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

Medium
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Question 5
Medium

A myofibril contains 250 sarcomeres connected in series. Figure 1 shows a schematic diagram of a relaxed sarcomere.

Figure 1: Diagram of a relaxed sarcomere showing the different bands and zones.

The length of every relaxed sarcomere is 2.2 μm2.2\ \mu\text{m}2.2 μm.

a.

During contraction, the length of each sarcomere decreases by 14%. Calculate the length of this myofibril after contraction. Give your answer in mm\text{mm}mm and in standard form. Show your working.

[4]
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)