What are the roles of troponin and tropomyosin?

Troponin is the sarcomeric Ca2+ regulator for striated (skeletal and cardiac) muscle contraction. On binding Ca2+ Tn transmits information through structural changes throughout the actin-tropomyosin filaments, activating myosin ATPase activity and muscle contraction. troponin moves tropomyosin, exposing myosin binding sites on actin. myosin heads attach to binding sites on actin. Tropomyosin covers myosin binding sites on actin.

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.