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EnglandCombined Science

Biology: 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 does one cell become a whole organism through cell division, and what are stem cells used for?

The cell cycle and mitosis producing two genetically identical cells, the role of mitosis in growth, repair and asexual reproduction, stem cells in embryos, adult tissue and plant meristems, and the use of stem cells in medicine and the ethics involved.
A focused answer to the OCR Gateway GCSE Combined Science A topic B2 on cell division, covering the cell cycle, mitosis producing genetically identical cells, growth and repair, stem cells in embryos, adults and plant meristems, and the medical uses and ethics of stem cells.
9 min answer →

How are eukaryotic and prokaryotic cells built, and how do we measure their tiny structures under a microscope?

Eukaryotic and prokaryotic cells, the function of sub-cellular structures (nucleus, mitochondria, ribosomes, chloroplasts, cell wall, vacuole, plasmids), light and electron microscopy, the magnification equation, and the use of standard form and SI units for cell sizes.
A focused answer to the OCR Gateway GCSE Combined Science A topic B1 on cell level systems, covering eukaryotic and prokaryotic cells, sub-cellular structures, light and electron microscopy, the magnification equation, and using standard form for cell sizes.
9 min answer →

How do enzymes speed up the reactions of metabolism, and why do temperature and pH change how fast they work?

Enzymes as biological catalysts, the lock and key model and the active site, the effect of temperature, pH and substrate concentration on enzyme activity, denaturing, and the breakdown of carbohydrates, proteins and lipids by digestive enzymes.
A focused answer to the OCR Gateway GCSE Combined Science A topic B1 work on enzymes, covering enzymes as biological catalysts, the lock and key model, the effects of temperature, pH and concentration, denaturing, and the digestive enzymes amylase, protease and lipase.
9 min answer →

How do cells release energy by respiration and how do plants make glucose by photosynthesis?

Aerobic and anaerobic respiration and their word equations, photosynthesis as an endothermic reaction, the limiting factors of light intensity, carbon dioxide concentration and temperature, and the inverse square law relating light intensity to distance.
A focused answer to the OCR Gateway GCSE Combined Science A topic B1 on respiration and photosynthesis, covering aerobic and anaerobic respiration, photosynthesis as an endothermic reaction, limiting factors, and the inverse square relationship between light intensity and distance.
9 min answer →

How do substances move into and out of cells, and why do larger organisms need exchange surfaces?

Diffusion, osmosis and active transport as ways substances move across membranes, the factors affecting the rate of diffusion, surface area to volume ratio, and the adaptations of exchange surfaces such as alveoli, villi and root hair cells.
A focused answer to the OCR Gateway GCSE Combined Science A topic B2 on transport across membranes, covering diffusion, osmosis and active transport, the factors affecting diffusion rate, surface area to volume ratio, and adaptations of exchange surfaces.
9 min answer →

How do animals and plants move substances around their bodies through transport systems?

The human circulatory system (heart, blood vessels and blood), the double circulation, the structure of arteries, veins and capillaries, the components and roles of blood, and transport in plants by xylem and phloem with transpiration and translocation.
A focused answer to the OCR Gateway GCSE Combined Science A topic B2 on transport systems, covering the heart and double circulation, arteries, veins and capillaries, the components of blood, and transport in plants by xylem (transpiration) and phloem (translocation).
9 min answer →