Q. Read the given statements for skeletal muscle
(i) Thin filaments are firmly attached to the Z-line.
(ii) The light band is also called the I-band and contains mostly actin.
(iii) A sarcomere is the functional unit of a myofibril between two adjacent A-bands.
(iv) The central part of the thick filament, not overlapped by the thin filament is called the H-zone.
Which of these is/are CORRECT?

 2126  196 NTA AbhyasNTA Abhyas 2020Locomotion and Movement Report Error

Solution:

Skeletal muscles are also known as striated muscles and are under our control. These muscles have thin and thick filaments known as monofilaments or myofibrils whose functional unit is the sarcomere between the two Z-lines. There is the presence of alternate light and dark band s on the myofibrils. The striated appearance of these muscles is due to the presence of two proteins- actin and myosin. The light band or the Isotropic band has actin in it. In the centre of each light band is a fibre which bisects it, called the Z- line. The thin filaments are found to be attached firmly to this line. The H-zone is the central part of the thick filament.