BiologyCore16 min read

Biotechnology

Using living organisms and their processes — from fermentation to genetic engineering

This topic appears in:

10th Class Biology · ch.172nd Year Biology · ch.23

Practise the full question bank:

10th Class Biology — MCQs & exam Qs2nd Year Biology — MCQs & exam Qs
01

Using living things

Biotechnology is the use of living organisms, or their processes, to make useful products. It is ancient — bread, cheese, yoghurt and alcohol all rely on microbes — and modern, from antibiotics grown in giant vats to crops improved by altering their genes. Microorganisms are ideal workers: they grow fast, need cheap food, and can be grown anywhere in controlled conditions.

02

Fermentation

In fermentation, microorganisms respire (often anaerobically) on a food source to make a useful product. Yeast ferments sugars to ethanol and carbon dioxide — the ethanol makes beer and wine, and the carbon dioxide makes bread rise. Bacteria ferment the sugar in milk to lactic acid, turning it into yoghurt and cheese. Antibiotics such as penicillin are also made by growing microbes in large fermenters under carefully controlled conditions.

MicrobeProductUse
Yeastethanol + CO₂brewing, bread-making
Bacteria (Lactobacillus)lactic acidyoghurt, cheese
Fungi/bacteriaantibioticstreating infection
03

Genetic engineering

Genetic engineering transfers a gene from one organism into another, so the new organism makes a useful protein. A gene (for example the human insulin gene) is cut out with enzymes, inserted into a bacterium's DNA, and the bacterium is grown in huge numbers — each copy now producing insulin cheaply and reliably for people with diabetes. The same technology gives crops resistance to pests or disease.

04

Benefits and concerns

Biotechnology brings clear benefits — cheap medicines, higher crop yields, and useful materials — but also raises concerns about safety, ethics and unintended effects on ecosystems, so its uses are regulated. Weighing benefits against risks is part of using it responsibly.

Why bacteria make our insulin

Insert the human insulin gene into a bacterium and it becomes a tiny factory. Grown by the billion, the bacteria make pure human insulin cheaply — far better than extracting it from animals.

05

A worked example

Worked example

Explain how genetically engineered bacteria are used to make human insulin.

  1. The human insulin gene is cut out of human DNA using enzymes.Enzymes cut DNA at specific points.
  2. The gene is inserted into the DNA of a bacterium.The bacterium now carries the instruction to make insulin.
  3. The bacteria are grown in large numbers in a fermenter.Each copy makes insulin, so many bacteria make a lot.
  4. The insulin they produce is collected and purified.It is then used to treat diabetes.

The insulin gene is transferred into bacteria, which are grown in bulk to produce pure human insulin cheaply for treating diabetes.

06

Inside an industrial fermenter

Growing microbes on a large scale — for antibiotics, enzymes or single-cell protein — is done in a fermenter, a large vessel where conditions are carefully controlled to keep the microbes productive. The temperature is kept optimal (cooling water removes the heat of respiration), the pH is monitored and adjusted, oxygen and nutrients are supplied, the mixture is stirred to keep it even, and everything is kept sterile to stop unwanted microbes competing or contaminating the product.

Condition controlledWhy
Temperaturekeep enzymes at their optimum; remove excess heat
pHkeep the microbe's enzymes working
Oxygen and nutrientssupply what the microbes need to grow
Sterilitystop contamination by other microbes
07

GM crops and cloning

Beyond microbes, biotechnology reshapes whole organisms. Genetically modified (GM) crops carry inserted genes for useful traits — resistance to pests or herbicides, higher yield, or added nutrients (like vitamin-enriched rice). Cloning produces genetically identical organisms: plants are cloned quickly by tissue culture, and animals by techniques such as transferring a body-cell nucleus into an egg. These raise real benefits (food security, medicines) alongside safety and ethical debates.

Practice questions

5 questions · 19 marks · full working on every one

Try each one on paper first, then open the working. The marks are shown where they are actually awarded, because that is where they are actually lost.

Short questions

3 · 8 marks

Two marks each, in the style of the short-question section of the paper. Answer in two or three lines.

SQ1[2 marks]
Explain the role of yeast in both brewing and bread-making.
Model answer

Yeast ferments sugars, producing ethanol and carbon dioxide. In brewing the ethanol makes the alcoholic drink; in bread-making the carbon dioxide is trapped in the dough and makes it rise.

Examiner tip. Same reaction, different useful product — ethanol vs CO₂.

SQ2[3 marks]
Give one benefit and one concern of genetic engineering, and one product it makes.
Model answer

Benefit: it produces cheap, pure medicines such as human insulin (or pest-resistant crops). Concern: possible safety, ethical or ecological risks. Product: human insulin.

Examiner tip. Balance a benefit against a concern, and name a real product.

SQ3[3 marks]
State three conditions that must be controlled in an industrial fermenter and why each matters.
Model answer

Temperature — kept at the optimum for the microbe's enzymes (and cooled to remove respiration heat); pH — kept optimal so the enzymes work; sterility — to stop contamination by unwanted microbes. (Oxygen/nutrient supply and stirring are also valid.)

Examiner tip. Give the condition AND the reason for each.

Long questions

2 · 11 marks

Theory and numerical together, as they appear in the long-question section.

LQ1[6 marks]
Human insulin for treating diabetes is made using genetically engineered bacteria.
  1. Describe the steps used to make the bacteria produce insulin. [4]
  2. State two advantages of this method over extracting insulin from animals. [2]
Mark scheme
  1. The human insulin gene is cut out of human DNA using enzymes[1]
  2. it is inserted into the DNA of a bacterium[1]
  3. the bacteria are grown in large numbers in a fermenter[1]
  4. the insulin they make is collected and purified[1]
  5. It produces pure human insulin (fewer allergic reactions)[1]
  6. in large amounts, cheaply and reliably[1]

Cut out the insulin gene, insert it into bacteria, grow them in a fermenter, purify the insulin; advantages: pure human insulin, cheap and plentiful.

Examiner tip. Describe the gene transfer and growth, then compare with animal insulin.

LQ2[5 marks]
Biotechnology is used to modify and clone organisms.
  1. Explain what a genetically modified crop is and give one benefit. [3]
  2. State one benefit and one concern of GM technology. [2]
Mark scheme
  1. A GM crop has had a gene from another organism inserted into its DNA[1]
  2. so it gains a useful characteristic[1]
  3. e.g. resistance to pests, higher yield or added nutrients[1]
  4. Benefit: more or better food / medicines produced[1]
  5. Concern: possible effects on health or ecosystems, or ethical objections[1]

A GM crop carries an inserted gene for a useful trait (e.g. pest resistance); benefit = better food/yield, concern = health/ecological/ethical risks.

Examiner tip. Define GM, give a concrete benefit, then balance a benefit against a concern.