BIO 202 Lecture Notes - Lecture 4: Endoplasmic Reticulum, T-Tubule, Intercalated Disc
Document Summary
Signal molecule activates receptor and associated g protein, gprotein activates phospholipase c, an amplifier enzyme, plc converts phosopholipids into dag, which remains in membrane and ip3, which diffuses into cytoplasm, dag activates protein kinase c which phosphorylates proteins. Insulin binds to tyrosine kinase receptor: receptor phosphorylates insulin-receptor substrates, second messenger pathways alter protein synthesis and existing proteins, membrane transport is modified, cell metabolism is changed. In g proteins, alpha subunit drops gdp and picks up gtp. Beta/gamma subunits open ligand gated k+ channel, hyperpolarizing graded potential. Material for exam 2: skeletal muscle fibers are large, multinucleate cells that are striped or striated under the microscope, cardiac muscle is also striated but is smaller, branched, and uninucleate. Cells are joined by a series of junctions known as intercalated disks: smooth muscle fibers are small and lack striation, skeletal muscle is connected to bones and few tubes. Myosin head enables for interaction between myosin and actin.