Using plant genetic information
A genome is the complete set of genes of a living thing. Scientists can now read the whole genome of rice, wheat, maize and many other plants. This makes it easier to find which genes give which traits.
- DNA markers are short, known pieces of DNA near a useful gene. Breeders test a seedling's DNA early, instead of waiting for the full-grown plant. This is called marker-assisted breeding.
- Genetic engineering moves a gene from one organism to another (for example the Bt gene that makes a protein toxic to some insects).
- Genome editing (for example CRISPR) changes a few letters at an exact spot in the plant's own DNA.
- Goals: more yield, drought and salt tolerance, pest and disease resistance, extra nutrition (vitamin A, iron), longer shelf life.
Good practice: test safety, label the product, protect nature and farmers, and listen to public worries. Rules differ between countries.
Using biomass energy
Biomass is any plant or animal material that can be used for energy: crop straw, husk, wood chips, bagasse (what is left after pressing sugarcane), cow dung and food waste.
- Biogas: microbes without air break down wet waste in a closed tank and give methane gas for cooking or electricity.
- Bioethanol: yeast ferments sugar or starch (sugarcane, maize) into alcohol, which is mixed with petrol.
- Biodiesel: oils from plants (such as jatropha, palm, used cooking oil) are chemically changed into a diesel-like fuel.
- Direct burning or pellets: dry waste is pressed and burnt in boilers.
Why it is called renewable: the carbon dioxide released was taken in by the plants not long ago, so over a full cycle it can be nearly balanced. It is not automatic: land use, fertiliser and transport also matter. Growing fuel on land needed for food can raise food prices, so waste and non-food crops are preferred.
Trends in biotechnology in industry
- Food and farming: faster breeding, disease-free planting material from tissue culture, indoor vertical farms.
- Medicines: plants and plant cells grown in tanks to make vaccines, antibodies and medicines (for example a cancer drug first found in a yew tree can now be made from cell cultures).
- Materials: bioplastics from starch or sugar, plant fibres, natural dyes.
- Green chemistry: enzymes replace harsh chemicals in making paper, detergents and textiles.
- Data and AI: computers study huge gene and field-data sets to choose the best crops.
Key questions for every new product: Is it safe for people and nature? Is it fair to farmers and communities? Does it really cut waste and carbon? Careers include plant breeder, lab technician, bioprocess engineer and regulatory scientist.
Try it: a trade-off table
Choose a crop (say, rice). On paper, make three columns: Benefit, Risk, Who decides. Fill them for a drought-tolerant rice, for rice-straw biogas and for a bioplastic made from rice starch. You will see that every technology has a gain and a question to be answered. This is how experts think too.
Key formulas and definitions
- Key term: Genome = complete set of genes of an organism
- Key term: Biomass = plant or animal material used for energy
- Key term: Biofuel = fuel made from biomass (biogas, bioethanol, biodiesel)
- Key term: Genome editing = changing exact letters in an organism's own DNA
- Idea: Renewable = the carbon released was recently taken in by plants
- Biogas is mainly methane (CH4)
Worked examples
1. A farm has 10 tonnes of rice straw. If 1 tonne of straw gives 300 m³ of biogas, how much biogas is possible?
10 × 300 = 3,000 m³ of biogas (a simple, rounded example).
2. A breeder tests seedlings with a DNA marker for a disease-resistance gene. 40 of 200 seedlings carry the gene. What percentage carry it, and why test seedlings?
40 / 200 × 100 = 20%. Testing seedlings saves time and field space because only the 20% need to be grown to full size.
3. A petrol blend is 10% ethanol. How much ethanol is in 50 litres of the blend?
10% of 50 = 0.10 × 50 = 5 litres of ethanol.
4. Give one benefit and one risk of growing a fuel crop on farmland.
Benefit: a renewable fuel and income for farmers. Risk: land and water are used that could grow food, which can raise food prices.
Common mistakes
- Thinking "biofuel is always carbon-free". Growing, fertiliser and transport also release carbon.
- Mixing up genetic engineering (adds a gene, often from another species) with genome editing (changes letters in the plant's own gene).
- Believing a trait gene works the same in every crop and place. Environment also matters.
- Forgetting that safety checks, labelling and public trust are part of biotechnology.