Actinin Molecules Form an Open Meshwork at the ________

Question

Actinin molecules form an open meshwork at the ________.
A) Z line
B) M line
C) H band
D) I band
E) A band

Accepted Answer

Actinin molecules are part of the thin filament in muscle cells and they anchor actin filaments to the Z line. Therefore, they form an open meshwork at the Z line. The other options listed (M line, H band, I band, A band) are all regions within a sarcomere, but none of them specifically relate to the formation of actinin meshwork.