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EnglandBiology

B2 Scaling up

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do substances move into and out of cells, and which processes need energy?

Diffusion, osmosis and active transport as ways substances move across cell membranes, the factors affecting the rate of diffusion, the effect of osmosis on plant and animal cells, and calculating percentage change in mass in the osmosis practical.
A focused answer to the OCR Gateway GCSE Biology A topic B2 on diffusion, osmosis and active transport, covering the definitions, the factors affecting diffusion, the effect of osmosis on cells, the osmosis practical and percentage change calculations.
10 min answer →

Why do big organisms need exchange surfaces when single cells can rely on diffusion alone?

Surface area to volume ratio and how it changes with size, why large organisms need specialised exchange surfaces and transport systems, and the adaptations of exchange surfaces such as alveoli, villi and root hairs.
A focused answer to the OCR Gateway GCSE Biology A topic B2 on surface area to volume ratio and exchange surfaces, covering how the ratio changes with size, why large organisms need exchange surfaces and transport systems, and the adaptations of alveoli, villi and root hairs.
9 min answer →

How does one cell divide into two identical cells, and why does the body need this?

The cell cycle (growth and DNA replication, mitosis, cytokinesis), mitosis producing two genetically identical diploid daughter cells, and the role of mitosis in growth, repair and asexual reproduction.
A focused answer to the OCR Gateway GCSE Biology A topic B2 on the cell cycle and mitosis, covering the stages of the cell cycle, how mitosis produces two genetically identical cells, and its role in growth, repair and asexual reproduction.
9 min answer →

What are stem cells, where are they found, and how might they treat disease?

Stem cells as undifferentiated cells that can divide and differentiate, the sources of stem cells (embryonic, adult and plant meristems), the uses of stem cells in medicine and agriculture, and the ethical issues raised by their use.
A focused answer to the OCR Gateway GCSE Biology A topic B2 on stem cells, covering undifferentiated cells and differentiation, embryonic, adult and plant stem cells, their uses in medicine and agriculture, and the ethical issues.
9 min answer →

How does the heart pump blood around two circuits, and how is blood adapted to its job?

The human double circulatory system, the structure and function of the heart, the differences between arteries, veins and capillaries, and the components of blood (red blood cells, white blood cells, platelets and plasma) and their functions.
A focused answer to the OCR Gateway GCSE Biology A topic B2 on the circulatory system, covering the double circulation, the structure and function of the heart, arteries, veins and capillaries, and the components of blood and their functions.
10 min answer →

How do plants move water up to their leaves and sugars to where they are needed?

Transport in plants by xylem (water and mineral ions) and phloem (dissolved sugars), the transpiration stream and translocation, the factors affecting the rate of transpiration, and the role of stomata and guard cells.
A focused answer to the OCR Gateway GCSE Biology A topic B2 on transport in plants, covering xylem and phloem, the transpiration stream and translocation, the factors affecting transpiration rate, and the role of stomata and guard cells.
9 min answer →