in sprays. [2] (c) A neighbouring farmer asks whether he should grow the GM crop. Use the data and your knowledge to make a judgement. [4]

12. A laboratory used adult cell cloning on a farm animal. 150 egg cells received a nucleus from an adult body cell. 24 developed into embryos, 6 pregnancies began and 2 animals were born alive. (a) Calculate the percentage of egg cells that developed into embryos. [1] (b) Calculate the number of egg cells used for each live animal. [1] (c) Calculate the percentage of pregnancies that ended in a live birth. [1] (d) State two differences between how offspring are produced by adult cell cloning and by embryo transplants. [2] (e) Suggest two reasons why a breeder might still use adult cell cloning, despite the low success rate. [2]

Answers

1. (a) An organism that is genetically identical to its parent [1] (b) Any two of (1 mark each, maximum 2): needs no special equipment; produces many identical plants from one parent; an older, simple method used by gardeners; no seeds or fertilisation needed [2] [3] Examiner insight: “Quick” or “cheap” on their own are weak. Tie the feature to the method, such as “no special equipment needed”.

2. The nucleus is taken out of an unfertilised egg cell from another cow [1]; a nucleus taken from an adult body cell, for example a skin cell, is put into that egg cell [1]; an electric shock acts as the catalyst, so the egg cell begins to divide [1]; giving embryo cells with the same genetic information as the adult cell [1]; at the ball-of-cells stage the embryo is placed in the womb of an adult female, where it continues to develop [1] [5] Examiner insight: Say which cell each nucleus comes from. “DNA from the adult” is less precise about what is removed and inserted.

3. (a) Before they are specialised, each cell can still develop into a whole animal [1]; after specialisation the separated cells could no longer grow into a complete calf [1] (b) They came from the same embryo, so they have the same genetic information [1] (c) There is no genetic link, because the host mother only carries the embryo [1] [4] Examiner insight: In part (c) say genes, and say what the host does.

4. (a) 5 × 5 × 5 × 5 [1] = 625 groups [1] (b) Bacteria and fungi grow faster than plant cells on a nutrient medium [1]; they would compete with or kill the plant cells [1] [4] Examiner insight: Show the repeated multiplication or the power 5⁴.

5. (a) 18 ÷ 30 × 100 [1] = 60% [1] (b) Any one of: the embryo did not implant in the womb; the embryo failed to develop; a pregnancy was lost [1] (c) Calves from the two halves of the same original embryo are identical to each other [1]; calves from different original embryos are not identical [1] (d) There is little genetic variation, so a single disease could affect the whole herd [1] [6] Examiner insight: “Evaluate” asks for a judgement. Say that the statement is only partly correct and explain which calves are identical.

6. Any six of (1 mark each, maximum 6): enzymes isolate or cut out the required gene from a human chromosome; a plasmid (vector) is taken from a bacterium; the plasmid is cut open using an enzyme; the human gene is inserted into the plasmid; the plasmid is put into bacterial cells; the bacteria divide, making many copies of the gene; the bacteria make the protein coded for by the gene [6] Examiner insight: Keep the steps in order.

7. (a) 56 ÷ 8000 × 100 [1] = 0.7% [1] (b) 2 hours = 120 minutes, 120 ÷ 15 = 8 divisions [1]; 2⁸ = 256 bacteria [1] (c) Many bacteria carry the gene, so a large amount of protein can be made [1] [5] Examiner insight: Show how you found the number of divisions, and convert hours to minutes first.

8. (a) The gene is then present in every cell as the plant grows [1]; the plant develops with the desired characteristic throughout, whereas a gene added to a mature plant would reach only some cells [1] (b) A bacterial plasmid and a virus [1] [3] Examiner insight: Link early transfer to cell division. “It is easier” is too vague to explain anything.

9. (a) GM: 20.5 ÷ 5 = 4.1 [1]; non-GM: 17.5 ÷ 5 = 3.5 t/ha [1] (b) (4.1 − 3.5) ÷ 3.5 × 100 [1] = 17.1% [1] (c) Weeds can be killed without harming the crop [1]; so less competition for light, water and minerals [1] (d) Repeat the trial in more fields, on other soils or over more years [1] [7] Examiner insight: Divide by the original (non-GM) value. Dividing by the final value gives a different percentage.

10. Any two concerns, each with an explanation (2 marks each, maximum 4): the effect on wild flowers, because heavy weedkiller use on a herbicide-resistant crop could kill wild flowers in and around fields; the effect on insects, because fewer weeds and pests mean less food for insects, which affects animals that feed on them; uncertainty about human health, because the effects of eating GM crops are not fully known [4] Examiner insight: Give the effect and what it leads to, not only “it is not natural”.

11. (a) (21.0 − 18.0) ÷ 18.0 × 100 [1] = 16.7% [1] (b) (7 − 2) ÷ 7 × 100 [1] = 71.4% [1] (c) Benefits: yield up by 16.7% and sprays down by 71.4%, so higher income and lower costs [1]; one limit: the wild flower species fell from 14 to 13, so there may be some effect on wild plants [1]; one trial only, so more fields and years are needed, and human health effects are uncertain [1]; a conclusion that follows, for example that the benefit to the farmer is clear but wider effects should be monitored [1] [8] Examiner insight: A judgement needs a decision backed by figures from the table, not only a list of benefits and risks.

12. (a) 24 ÷ 150 × 100 = 16% [1] (b) 150 ÷ 2 = 75 [1] (c) 2 ÷ 6 × 100 = 33% (33.3%) [1] (d) Any two (1 mark each, maximum 2): adult cell cloning uses an egg with its nucleus removed plus a nucleus from an adult body cell; embryo transplants split the cells of an existing embryo; an electric shock is used in adult cell cloning; adult cell cloning copies an adult, whereas embryo transplants give animals identical to each other [2] (e) Any two (1 mark each, maximum 2): it copies an adult animal whose features are already known; it can reproduce a valuable animal; it can copy an animal that has already been genetically engineered [2] [7] Examiner insight: In part (d) state both techniques, so a difference is clear.

Where marks are usually lost

• Saying a clone is “similar” instead of genetically identical.
• Not saying the nucleus is removed from the egg cell in adult cell cloning.
• Saying the electric shock fertilises the egg.
• Forgetting that embryo cells must be split before they become specialised.
• Writing that plasmids come from humans. The plasmid is the bacterial vector.
• Using the final value as the denominator in a percentage change.
• Giving concerns about GM crops with no explanation, or judging without using the figures.

Next steps

• Revise with the revision notes and re-read the study guide.
• Go to the course hub and tick off the checklist.
• Try all the free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

OxfordAQA International GCSE Biology (9201), Version 5.2, for exams May/June 2018 onwards, published by OxfordAQA. These questions cover section 3.5.5 Genetic manipulation, parts a to f.