| Date | May 2015 | Marks available | 3 | Reference code | 15M.3.SL.TZ2.5 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | Outline | Question number | 5 | Adapted from | N/A |
Question
Outline the function of myosin and actin in muscle contraction.
State the function of the following structures in the human elbow.
Synovial fluid
State the function of the following structures in the human elbow.
Biceps
Markscheme
a. formation of cross-bridges/myosin binds to the thin filament/actin;
b. Z-bands pulled towards each other;
c. sliding of actin and myosin filaments/shortening the sarcomere/I-band;
d. use of ATP to break cross-bridges / myosin releases actin when binding to ATP;
e. myosin heads re-set;
f. contraction ceases when myosin head detaches from the thin filament;
synovial fluid: avoids friction/lubricates / absorbs shock (at the elbow joint)
biceps: flexes arm/raises lower arm
Examiners report
Only the better students could outline the function of myosin and actin in muscle contraction.
N/A
N/A
