Question

Sarcomeres are indeed the smallest functional units of muscle fibers, comprised of thick and thin filaments, and are responsible for muscle contraction. They are contained within myofibrils that span the length of muscle fiber, giving it its striated appearance.

a) The myofibrils in muscles are responsible for muscle contraction.
b) Sarcomeres are the smallest functional units of muscle fibers.
c) The striated appearance of muscle fibers is due to the arrangement of sarcomeres.
d) Thick and thin filaments within sarcomeres play a crucial role in muscle function.

Answer 1

Sarcomeres, which contain thick myosin and thin actin filaments, are the basic contractile units of muscle fibers and are responsible for muscle contraction.

Step-by-step explanation:

Sarcomeres are the functional units of muscle fibers, essential for muscle contraction. These units are composed of alternating thick and thin filaments of myosin and actin respectively, which slide past each other to shorten the sarcomere, leading to muscle contraction. Each sarcomere is delimited by Z-discs and extends from one Z-disc to the next, with its contraction achieved by the interaction between the filaments. Troponin and tropomyosin are regulatory proteins that control the binding of myosin to actin. The striated appearance of muscle tissue is due to the regular repeating arrangement of sarcomeres within the muscle fibers.