Question

Biochemical evidence supporting the sliding filament model of muscle contraction includes the observation that

A) myosin light chains can be phosphorylated.
B) titin connects each end of a thick filament to a Z line.
C) TnC binds Ca₂₊
D) actin has polymerization ATPase activity.
E) myosin has an ATP-dependent crossbridge cycle.

Answer 1

The biochemical evidence supporting the sliding filament model of muscle contraction involves TnC binding to Ca²⁺, which triggers the exposure of myosin binding sites on actin filaments and allows for the formation of cross-bridges.

Step-by-step explanation:

The biochemical evidence supporting the sliding filament model of muscle contraction includes the observation that TnC binds Ca²⁺. When calcium ions bind to troponin C (TnC), it triggers a series of molecular events that allow for the movement of the muscle filaments. This binding initiates the exposure of myosin binding sites on actin filaments, allowing myosin to bind to actin and form cross-bridges. This cross-bridge formation generates force and leads to muscle contraction.