BIOB10H3 Lecture Notes - Lecture 10: Myosin, Sarcomere, Myofibril
Document Summary
Actin motors: myosin ii function: myosin ii is present in several cell types but are especially prominent in muscles. In most cells, myosin ii is required for cell motility and cytokinesis during cell division. Muscle cells require myosin ii for muscle contraction. Muscle contraction: myosin ii function: muscle cells are long, cylindrical cells with hundreds of nuclei called muscle fibres. This is formed from a fusion of several smaller cells. Myofibrils are composed of organized repeating structures called sarcomeres: sarcomeres are made up of thick and thin filaments with regions of overlap between them. The thin filaments in the sarcomeres are called microfilaments (actin filaments) and thick filaments are called myosin ii bipolar filaments. These filaments give the muscles the striped or striated appearance. When the sarcomere contracts, the muscles also contract. Muscle contractions: the role of actin binding proteins: calcium binding proteins are bound to thin filaments. This regulates the interaction between myosin heads and thin filaments.
