BIOSC 150 1nd Edition Lecture 9 Outline of Last Lecture I. Membrane and DiseaseOutline of Current Lecture 1. Subcellular structuresA. Actin Cystoskeleton2. Disease Current LectureThree types of filamentous proteins comprising the cytoskeleton:1. Microfilaments(actin) – small diameter, polymer made of actin monomers2. Intermediate Filaments – intermediate diameter, polymer made of various proteins depending on the cell type3. Microtubules – large diameter, polymer made of the proteins alpha and beta tubulin-Cytoskeletal filaments are long chains made up of repeating protein subunits (monomers)Microfilaments:-A subunit of actin-Chain, wounded to form a double helix (long strands)-Two forms of actin: 1. Globular 2. Filamentous, are constantly interconverting -Requires energy in the form of ATP-Composed of non-covalent bonds (due to the fact that they require less energy to break)-Actin filaments are asymmetric/ have polarity therefore making the whole polymer polar-Actin can form different types of bundles that help to shape the cell; these bundles include contractile bundles, gel like networks, and tight parallel bundlesFilapodium- highly dynamic environmental sensorsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Actin polymerizes under the plasma membrane and therefore causes it to move in and outApical Surface- top surface of a cellLamellipodia- push out membrane for movement, polymerizing actin into gel network in order to push the membrane out-Myosins are motor proteins that use the energy of ATP hydrolysis to travel along actin-Myosins have the ability to carry cargo-Mutations in myosin 5 disrupt melanosome transport (causes of albinism)-Myosin can move organelles and cytoplasm in plants-Actin filaments can form anti-parallel bundles that along with myosin, allow contraction (muscle cells and others)-Filamentous myosin effects contraction of anti-parallel actin
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