Myofibrils contain:
Correct answer: D. Both B and C
- A. Tendons and ligaments
- B. Thick filaments
- C. Thin filaments
- D. Both B and C
Explanation
Option D is correct. Myofibrils are the contractile units of muscle fibers. They are made up of repeating units called sarcomeres. Sarcomeres contain thick and thin filaments, which are made up of the proteins myosin and actin. Thick filaments: Thick filaments are made up of the protein myosin. Myosin is a long, rod-shaped protein. The thick filaments are arranged in the center of the sarcomere. Thin filaments: Thin filaments are made up of the protein actin. Actin is a long, thin protein. The thin filaments are attached to the Z discs, which are located at the ends of the I band.
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About Support and Movement
Support and movement covers the axial and appendicular skeleton, bone structure, joints and the arrangement of skeletal muscles. Muscle contraction is explained through actin, myosin, sliding filaments, calcium ions and ATP, while arthritis is distinguished as a disorder of joints rather than a normal part of movement.
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