A2 Biology: Unit 5 CT
SLIDING FILAMENT THOERY
Each sarcomere gets shorter when the muscle contracts, so the whole muscle gets shorter. But the dark
band, which represents the thick filament, does not change in length. This shows that the filaments don’t
contract themselves, but instead they must slide past each other. This sliding filament theory was first
proposed by Huxley and Hanson in 1954, and has been confirmed by many experiments since.
A2 Biology: Unit 5 CT
When do these parts of the myofibril change?
Arrange the sequence of events into the correct order
Correct Sequence
1. …………………………………………………………………………………………………………………………………………………………..
2. …………………………………………………………………………………………………………………………………………………………..
3. …………………………………………………………………………………………………………………………………………………………..
4. …………………………………………………………………………………………………………………………………………………………..
5. ………………………………………………………………………………………………………………………………………………………….
6. …………………………………………………………………………………………………………………………………………………………..
7. …………………………………………………………………………………………………………………………………………………………..
8. …………………………………………………………………………………………………………………………………………………………..
A2 Biology: Unit 5 CT
Using the sequence from above – write the correct statement next to the diagram
A2 Biology: Unit 5 CT
ATP
→
ADP + Pi