AP Biology

CYTOSKELETON

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Cells gotta work to live! What jobs do cells have to do?

make proteins

proteins control every

cell function

make energy

for daily life

for growth

make more cells

growth

repair

renewal

AP Biology 2007-

2008

Making New Cells

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Cytoskeleton

Function

structural support maintains shape of cell

provides anchorage for organelles

protein fibers

microfilaments, intermediate filaments, microtubules

motility cell locomotion

cilia, flagella, etc.

regulation

organizes structures

& activities of cell

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Microtubules, Microfilaments, and

Intermediate Filamentshttp://www.youtube.com/watch?v=x2ElL2VVKi8&feature=related

Summarize in a table.

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CytoskeletonMicrotubules: tubes composed of spiraling tubulin

in two-part subunits.

Function: shape & support

chromosome movement (centriole, spindle fibers)

movement of organelles (serve as tracks)

movement of cellular appendages (cilia, flagella)

“highways” along which the organelles travel Microtubule roads are dynamic. Assembled at one end

while being disassembled at the other.

Microfilaments: twisted double chain of actin subunits

Function: to bear tension,

resists pulling tensions within cell

(prevents cell from collapsing)

motility (cell movement) and shape,

and simply holding the cell together.

Intermediate Filaments: interwoven, rope-strands

built from a family of proteins

called keratins.

Function: Strength, maintain shape, fix organelle location.

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microfilament (actin)

microtubule (tubulin)

nuclei

Cytoskeleton

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Cytoskeleton

Intermediate filaments

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Microtubules

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Centrioles Cell division

in animal cells, a pair of centriolesorganize microtubules

spindle fibers

Microtubules guide chromosomes in mitosisand keep the cell from collapsing

http://www.youtube.com/watch?v=VGV3fv-uZYI

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Centriole

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Cilia & Flagella – composed of microtubules

“9 + 2” tubulin pattern

(9 outer doublets, 2 microtubules in center)

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Cilia & Flagella – composed of microtubules

“9 + 2” tubulin pattern

(9 outer doublets, 2 microtubules in center)

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MovementCilia & Flagella differ in their beating patterns.

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Microfilaments

http://www.youtube.com/watch?v=Ch3izZOUjDs

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Microfilaments

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Intermediate Filaments

primary role is to provide

physical strength to cells and

tissues

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Summary http://www.youtube.com/watch?v=-bDg4gMYpsI&feature=related

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Cell Wall

Maintains shape and size of plant cell;

prevents enlargement.

Animal cells lack a cell wall,

but have cytoskeleton and…

Plays important roles in the absorption,

transport and secretion of substances.

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Extracellular Matrix (ECM)

adhesion

movement

regulation

support

Major components: glycoproteins secreted by the cells;

Collagen – most abundant glycoprotein in ECM

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Extracellular Matrix Connects intra- and extra-cellular environments