Edexcel International A Level Biology, topic 7
Respiration, Muscles and the Internal Environment
Respiration, Muscles and the Internal Environment is topic 7 of Pearson Edexcel International A Level Biology (YBI11) and is examined in Unit 5. It covers how cells release energy as ATP, how muscles contract, how the heart and breathing respond to exercise, and how the body keeps its internal environment stable, including the work of the kidney.
Revision notes
Worksheet
FlashcardsSubtopics
Work through them in order. Each one has notes, exam questions and flashcards, and a PDF of each.
- 1Stages of respiration A Level onlySpec 7.1–7.5Glycolysis, the link reaction, the Krebs cycle and oxidative phosphorylation, plus anaerobic respiration and what happens to lactate.NotesQuestions 8Flashcards 14
- 2Respiratory quotient and respiration practicals A Level onlySpec 7.6–7.8The respiratory quotient, and the two core practicals on respiration in yeast and with a simple respirometer.NotesQuestions 7Flashcards 8
- 3Muscles and movement A Level onlySpec 7.9–7.11How muscles, tendons, ligaments and bones produce movement, the structure of a muscle fibre, and the sliding filament theory.NotesQuestions 6Flashcards 14
- 4The heart, ventilation and exercise A Level onlySpec 7.12–7.15How the heartbeat is coordinated and monitored, how heart and ventilation rates are controlled in exercise, adrenaline, and spirometer data.NotesQuestions 9Flashcards 15
- 5Homeostasis, hormones and the kidney A Level onlySpec 7.16–7.22Negative and positive feedback, homeostasis and thermoregulation, hormones switching genes, and the kidney's role in excretion and osmoregulation.NotesQuestions 8Flashcards 18
Whole topic
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