BIOL 411 Lecture Notes - Lecture 22: Microtubule Organizing Center, Spindle Apparatus, Tubulin
4/06/16
bio411.01
Chapter 10: cell structure and cytoskeleton
• Tissues: a collection of cells that have a function
o 4 types:
▪ Epithelial: lining, ex: skin lining, lining of gut, lining of blood vessels, lining
of lungs, (anywhere where body interacts with outside world)
▪ Connective
▪ Nervous
▪ Muscular
• Organ: made of 2 or more tissues
o Ex: heart: muscle tissue, epithelial tissue, connective tissue
• Cell shape: mediated by cytoskeleton
• Cell adhesion: mediated by junctions and extracellular matrix
• Skin
o It is an organ
o 2 layers:
▪ 1. Epidermis- protective barrier-two way, meaning keeps bacteria out and
water in
• layers of epithelial cells form epithelial tissue
o major types of epithelial cells: keratinocytes and
melanocytes
▪ dermis- underneath, nutrients, support
• Connective tissue (few cells, but lots of extracellular matrix)
o Main type of cell: fibroblasts- stimulated by growth factors
in response to a wound and respond by stimulating growth
to heal the wound
• Many nerves and blood vessels
• Cytoskeleton
o Composed of 3 filaments: protein fibers that provide support, shape, movement,
and transport, all 3 are polymers of protein subunits
▪ Microtubules: thickest
• Composed of a heterodimer of tubulin monomers with one alpha
tubulin and one beta tubulin
• Protein= tubulin
• Protofilaments: a long chain of heterodimers that form a tube
• Functions: maintain cellular shape, organelles, transport within
cell (like highways), flagella and cilia, spindle apparatus in
mitosis/meiosis
• Centrosome (microtubule organizing center): structure within the
cell that divides early in mitosis and moves to opposite sides of
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