Which of the following bands is isotropic?
Correct answer: D. I-band
- A. H-band
- B. A-band
- C. Z-line
- D. I-band
Explanation
The light band, which is also called the 'I' band, is isotropic. 'I' stands for isotropic because, in a polarising microscope, these bands are much less birefringent than the A bands.
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About Muscle Contraction
Muscle contraction is explained by the sliding filament model, in which myosin heads pull actin filaments within sarcomeres using ATP. The topic covers calcium, troponin, tropomyosin, the neuromuscular junction and relaxation, with attention to how filament length stays almost constant while the sarcomere shortens.
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