OCR Gateway GCSE Biology A: Scaling up (B2) overview
An overview of the scaling up content (topic B2) in OCR Gateway GCSE Biology A (J247), mapping the cell cycle and mitosis, stem cells, diffusion, osmosis and active transport, surface area to volume ratio, exchange surfaces, the circulatory system and transport in plants, and how they are examined on the first biology paper.
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The second biology topic of OCR Gateway GCSE Biology A (specification J247) scales the story up from one cell to a whole organism. B2 Scaling up is examined on the first biology paper (J247/01 at Foundation, J247/03 at Higher). This page maps the topic and links to a focused answer page for each part.
The scaling up content
- The cell cycle and mitosis
- The stages of the cell cycle, how mitosis makes two genetically identical cells, and its role in growth, repair and asexual reproduction. See Mitosis and the cell cycle.
- Stem cells
- Undifferentiated cells, the sources (embryonic, adult and plant meristems), their uses in medicine and agriculture, and the ethical issues. See Stem cells.
- Diffusion, osmosis and active transport
- The three ways substances cross membranes, the factors affecting diffusion, the effect of osmosis on cells, and percentage change. See Diffusion, osmosis and active transport.
- Exchange surfaces and surface area
- Surface area to volume ratio, why large organisms need exchange surfaces and transport systems, and the adaptations of alveoli, villi and root hairs. See Exchange surfaces and surface area.
- The circulatory system
- The double circulation, the heart, arteries, veins and capillaries, and the components of blood. See The circulatory system.
- Transport in plants
- Xylem and phloem, the transpiration stream and translocation, the factors affecting transpiration, and stomata and guard cells. See Transport in plants.
How this topic is examined
Topics B1 to B3 are assessed on the first biology paper, which is 1 hour 45 minutes, worth 90 marks and 50% of the GCSE. Questions include multiple choice, short structured answers, calculations (surface area to volume ratio, percentage change) and six-mark extended responses such as tracing blood through the heart. Every paper also tests B7 practical skills, so the osmosis practical can be examined here.
How to study the scaling up topic
- Work from the specification statements. Each point is a checklist; questions are written from them.
- Learn definitions exactly. Diffusion, osmosis, active transport and transpiration are marked on precise wording.
- Drill the maths. Surface area to volume ratio and percentage change in osmosis appear repeatedly.
- Learn the structures. Know the heart chambers and vessels, the three blood vessels, and the components of blood.
- Master the osmosis practical. The potato cylinder method and its percentage change calculation are common.
For the official specification
OCR publishes the full specification, past papers and mark schemes at ocr.org.uk. Always revise from the current specification and OCR's own past papers, because question style is board-specific.