CAS BI 203 Lecture Notes - Lecture 21: Myosin, Calponin, Alpha Helix
14 Sep 2019
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Z disc: actin filaments are attached to z disc by their barbed end, middle of sarcomere defined by m line, myosin filaments are anchored to m line and project out in both directions. Be familiar with all of the details (each of the bands and the definitions of different parts: key to muscle contraction: actin and myosin ii filaments overlap on either side of. How do muscle fibers know when to contract: cycle regulated by ca2, presence contraction, absence no contraction, most muscle cells have a storage of calcium. Contractile ring dependent on calcium: contraction of the ring pinches the cell in two. Microtubules: biggest cytoskeletal elements, hollow rods of ~25 nm made up of tubulin, composed of dimers of alpha and beta tubulin that polymerize, with 13 protofilaments each. What if there is insufficient gtp-tubulin: the microtubule shrinks in a process known as dynamic instability.
