Centrioles & Related Organelles Three functions of microtubules & microfilaments: assist cellular movement gives cell an internal cytoskeleton anchors organelles

Muscle Contraction Why are microfilaments thought to be involved in muscle contraction? Microfilaments have a composition similar to actin and myosin (two proteins used in the contraction of muscles) More on this much later!!! 

Where do we find microtubules? Cilia Centrioles Flagella Cytoplasm/basal bodies What is the function of cilia & flagella? Involved in movement How do cilia & flagella differ? Cilia are shorter than flagella Often there are many cilia & one or two flagella

Here’s the internal structure of cilia & flagella. Description: Membrane bound cylinders; inside there are 9 microtubule pairs arranged in a circle around 2 central microtubules. Called a “9 + 2” pattern of microtubules

How are basal bodies related to cilia? Each cilia or flagella has a basal body at its base (in cytoplasm) They organize the structure of the cilia/flagella Arranged in “9+0” pattern (9 microtubule triplets)

How are centrioles related to basal bodies? Also have 9+0 pattern of microtubules Give rise to basal bodies How are centrioles important for mitosis in animal cells? Involved in appearance/disappearance of spindle apparatus (pulls apart chromatids)

Another look at flagella/basal body relationship…