Thick filaments

Definition

Thick filaments are protein structures in muscle cells composed primarily of myosin. They interact with thin filaments during muscle contraction to produce force and movement.

5 Must Know Facts For Your Next Test

1. Thick filaments are primarily made up of the protein myosin.
2. Each thick filament is surrounded by six thin filaments in a hexagonal arrangement.
3. The heads of myosin molecules on thick filaments form cross-bridges with actin in thin filaments during muscle contraction.
4. Thick filaments are located in the A-band of the sarcomere, contributing to its dark appearance under a microscope.
5. ATP binding and hydrolysis on myosin heads provide the energy necessary for muscle contraction.

Review Questions

Related terms

Thin Filaments: Composed mainly of actin, these structures interact with thick filaments for muscle contraction.

Sarcomere: The basic functional unit of striated muscle fibers responsible for muscle contraction.

Myofibril: A long, filamentous organelle within muscle cells containing repeating units of sarcomeres.