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Topic 1: Biological molecules
Biological building blocks
3.1.1 - Monomers and PolymersThis lesson introduces the small biological building blocks called monomers and the larger molecules made by joining them. It connects condensation and hydrolysis through the bonds they form or break and the opposite roles of water in each reaction.
3.1.2 - CarbohydratesThis lesson follows carbohydrates from monosaccharide structure through glycosidic bonds to storage and structural polysaccharides. It then links those molecular differences to starch, glycogen and cellulose functions before using biochemical tests to distinguish reducing sugars, non-reducing sug...
3.1.3 - LipidsThis lesson examines how glycerol, fatty acids and phosphate-containing groups give triglycerides and phospholipids different properties. It connects saturation and molecular shape to packing, energy storage and membrane formation, then applies lipid solubility in the emulsion test.
Proteins and enzymes
3.1.4.1 - General Properties of ProteinsThis lesson traces proteins from the common structure of amino acids to peptide bonds, polypeptides and the four levels of protein structure. It connects interactions between R groups to three-dimensional shape and function, then uses the Biuret test to detect peptide bonds.
3.1.4.2 - Many Proteins Are EnzymesEnzymes connect the precise tertiary structure of proteins to the control of biological reactions. This lesson develops models of enzyme action, explains how conditions and concentrations affect rate, and compares the ways inhibitors regulate enzyme-controlled pathways.
RP01 - Enzyme-Controlled Reaction RateThis practical links enzyme-rate theory to the design of a controlled investigation. It develops a trypsin-casein method, then considers variables, data processing, safety and improvements that can be transferred to other named variables.
Nucleic acids and ATP
3.1.5.1 - Structure of DNA and RNADNA and RNA are built from the same type of monomer but differ in ways that suit their roles. This lesson moves from nucleotide structure and polynucleotide formation to the organisation of DNA and RNA, then links molecular structure to information storage and transfer.
3.1.5.2 - DNA ReplicationDNA must be copied before a cell divides so that each daughter cell receives the same genetic information. The copying mechanism is called semi-conservative replication, and it maintains genetic continuity between generations of cells.
3.1.6 - ATPATP is the molecule cells use for immediate energy transfer. It is small, recycled continuously, and links energy-releasing processes such as respiration and photosynthesis to energy-requiring reactions inside the cell.
Water and inorganic ions
3.1.7 - WaterWater is a major component of cells. Its importance in biology comes from two linked features: water is dipolar, and neighbouring water molecules form hydrogen bonds. Those features explain why water can act as a metabolite, an important solvent, a thermal buffer, an efficient coolant when it eva...
3.1.8 - Inorganic IonsInorganic ions occur in solution in the cytoplasm and body fluids of organisms, sometimes in high concentrations and sometimes in very low concentrations. Their roles depend on their charge and the way they interact with other molecules. For AQA, the key examples are hydrogen ions in pH, iron ion...
Topic 2: Cells
Cell structure and study
3.2.1.1 - Structure of Eukaryotic CellsThis lesson examines how the main structures of eukaryotic cells support energy transfer, control, synthesis, transport and support. It also connects organelle abundance to cell specialisation and shows how specialised cells are organised into tissues, organs and organ systems.
3.2.1.2 - Structure of Prokaryotic Cells and of VirusesThis lesson compares the core structure of prokaryotic cells with that of eukaryotic cells, then distinguishes cells from virus particles. The comparison links the location and form of genetic material to ribosomes, cell walls, optional bacterial structures and host-dependent viral replication.
3.2.1.3 - Methods of Studying CellsThis lesson develops the measurements and methods used to study cells, from magnification and graticule calibration to optical and electron microscopy. It then connects image quality and artefacts with cell fractionation, where organelles are separated for biochemical study.
Cell division
3.2.2 - All Cells Arise from Other CellsThis lesson follows genetic material through the cell cycle, mitosis and cytokinesis, linking chromosome behaviour to growth, repair and cancer treatment. It also contrasts eukaryotic cell division with binary fission and with the host-dependent production of virus particles.
RP02 - Root Tip Mitosis and Mitotic IndexThis practical links careful slide preparation to recognising mitotic stages in a root-tip meristem. You will also use cell counts and calibrated measurements to calculate mitotic index and actual cell size, then consider how sampling and preparation affect the conclusions.
Membranes and transport
3.2.3 - Transport Across Cell MembranesCells survive because their membranes are selective rather than sealed shut. In this lesson, we move from the fluid-mosaic structure of membranes to the main transport mechanisms, and then finish with the adaptations that make transport fast in specialised cells.
RP03 - Water Potential of Plant TissueThis practical uses a dilution series to find the concentration of solute that is isotonic with plant tissue. By measuring how the mass of potato chips changes in known sucrose solutions, you can identify the point at which there is no net movement of water and use that to infer the water potenti...
Cell recognition and immunity
Topic 3: Organisms exchange substances with their environment
Exchange principles and gas exchange
Digestion and absorption
Mass transport and dissection
Topic 4: Genetic information, variation and relationships between organisms
Genetic information and variation
Species, biodiversity and investigation
Topic 5: Energy transfers in and between organisms
Photosynthesis and investigation
Respiration and investigation
Ecosystem energy and nutrients
Topic 6: Organisms respond to changes in their internal and external environments
Responses and receptors
Nervous coordination and effectors
Homeostasis and control
Topic 7: Genetics, populations, evolution and ecosystems
Inheritance and population genetics
Evolution and speciation
Ecosystems and fieldwork
Topic 8: The control of gene expression
Mutation and gene expression
Genomes and biotechnology