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IB DemystifiedMYP Sciences

Biotechnology and genetic engineering

Millions of people with diabetes inject human insulin made by bacteria. Cotton plants make their own insecticide, and doctors have begun editing genes to treat inherited blood disorders. Biotechnology lets us read, cut and rewrite DNA, and asks us to decide how we should use that power.

Recommended for MYP 5 · eAssessment priority · About 3 lessons · Criteria A, B, C and D

1 Cut out insulin generestriction enzyme2 Cut open a plasmidsame restriction enzyme3 Join gene into plasmidDNA ligase4 Put plasmid intoa bacterium5 Bacteria multiply in a fermenterand make human insulin → purifyplasmid: a small ring of DNAfound in bacteria
Figure 1. Genetic engineering puts a human gene into bacteria, which then make the human protein.
On this page
  1. Learning objectives
  2. Before you start
  3. Key vocabulary
  4. Understanding the ideas
  5. Genetic engineering in steps
  6. Biotechnology in the real world
  7. Worked examples
  8. In the eAssessment
  9. Check your understanding
  10. Practice questions
  11. Investigation
  12. Criterion-linked questions
  13. Challenge questions
  14. Topic check
  15. Review your mistakes
  16. Your progress

Learning objectives

By the end of this topic you should be able to:

  • describe the stages of genetic engineering, including restriction enzymes, ligase and plasmids
  • explain how microorganisms are grown in fermenters to make useful products
  • describe cloning and compare selective breeding with genetic engineering
  • evaluate GM crops using data, including the evolution of resistance
  • analyse fermenter and crop data
  • discuss the ethics of GM crops and gene editing

Before you start

You will use these skills. If any feel shaky, review them first.

  • DNA, genes and inheritance (see DNA, genes and inheritance)
  • natural selection (see Variation, natural selection and evolution)
  • enzymes and microorganisms

Key vocabulary

Genetic engineering
Changing an organism's DNA, often by inserting a gene from another species.
Restriction enzyme
An enzyme that cuts DNA at a specific base sequence, leaving sticky ends.
DNA ligase
An enzyme that joins pieces of DNA together.
Plasmid
A small ring of DNA in bacteria, used as a vector to carry genes.
Clone
An organism genetically identical to its parent.
Fermenter
A vessel for growing microorganisms under controlled conditions.

Understanding the ideas

  1. What is it?

    All living things use the same genetic code, so a gene from one organism can work in another. Genetic engineers cut out a useful gene with a restriction enzyme, insert it into a plasmid with DNA ligase, and put the plasmid into bacteria, which multiply rapidly and make the protein.

  2. Why does it happen?

    Selective breeding and cloning have been used for thousands of years; genetic engineering is newer and more precise. GM crops such as Bt cotton make their own insecticide; golden rice makes beta-carotene. But natural selection still acts: pests can evolve resistance, as pink bollworm did.

  3. How do we know?

    In industry, microorganisms are grown in sterile fermenters where temperature, pH, oxygen and nutrients are controlled for maximum yield. Scientists test GM crops in field trials and monitor them after release.

  4. Why does it matter?

    Biotechnology has produced insulin, vaccines, enzymes and new crops, and gene editing techniques such as CRISPR are beginning to treat inherited disease. It also raises questions about safety, the environment, fairness and what changes to human genes are acceptable.

  5. What does it connect to?

    Biotechnology links to genetics, evolution and enzymes in biology, to medicine and agriculture, and to ethics and law.

Genetic engineering in steps

  1. Cut out the useful gene with a restriction enzyme, leaving sticky ends.
  2. Cut open a plasmid with the same restriction enzyme.
  3. Join the gene into the plasmid with DNA ligase (a recombinant plasmid).
  4. Put the plasmid into a bacterium (the host).
  5. Grow the bacteria in a fermenter; extract and purify the product.

Biotechnology in the real world

Pakistan approved Bt cotton varieties in 2010, and they are now grown on most of the country's cotton land. Hospitals worldwide use insulin made by GM bacteria. Tissue culture is used to produce thousands of disease-free banana and date palm plants.

Worked examples

Example 1: bacterial growth

Bacteria divide every 25 minutes. Starting with 50, how many after 100 minutes?

  1. 100 ÷ 25 = 4 divisions.
  2. 50 × 2⁴ = 50 × 16 = 800 bacteria.

Example 2: evaluating a GM crop

Why might a GM insect-resistant crop become less effective over time?

  1. Pests vary; a few are resistant.
  2. Resistant pests survive and reproduce.
  3. Resistance spreads by natural selection, so the crop protects less.

In the eAssessment

Biotechnology questions combine processes, data and ethics. Expect:

  • Describe genetic engineering, cloning and fermentation in clear steps.
  • Process data from fermenters and crop trials.
  • Explain resistance using natural selection.
  • Discuss GM crops and gene editing, weighing benefits and risks.

Common ways to lose marks: mixing up restriction enzymes and ligase; confusing selective breeding with genetic engineering; saying pests "get used to" toxins; and giving one-sided ethical arguments.

Check your understanding

Quick questions on the ideas above. Try each one before using a hint.

Practice questions

Show

Investigation: extracting DNA from strawberries

Partially guided investigation · about 40 minutes · pairs

Research question
How does the type of fruit (strawberry, banana, kiwi) affect the amount of DNA that can be extracted from 20 g using a simple kitchen method?
Scientific background
Detergent breaks down cell and nuclear membranes, salt helps DNA clump together, and cold ethanol makes DNA come out of solution as white strands. Strawberries have many copies of each chromosome, so they give a lot of DNA.
Hypothesis
Write your own prediction, with a scientific justification.
Variables
Identify your independent, dependent and control variables, and explain how you will control them.
Apparatus
Strawberries, banana, kiwi, balance, zip-lock bags, washing-up liquid, salt, water, coffee filter and funnel, test tubes, ice-cold ethanol, wooden stick.
Method
  1. Mash 20 g of fruit in a bag with 10 cm³ of extraction solution (water, a little detergent and a pinch of salt).
  2. Filter the mixture into a test tube.
  3. Slowly pour ice-cold ethanol down the side to form a layer on top.
  4. Wait 5 minutes, then wind out the white DNA strands with a stick and compare the amount from each fruit.

Safety. Ethanol is highly flammable: keep it away from flames and use it in a well-ventilated room. Wear eye protection and do not eat anything used in the laboratory.

Then evaluate: how could you measure the amount of DNA more precisely than by looking?

Criterion-linked questions

Criterion B: inquiring and designing

Criterion C: processing and evaluating

Criterion D: reflecting on the impacts of science

Challenge questions

Harder problems in unfamiliar contexts. Plan before you calculate.

Topic check

Five questions picked at random from the whole topic. Take a new set whenever you like.

Review your mistakes

Questions you got wrong on this device appear here so you can try them again. Answer one correctly and it leaves the list.

Your progress

Tracked separately for each skill, on this device only.

SkillCorrectStatus

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