Cytoskeleton & Movement Do Now: 11/11 (Week 12) OBJECTIVES: Describe and distinguish structures for cell movement: cilia, flagella, and pseudopodia. Describe and distinguish the structures of the cytoskeleton: actin microfilaments, tubulin microtubules, and centrioles/centrosome TASK: Pass forward week 11 Do Nows. Construct a protein production flowchart showing the cell parts and materials used.

Cytoskeleton

Cytoskeleton Just like your body has a skeleton to maintain its shape and size, cells have a cytoskeleton to do the same thing.

Microfilaments are the smallest strands of the cytoskeleton

Microfilaments are a polymer of a protein called actin. They’re used for cell movement and muscle contraction

Microtubules are larger strands and are thicker and stronger.

Microtubules are hollow tubes made of a protein called tubulin.

Centrioles Organize Cell’s Internal Space The centrioles are the cell part from which the microtubules of the cytoskeleton grow. The position of the centrioles determines the location of the nucleus, cell shape, and the location of flagella and cilia in Eukaryotic cells that have these. NOT found in: prokaryotes, most plants, fungi. Eukaryotic cell types have a tubulin network attached to different protein structures MTOC, usually around the nucleus) Prokaryotes use different cytoskeletal proteins

Cell Part: Centrosome & Centrioles FUNCTION: The centrioles (2 per centrosome) are responsible for coordinating the division of chromosomes during cell division AND organizing the cytoskeleton.

During cell division, spindle fibers move chromosomes apart During cell division, spindle fibers move chromosomes apart. Spindle fibers are microtubules.

Centriole Structure: Interesting Bio-geometry (9-triplet microtubules)

Movement Some cells move using organelles called cilia and flagella

Cilia are small hair-like structures on the outside of a cell.

If a cell has cilia, it always has a lot of them!

Cilia (and flagella) are made of microtubules bundled together Cilia (and flagella) are made of microtubules bundled together. (9 doublet + 2 single)

Flagella are much bigger than cilia, and cells that have them only have a few.

One More Way to Move: Pseudopodia Means “false foot” Think blob

How do cells move? Cilia: many tiny beating “hairs.” Flagella: a few long, whip-like propellers. Pseudopodia: flow from 1 spot to another. Do The Dance….

Movement in Animals What body systems work together to make you move? How is that similar to the cell systems we just learned about?

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