OCR 2023 GCSE Combined Science B Twenty First Century Science J260/04: Combined science (Foundation Tier) Question Paper & Mark Scheme (Merged)

2 © OCR 2023 Stomach acid Clots the blood to prevent pathogens from entering cuts Skin Produces antibodies, or ingests and digests pathogens Platelet Barrier that prevents pathogens from entering the body White blood cell Can kill pathogens and stop them from reproducing 1 Pathogens can cause diseases in humans. Draw lines to connect each defence mechanism with the explanation of how it functions. Defence mechanism Explanation [3] 3 © OCR 2023 Turn over 2 (a) The plant genome is inside the nucleus of each cell. (i) What is a genome? ........................................................................................................................................... . ..................................................................................................................................[1] (ii) What is the function of the nucleus in a plant cell? Tick () one box. It controls what goes into and out of the cell. It controls how organisms develop and function. It maintains the shape of the cell. [1] (b) Plants make small organic molecules including sugars, fatty acids, glycerol and amino acids. Why is it important for plants to be able to make their own amino acids? ................................................................................................................................................... ...........................................................................................................................................[1] (c) Scientists can genetically engineer crop plants. Complete the description of genetic engineering.