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6. Sarcomeres are contractile units

  • True
  • False

7. ADP and Pi are released when...

  • tropomyosin shifts exposing myosin binding sites on the actin
  • the myosin head binds to the myosin binding sites on the actin forming cross bridges
  • calcium ions diffuse from the sarcoplasmic reticulum through the sarcoplasm towards the actin

8. ADP and Pi are released when ATPase on the myosin head hydrolyses the attatched ATP

  • True
  • False

9. The myosin head detatches from the actin when ATP binds to it

  • True
  • False

10. A sarcolemma is...

  • a contractile unit
  • the cell surface membrane of a muscle cell
  • the cytoplasm of a muscle cell

11. When filaments in a contracted sarcomere are looked at under a microscope...

  • the central lighter coloured band is no longer visible
  • the central intermediate coloured band is no longer visible
  • the central dark coloured band is no longer visible

12. Muscle cells do not contain many mitochondria

  • False
  • True

13. Striated means...

  • striped
  • smooth
  • strong

14. In rigor motis there is no ATP to detach the myosin head

  • True
  • False