Model+the+sliding+filament+hypothesis

Learn about the mechanism of muscle contraction in a visual, kinesthetic way.
 * The idea**

This list is flexible and limited only by imagination. Suggestions for a basic set are:
 * The equipment**
 * pipe cleaners
 * straws
 * plasticine
 * blue-tak
 * raisins
 * beans
 * wooden splints


 * Your task**
 * 1) Make a model showing stages of the actin-myosin binding and bending process which powers the sliding filament model.
 * 2) You have access to the above equipment, but you may use anything that comes to hand which you think will help.
 * 3) At each step in the model add annotations to indicate what is happening.
 * 4) Take a photo of each annotated stage in the cycle.
 * 5) Convert your photos to a short movie or presentation.

11.2 Muscles and movement has lots of useful animations and tutorials. In particular the Khan academy has a good tutorial and the i-Biology presentation has good simple notes and visuals, however there are several good animations and tutorials.
 * Good resources**


 * Elements that should be included in your model**
 * explanation of the effect of calcium on the myofibrils and what causes the release of calcium
 * As an ATP molecule binds to the myosin head (**change in shape/conformational change**), the head detaches from the actin.
 * The ATP-ase on the myosin head hydrolyses the ATP, forming ADP and Pi (still bound to the myosin).
 * This causes the change to the upright position of the myosin head. Binding and hydrolysing ATP puts energy into the system, and the head of the myosin molecule moves into the ‘cocked’/ right-angled position.
 * When the myosin binds to the actin (**forming a cross-bridge**), ADP and Pi are released, and the myosin head returns to its relaxed position (or nods forward), causing relative movement of the filaments.
 * Energy is transferred as work done by the muscles in contraction.
 * Indication of several myosin heads on a single fibre acting one after another, rather than all myosin heads acting in concert.
 * Myosin heads may bind and release up to 5 times per second.
 * A link from the detailed molecular events to the overall changes in the sarcomere, and relative movements (and widths) of the H-band, Z-band and I-band.

//This idea is based upon the [|sliding filament hypothesis] from Practical Biology//

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 * Examples of completed work**