Two statements are given: Statement I: ‘A’ band contains the myosin filament. Statement II: ‘I’ band contains only actin filament. Choose the correct option -

Correct option is C

(c) Both the statements I and II are correct Sol. In muscle fiber structure, the sarcomere is the basic contractile unit, and it consists of various bands and zones.
· Statement I is correct: The A band contains myosin filaments, which are thick filaments responsible for muscle contraction. The A band is the dark band seen under a microscope due to the overlapping of myosin filaments with actin filaments.
· Statement II is also correct: The I band contains only actin filaments, which are thin filaments. The I band is the lighter band and is located on either side of the A band. It consists of actin filaments and part of the sarcomere where there is no overlap with myosin filaments.
Information Booster:
1. The A band is the dark band in the sarcomere, formed by the overlapping of thick myosin filaments with thin actin filaments.
2. The I band is a light band that contains only actin filaments, and it shortens during muscle contraction.
3. The Z line defines the boundaries of each sarcomere and is where the actin filaments anchor.
4. The H zone within the A band is the area where there is no overlap between actin and myosin filaments.
5. The M line is the central line of the sarcomere where myosin filaments are anchored.
Additional Information:
· (a) Only statement I is correct: This is incorrect because both statements I and II are correct.
· (b) Only statement II is correct: This is incorrect because both statements I and II are correct.
· (d) Both the statements I and II are incorrect: This is incorrect because both statements are actually correct.