Eduqas A-Level Biology Section B options: a deep dive on immunology, the musculoskeletal system and neurobiology
A deep-dive Eduqas A-Level Biology guide to the three Component 3 Section B options: Immunology and disease, Human musculoskeletal anatomy, and Neurobiology and behaviour. Covers each option's content and the exam patterns Eduqas repeats, so you can revise whichever one your school teaches.
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What the Section B options actually demand
Component 3 of Eduqas A-Level Biology ends with a Section B worth 20 marks, in which you answer one optional topic. There are three options, and your school teaches one of them: Immunology and disease, Human musculoskeletal anatomy, or Neurobiology and behaviour. This guide covers all three so you can revise whichever one your school has chosen. The examiners test the same skills as the rest of the paper: precise recall and the application of that knowledge to data and unfamiliar contexts.
This overview summarises each option and the exam patterns Eduqas repeats. Each option has its own dot-point page with practice questions; this guide ties them together.
Option A: Immunology and disease
Pathogens (bacteria, viruses, fungi and protoctists) cause disease and spread in various ways. Non-specific defences (barriers, inflammation and phagocytosis) act fast against any pathogen. The specific response is targeted: an antigen-presenting cell displays the antigen, T helper cells activate the response, B lymphocytes are selected and divide into plasma cells (secreting specific antibodies) and memory cells, and T cytotoxic cells kill infected cells. Antibodies work by agglutination, neutralising toxins and marking pathogens. Active immunity (the body makes its own antibodies, with memory cells) lasts longer than passive immunity (antibodies received from elsewhere). Vaccination gives artificial active immunity, herd immunity protects the unvaccinated, and antibiotics kill bacteria but not viruses; overuse drives resistance.
Option B: Human musculoskeletal anatomy
The skeleton supports, protects, allows movement and makes blood cells. A synovial joint has cartilage, synovial fluid, a capsule and ligaments; tendons join muscle to bone. Muscles work in antagonistic pairs (such as biceps and triceps) because they can only pull. Skeletal muscle is made of fibres containing myofibrils of actin and myosin arranged in sarcomeres. In the sliding filament theory, calcium ions move tropomyosin off the actin binding sites, myosin heads bind and flex (the power stroke) to slide the actin in and shorten the sarcomere, and ATP detaches and re-cocks the heads. Injuries include sprains (ligaments), strains (muscle or tendon) and fractures.
Option C: Neurobiology and behaviour
The human brain has a cerebrum (higher functions and voluntary movement), a cerebellum (coordination and balance), a medulla oblongata (involuntary processes) and a hypothalamus (homeostasis and hormone control). The brain is studied by scanning (MRI, fMRI), EEG and lesion studies. Innate behaviour is inherited and present from birth; learned behaviour develops through experience. Types of learning include habituation, classical conditioning (Pavlov), operant conditioning (Skinner) and imprinting (Lorenz). Behaviour is shaped by natural selection because it affects survival and reproductive success.
How the Section B option is examined
A typical Eduqas profile for the option:
- Recall and definitions. The stages of the immune response; the structure of a synovial joint or sarcomere; the functions of the brain regions.
- Sequences. The specific immune response, the cross-bridge cycle of the sliding filament theory, or distinguishing types of learning.
- Applied questions. A primary-and-secondary-response graph; rigor mortis explained by ATP; identifying a type of learning from an experiment.
- Levels-of-response QER. Each option can supply the extended-response question, so practise a full account in your chosen option.
Check your knowledge
A mix of questions across the three options. Answer the ones for the option your school teaches, then check against the solutions.
- (Option A) State two non-specific defences of the body. (2 marks)
- (Option A) Explain why active immunity lasts longer than passive immunity. (2 marks)
- (Option B) Name the structures that join muscle to bone and bone to bone. (2 marks)
- (Option B) State the role of calcium ions in muscle contraction. (2 marks)
- (Option C) State the function of the cerebellum. (1 mark)
- (Option C) Distinguish between innate and learned behaviour. (2 marks)
- (Option A) Explain why antibiotics do not work against viruses. (2 marks)
- (Option B) Explain why muscles must work in antagonistic pairs. (2 marks)