Sliding Filament Theory

Study Questions on the Sliding Filament Theory:

1.     According to the sliding filament theory, when a muscle cell contracts, the __________ filaments slide past the ___________ filaments and the ____________ shortens.

2. List the six most important chemicals involved in muscle contraction.

3. Where is myosin found in skeletal muscle cells?

a. in the thin filaments

b. in the thick filaments

c. in the sarcoplasmic reticulum

d. in the terminal cisternae

e. in the T tubules

4. What two important binding sites are found on the cross bridges (heads) of myosin?

5. What three protein molecules are the thin filaments made of?

6.     Actin contains binding sites for _______________.

7.     What is the function of tropomyosin?

8. What is the function of troponin?

9. Identify the parts of the thin filament below.

10. What causes the tropomyosin to move away from the myosin binding sites on the actin?

11. What causes the release of calcium ions into the cytosol from the terminal cisternae?

12. What causes the myosin binding sites on actin to be exposed?

13. What causes the tropomyosin to cover back over the actin binding sites?

14. What is required to move the calcium ions from the cytosol back into the sarcoplasmic reticulum?

15. After a sarcomere has contracted fully and the calcium ion concentration within the cytosol decreases, what happens within the sarcomere?