Use the information provided to calculate the length of the myofibril after contraction.

Give your answer in mm and in standard form.

Show your working.

Answer ______________ mm

Which statement correctly describes the changes in length in a sarcomere when a myofibril contracts?

Tick (✓) one box.

☐ H-zone decreases, I-band increases, A-band decreases

☐ H-zone increases, I-band decreases, A-band decreases

☐ H-zone decreases, I-band decreases, A-band no change

☐ H-zone increases, I-band increases, A-band no change

Fast muscle fibres have a higher concentration of glycogen than slow muscle fibres.

Explain how the difference in glycogen concentration is related to the different properties of these muscle fibres.