Ingenuity Honor’s Biology December 6th, Thursday Baltimore Polytechnic Institute Ingenuity Honor’s Biology December 6th, Thursday Unit 3: Cells; Cytoskeleton and cell movement Insong James Lee, Ph.D.

Unit 3: Cells; Cytoskeleton and cell movement December 6th, Thursday Learning objectives: • What is the role of microfilaments in the cell? What is the role of microtubules in the cell? What are some ways that cell move? Unit 3: Cells; Cytoskeleton and cell movement

Unit 3: Cells; cytoskeleton and cell movement Topic slides Overview of cytoskeleton 4-5 Microfilament 6-8 Microtubule 9-15 Cell movement 16-23

Overview of cytoskeleton slide 5

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

Microfilament slides 7-8

Microfilaments are the smallest strands of the cytoskeleton

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

microtubules slides 9-14

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)

Cell movement slides 16-22

Movement Some cells move using structures 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….