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Communication, Homeostasis and Energy

Module 5 is the first of the two A-level-only modules. It brings together the communication systems of the body (neuronal and hormonal), the homeostatic mechanisms they support, and the two fundamental energy-transducing pathways (photosynthesis and respiration). The module rewards students who can trace a signal from its detection all the way through to the cellular and metabolic response it triggers.

Core Role

  • Establish cell signalling, homeostasis and feedback as organising principles for animal physiology.
  • Cover the structure and mechanism of neurones, action potentials and synapses in full.
  • Cover the endocrine system: adrenal glands, pancreas, blood glucose regulation and diabetes.
  • Extend plant biology to include tropisms, the five classes of plant growth regulator and their commercial uses.
  • Cover the full biochemical pathways of photosynthesis (light-dependent and Calvin cycle) and aerobic and anaerobic respiration.

Learning Objective Map

Each Module 5 topic page now opens with a specification-aligned Learning Objectives section. Use these links to move from each topic code to the control loops, signalling pathways and energy pathways taught in the notes.

Topic Objective map focus
5.1.1 Communication and homeostasis signalling systems; homeostasis; feedback; thermoregulation
5.1.2 Excretion as an example of homeostatic control excretion; liver; kidney function; osmoregulation; urine testing
5.1.3 Neuronal communication neurones; action potentials; reflexes; synapses; muscle contraction
5.1.4 Hormonal communication endocrine glands; adrenaline; blood glucose; second messengers; diabetes
5.1.5 Plant and animal responses tropisms; plant hormones; abiotic and herbivory responses; brain and muscle control
5.2.1 Photosynthesis chloroplast structure; light-dependent reactions; Calvin cycle; limiting factors
5.2.2 Respiration glycolysis; link reaction; Krebs cycle; oxidative phosphorylation; anaerobic pathways

Topic Pages