OCR GCSE Biology A B6.2 Feeding the Human Race Exam Questions

About OCR GCSE Biology A B6.2 Feeding the Human Race

B6.2 looks at how a growing human population can be fed sustainably. On the OCR Gateway Biology A course it is part of Topic B6 Global challenges, assessed in Paper 2 (Foundation) or Paper 4 (Higher). It covers threats to food security and the biological solutions used to increase food production, from farming techniques to selective breeding and genetic engineering. It draws on photosynthesis and limiting factors from B1.4, inheritance from B5.1 and ecosystems from B4.1. Examiners often ask you to describe the stages of genetic engineering, compare selective breeding and genetic engineering, and evaluate the benefits and risks of GM crops and farming methods.

What you need to know

• Food security Food security means having enough affordable, nutritious food. Threats include an increasing population, changing diets, new pests and pathogens, climate change, conflict and the cost of farming inputs.
• Farming methods Yields can be increased using fertilisers, pesticides, greenhouses and hydroponics, where plants are grown in mineral solutions without soil. Biological control uses a natural predator or parasite to reduce a pest population.
• Selective breeding Humans choose parents with desired characteristics, breed them, and repeat over many generations. It can produce high-yield or disease-resistant crops, but reduces genetic variation and can cause inbreeding.
• Genetic engineering A gene is cut out of one organism using restriction enzymes, inserted into a vector such as a plasmid or virus using ligase, and transferred into the cells of another organism. Organisms that have taken up the gene are selected, for example using antibiotic resistance markers.
• GM crops GM crops can be engineered to resist pests or herbicides, or to contain extra nutrients. Concerns include effects on wild populations, spread of genes to wild plants and long-term health effects.
• Biotechnology in food Microorganisms can be grown in fermenters to produce food such as mycoprotein. Bacteria can also be modified to make useful products such as human insulin.

Common mistakes in B6.2 Feeding the Human Race

• Saying genetic engineering and selective breeding are the same. Selective breeding chooses parents over many generations; genetic engineering directly transfers a gene, often between species.
• Describing biological control without risks. The introduced species can become invasive or feed on non-target species.
• Forgetting to name the enzymes in genetic engineering. Restriction enzymes cut DNA; ligase joins DNA into the vector.
• Writing that hydroponics needs no minerals. The water must contain dissolved mineral ions such as nitrates.
• Claiming GM crops are proven to be harmful. Give balanced concerns, such as uncertainty about long-term effects and gene transfer.

Try three B6.2 Feeding the Human Race exam-style questions