Cell functions (47-51)

  1. Vacuoles

  • Large fairly permanent vesicles

  • In plants and unicellular eukaryotes

  • Storage of water, proteins, ions, wastes, anti predators chemicals

  1. Peroxisomes

  • detoxify harmful chemicles

    • Many in liver + Kidney

  1. Mitochondria

  • every transformation produce ATP from proteins, carbohydrates, lipids

  • Double membrane

  • Circular DNA

  • Ribosomes

  1. Plastids: in plant cells

Several types of


  • Leuciplast: White - Store Starch

  • Chromoplast: Red, yellow, orange pigments

  • Chloroplast: green Pigments - 3 membrane photosynthesis


  1. Cytoskeleton: 3D web of fibrous proteins

  • static function: shape + strength

  • Dynamic: entire cell intracellular movement

  • Three types:

    • MICROTUBULES = MT

    • Microfilaments = MF

    • Intermediate filaments = IF


A. MICROTUBULES

  • major highways

  • Consist of tubes (like a filled straw)

  • Made of protein named tubulin

  • Intracellular movement

  • Molecular motors “work” on MT

  • Dyneins = motors for cilia + flagella

  • Kinesins

  • Being carried

    • Vesicles

    • Organelles

  • Flagella + cilia

    • Covered with plasma membrane

    • 9 + 2 arrangement

    • Movement of entire cells

    • Cilia and flagella structurally identical

    • Flagella = long, few

    • Cilia = short, many

  • Basal Body = anchor point

    • 9 + 0

    • Triplets no motors

B. Microfilaments

  • polymers of a protein called actin forms a twisted double chain

  • Structural role: cell shape

    • One example = micro ills of intestinal cells

  • Intracellular movement: form small “roads” myosins

  • Muscle contraction: actin - myosin complex

  • Pseudo podia: membrane extensions

    • Pushed out by MF

  • Immune cells —> cancer cells


C. Intermediate filaments

  • very diverse compounds

  • Many proteins monomers

  • Cell shape + strength keratins


F. Intercellular junctions: connections between cells

  • “tunnels”

  • “Sealing”

  • “Spot welds”

  1. Tunnels for communication

  • animal cells (no walls): gap junctions

    • Proteins called connexons

  • Ions

  • Water

  • Monomers

  • Plant cells (walls): Plasmodesmata

    • Connect SER inside of each cell

  1. Sealing  for impermeability

  • Tight junctions

    • Protein stitching

  1. Spot welds for strength

  • Desmosomes

    • Proteins

G. Extracellular Matrix: stuff between and around cells

  • support/anchorage for cells

  • Cell — Cell adhesion

  • Wound repair


  • Collagens = long protein fibers

    • Strength and flexibility

  • Proteoglycans = glycoproteins

    • Wrapped around collagens

  • Elastin: provides elasticity

  • Lungs

  • Blood vessels

  • Urinary bladder

  • Skin


  • Connecting proteins

    • Connecting everything

    • Fibronectins

    • Integrins