| Date | November 2009 | Marks available | 3 | Reference code | 09N.3.SL.TZ0.5 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Draw | Question number | 5 | Adapted from | N/A |
Question
Draw a labelled diagram to show the structure of a skeletal muscle sarcomere.
[3]
a.
Outline the role of myoglobin in muscle fibres.
[2]
b.
Markscheme
Award [1] for each structure clearly drawn and correctly labelled.
light and dark bands;
Z line;
(thin) actin filaments shown with no gap between these and Z line;
(thick) myosin filaments shown with heads;
a.
binds oxygen when level is high;
releases oxygen when level is low;
acts as an oxygen store;
allows muscles to continue with aerobic respiration for longer;
b.
Examiners report
Some very poor diagrams were seen. The structure of a skeletal muscle was drawn by many of the candidates, without showing the sarcomere.
a.
Many candidates knew that myoglobin is used as an oxygen store.
b.
