What is the Functional Contractile Unit of the Myofibril Where

Question

What is the functional contractile unit of the myofibril where muscle tension is produced?
A)sarcomere
B)A band
C)sarcolemma
D)I band

Accepted Answer

The sarcomere is the functional contractile unit of the myofibril where muscle tension is produced. It includes the overlapping actin and myosin protein filaments and is responsible for the striated appearance of skeletal muscle fibers. Choice B refers to a region of the sarcomere where thick filaments are present, but it does not encompass the entire sarcomere. Choice C refers to the plasma membrane of a muscle fiber and is not directly involved in muscle contraction. Choice D refers to the region of the sarcomere where only thin filaments are present.