13.10

Question 1

Briefly describe the sliding filament model. (2 marks)

Answer 1

Actin and myosin filaments must slide past each-other (within myofibrils) for muscles to contract.

Question 2

What causes movement? (2 marks)

Answer 2

Simultaneous contraction of sarcomeres causes the myofibrils and muscle fibres to contract (which is enough force to pull on a bone).

Question 3

What do the myosin filaments pull inwards towards the centre of the sarcomere, and what does this result in? (4 marks)

Answer 3

Actin filaments

Light band narrows
Z lines move closer together (shorter sarcomere)
H-zone narrows