Question

Choose the wrongly matched pair

• A. Portion of myofibril between two Z-lines $\to$ Sarcomere
• B. Isotropic band $\to$ Actin
• C. Anisotropic band $\to$ Myosin
• D. Central part of I-band $\to$ M-line
• E. Central part of A-band $\to$ H-zone

Answer 1

The correct option is D Central part of I-band $\to$ M-line

After going through the given diagram, the following conclusions can be made :

1. The sarcomere is the portion between two Z lines and is the functional unit of contraction.
2. The actin filaments form the isotropic band due to their refractive index.
3. The myosin filaments form the anisotropic band due to the refractive index in presence of light.
4. The central part of I band is Z line and not the M line. It is the incorrect option.
5. The central part of A band is H zone, which is not overlapped by the actin filaments.

So, the correct option is 'Central part of I-band → M-line'.