20. What are the positions of
act in and myosin molecules in
the sarcomere before and
during the muscle
contraction?

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
Schematically act in attached
perpendicularly to sarcomere
extremities (longitudinal ) make
contact with filaments
positioned in middle ofthe
sarcomere in parallel to actin
filaments.

Before contraction the sarcomeres
extended (relaxed) since contact
between act and myosin filaments
only made by extremities. During
contraction in filaments slide
the myosin filaments the
sarcomeres shorten.