GCSE Biology

Cells and organisation
revision.

Cell structure, microscopy, transport, enzymes and the jump from cells to systems.

Cells and organisation guides

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05

Eukaryotic and prokaryotic cells

Compare eukaryotic and prokaryotic cells for GCSE Biology: nucleus versus a DNA loop, plasmids, organelles, and the diagram tests that decide Combined and Triple marks.

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06

Animal and plant cells

Label animal and plant cells for GCSE Biology: nucleus, mitochondria, ribosomes, cellulose wall, chloroplasts, vacuole, and the structure–function links examiners actually mark.

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07

Specialised cells

Link structure to function in GCSE Biology specialised cells: sperm, egg, nerve, muscle, root hair, palisade, xylem and phloem, with the adaptation sentences that score.

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08

Microscopy and magnification

Calculate magnification for GCSE Biology, convert mm to µm to nm, and compare light and electron microscopes on resolution, living specimens and which organelles you can actually see.

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09

Bacterial cells

Label a bacterial cell for GCSE Biology: chromosomal DNA loop, plasmids, flagella, cell wall, cytoplasm and membrane, and why bacteria lack a nucleus and mitochondria.

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10

Diffusion

Define diffusion for GCSE Biology: net movement down a concentration gradient, no energy from respiration, and the factors that speed gas exchange in alveoli, leaves and villi.

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11

Osmosis

Define osmosis for GCSE Biology: water from a dilute to a more concentrated solution through a partially permeable membrane, turgor, plasmolysis and the potato-chip graph.

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12

Active transport

Explain active transport for GCSE Biology: movement against a concentration gradient using energy from respiration, root-hair mineral ions, and why mitochondria pack into those cells.

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13

Osmosis required practical

Plan the GCSE Biology potato-chip osmosis practical: independent, dependent and control variables, percentage change in mass, blotting, and how the graph crosses zero at the isotonic point.

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14

Enzyme active site

Explain the lock-and-key model for GCSE Biology: enzymes as protein catalysts, complementary active sites, specificity, and why a changed shape means the reaction stops.

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15

Enzyme temperature and pH

Read enzyme graphs for GCSE Biology: rate rises with temperature to an optimum, then falls as the active site denatures, and pH peaks in a bell curve around pepsin, amylase or trypsin.

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16

Amylase required practical

Run the GCSE Biology amylase–starch practical: iodine end-point, water baths, buffers, 1/time as rate, and how to investigate temperature or pH without mixing up the variables.

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17

Mitosis

Describe mitosis for GCSE Biology: DNA replication, two genetically identical diploid body cells, and why growth, repair and asexual reproduction use mitosis — not meiosis.

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18

Meiosis

Explain meiosis for GCSE Biology: two divisions, four genetically different haploid gametes, 46 to 23 chromosomes, and why fertilisation then restores the diploid number.

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19

Stem cells

Compare embryonic, adult and meristem stem cells for GCSE Biology: unspecialised cells that can differentiate, bone-marrow treatments, therapeutic cloning, and the ethics examiners expect.

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20

Cancer and tumours

Explain cancer for GCSE Biology: uncontrolled mitosis, benign versus malignant tumours, secondary tumours (metastasis), and lifestyle and genetic risk factors in Combined and Triple language.

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21

Food tests required practical

Plan the GCSE Biology food-tests required practical: Benedict’s for reducing sugars, iodine for starch, biuret for protein, Sudan III for lipids, safety, controls and how to read a positive result.

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More GCSE Biology
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Teacher-written GCSE Biology revision for Combined and Triple Science: cell structure, osmosis, enzymes, photosynthesis, respiration, infection, homeostasis, inheritance and ecology.

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