Movement 11.2 HL

This topic covers the basic structure of joints and the role of bones and exoskeletons in movement before looking in detail at the structure of sarcomeres in skeletal muscles and the processes of the sliding filament theory. Practical techniques in the topic include measuring sarcomere length and labelling diagrams of synovial joints.

Key concepts

Learn and test your biological vocabulary using these 11.2 Movement topic flash cards

Essentials

These slides summarise the essential understanding and skills in the topic Movement 11.2. 
They contain short explanations in text and images - great revision.

Read the slides and look up any words or details you find difficult to understand.

Summary

Summary list for 11.2 Movement

Skeletons and muscles

  • Bones and exoskeletons (e.g. insect legs) provide anchorage for muscles and act as levers.
  • Synovial joints allow certain movements but not others.
  • Muscles work in antagonistic pairs.

Muscle contraction

  • Skeletal muscle fibres are multi-nucleate and contain
    • specialised endoplasmic reticulum.
    • many myofibrils.
    • made up of contractile sarcomeres.
  • The sliding of actin and myosin filaments causes contraction.
  • Contraction requires ATP hydrolysis and cross bridge formation
  • Calcium ions and the proteins tropomyosin and troponin control muscle contractions.

Skills & applications

  • Know how to annotate a diagram of the human elbow. Include cartilage, synovial fluid, joint capsule, named bones and named antagonistic muscles.
  • The ability to draw labelled diagrams of the structure of a sarcomere, including Z lines, actin filaments, myosin filaments with heads, and the resultant light and dark bands.
  • The ability to find the state of contraction of muscle fibres in electron micrographs,
  • Experience of measurement of the length of sarcomeres using calibration of the eyepiece scale of the microscope.

Mindmaps

This diagram summaries the main sections of topic 11.2 about movement.
Test if you can draw something like these concept maps from memory.

Exam style questions

Sarcomere structure

Understanding the structure of sarcomeres and their dark and light bands is an important skill from this topic.

Answer the question below on a piece of paper, then check your answer against the model answer below.

Grasshoppers jump using contraction of muscles in their legs. Explain the structure of myofibrils in muscles and the contraction of sarcomeres in the myofibrils. [8]

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Test yourself

Multiple Choice questions

This is a self marking quiz containing questions covering the topic outlined above.
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Just for fun

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