1. 11.2 Movement

2. Understandings Statement Guidance 11.2.U1
Bones and exoskeletons provide anchorage for muscles and act as levers.
11.2.U2
Synovial joints allow certain movements but not others.
11.2.U3
Movement of the body requires muscles to work in antagonistic pairs.
11.2.U4
Skeletal muscle fibres are multinucleate and contain specialized endoplasmic reticulum.
11.2.U5
Muscle fibres contain many myofibrils.
11.2.U6
Each myofibril is made up of contractile sarcomeres.
11.2.U7
The contraction of the skeletal muscle is achieved by the sliding of actin and myosin filaments.
11.2.U8
ATP hydrolysis and cross bridge formation are necessary for the filaments to slide.
11.2.U9
Calcium ions and the proteins tropomyosin and troponin control muscle contractions.

3. Applications and Skills
Statement
Guidance
11.2.A1
Antagonistic pairs of muscles in an insect leg.
11.2.S1
Annotation of a diagram of the human elbow.
Elbow diagram should include cartilage, synovial fluid, joint capsule, named bones and named antagonistic muscles.
11.2.S2
Drawing labelled diagrams of the structure of a sarcomere.
Drawing labelled diagrams of the structure of a sarcomere should include Z lines, actin filaments, myosin filaments with heads, and the resultant light and dark bands.
11.2.S3
Analysis of electron micrographs to find the state of contraction of muscle fibres.
Measurement of the length of sarcomeres will require calibration of the eyepiece scale of the microscope.

4. 11.2.U1 Bones and exoskeletons provide anchorage for muscles and act as levers.

5. 11.2U.1 Bones – provide hard framework Protect vulnerable areas
Act as levers
Store minerals
Form blood cells in marrow

6. 11. 2. U. 2 Synovial Joints allow certain movements, but not others 11
11.2.U.2 Synovial Joints allow certain movements, but not others 11.2.S1 Draw and label human elbow

7. Hinge Joints vs Ball-&-Socket
Ball & Socket allows rotational movement
Hip, shoulder
Hinge joints include synovial cavities / fluid
Elbow, knee
Lubricates joint

8. Ligaments / Nerves Work like an elastic band – strengthens joints
Prevents over-extension
Nerves provide signals

9. Muscles and Tendons
Tendons attach muscles to bone
Muscles provide force for movement
Muscles can only contract
Occur in pairs to counteract each other

10. Picture of Mr. Adams’ “Guns”
11.2.U3 Movement of the body requires muscles to work in antagonistic pairs
Picture of Mr. Adams’ “Guns”

12. 11.2.U4 Three Types of Muscle
Skeletal – Attached to bones, responsible for movement:
Multinucleated and have specialized ER (Sarcoplasmic reticulum)
Smooth Muscle – Involuntary movement, stomach…
Cardiac Muscle
Heart muscle

13. 11.2.U5 Striated Muscle are made-up of long fibers called myofibrils
Myofibrils are made of sarcomeres

14. 11.2.U6 Muscle Fibers The functional unit of a muscle is called a sarcomere and is bordered by Z lines

15. 11. 2 S2 Draw a labeled diagram of a sarcomere 11. 2
11.2 S2 Draw a labeled diagram of a sarcomere 11.2.S3 Analysis of electron sarcomeres

16. Myosin head (low- energy configuration)
Figure 50.28
Thin filaments
Thick filament 1
Thin filament
Myosin head (low- energy configuration)
ATP
ATP
Thick filament 2 5
Thin filament moves toward center of sarcomere.
Myosin- binding sites
Actin
ADP
P i
Myosin head (low- energy configuration)
Myosin head (high- energy configuration
Figure Myosin-actin interactions underlying muscle fiber contraction.
ADP
ADP
P i
Cross-bridge
P i 3 4

17. 11.2.U7 The Sliding-Filament Model of Muscle Contraction
According to the sliding-filament model, filaments slide past each other longitudinally, producing more overlap between thin and thick filaments
11.2.U8 ATP Hydrolysis and cross bridge formation are necessary for filaments to slide
© 2011 Pearson Education, Inc.

18. 11.2.U9 Calcium Ions and the proteins tropomyosin and troponin control muscle contractions
Troponin has receptors for calcium ions, when Ca is released they activate
Tropomyosin fibers move to allow a cross bridge to form

20. 11.2.U8 ATP hydrolysis and cross bridge formation are necessary for the filaments to slide. AND 11.2.U9 Calcium ions and the proteins tropomyosin and troponin control muscle contractions.
edited from:

21. Overview: Signal comes from neuron, causes calcium release, and muscle response

22. Nature of science: Developments in scientific research follow improvements in apparatus - fluorescent calcium ions have been used to study the cyclic interactions in muscle contraction. (1.8)
Ashley and Ridgway (1968) were the first to study the role that Calcium ions (Ca2+) plays in the coupling of nerve impulses and muscle contraction. Their work was made possibly by the use of aequorin, a Ca2+ binding bioluminescent protein. Upon Ca2+-binding aequorin emits light. The timing of light emission peaks between the arrival of an electrical impulse at the muscle fibre and the contraction of the muscle fibre. This is consistent with theory of release of Ca2+ from the sarcoplasmic reticulum
The light emissions are detected and recorded using specially adapted microscopes and cameras.
Deduce the structure of aequorin from the molecular visualization.
A number of researchers have used fluorescent dyes to visualise and measure the movement of myosin and actin.
aequorin and the fluorescent dyes used in research only emit for a few short nano-seconds making them ideal to measure the rapid movements found in muscle cells.

23. Electron micrograph of human skeletal muscle
11.2.S3 Analysis of electron micrographs to find the state of contraction of muscle fibres.
Electron micrograph of human skeletal muscle
Analyse the micrograph and use it to answer the following:
Deduce whether the myofibrils are contracted or relaxed
Calculate the magnification of the electron micrograph
Measuring an individual sarcomere accurately is difficult due to their small size. Commonly scientists use the formula below: = total length of n sacromeres n
Measure the total length of five sarcomere from z-line to z-line
Calculate the mean length of a sarcomere
mean sarcomere length (μm)
1μm

24. 11.2.S3 Analysis of electron micrographs to find the state of contraction of muscle fibres.

25. What causes cramps? Still unclear…
Commonly linked to dehydration/loss of electrolytes
little evidence to back this
Only clear evidence is from muscle fatigue/overuse