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Skeletal muscles are stimulated to contract by nerves and act as effectors (A-level only)

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Question 2

A myofibril contains 40 sarcomeres connected in series. Figure 1 shows a schematic diagram of a relaxed myofibril. Diagram showing adjacent sarcomeres in a relaxed myofibril, with labeled regions including the H-zone, I-band, and A-band. Below the diagram, an arrow indicates 'Length of sarcomere = 2.5 \mu m'. The length of every relaxed sarcomere is 2.5 μm2.5\text{ }\mu\text{m}2.5 μm.

a.

During contraction, the length of each sarcomere decreases by 12%12\%12%. Calculate the length of this myofibril after contraction. Give your answer in mm\text{mm}mm and in standard form. Show your working.

[3]
b.

Describe what happens to the lengths of the H-zone, I-band, and A-band when a myofibril contracts.

[3]

Skeletal muscles are stimulated to contract by nerves and act as effectors (A-level only) Questions

  1. A Level
  2. /Biology
  3. /Skeletal muscles are stimulated to contract by nerves and act as effectors (A-level only)