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Today, the class’ objective was to finish the notes of the remaining organelles which consisted of the cytoskeleton. The teacher intricately discussed the three major protein fibers, microtubules, microfilaments, and intermediate filaments and the class analyzed the structure and the function of these different fibers.
Firstly, the class went over the details of microtubules, which are the thickest of the three fibers, measuring at about 25nm. They are also composed of protein tubulin. They are significant because they are responsible for a cell’s structure and a cell’s movement. They also move chromosomes during cell division with the use of centrioles, which organizes microtubules by guiding these chromosomes. Microtubules are also are able to move through the use of cilia and flagella. Although cilia and flagella both create movement, they function in very disparate ways. For example, cilia moves with an oar-like movement with alternating power and recovery strokes. Flagella has an undulatory movement and it allows small organisms to propel themselves through water. Also, it its important to know that the bending of cilia and flagella is a result of motor proteins such as dynein.
Another similar structure to the microtubules are the intermediate filaments which are quite smaller measuring about 8-12nm. These filaments are built from keratin proteins. Some of their functions are that they are specialized for bearing tension, and they are able to holding things in place within cells.They also reinforce the shape of the cell and they fix the organelle locations. Last of the main protein fibers are the microfilaments which are about 7nm in diameter, making them the thinnest of the three. They are often referred to as actin filaments because they consist of twisted double chains of actin subunits. They are quite essential in muscles cells and by interacting with myosin filaments, the actin filaments create muscle contraction. Actin filaments also constantly form and dissolve which makes the cytoplasm liquid or stiff during movement.
Lastly, the class watched a video that concerned the functions and the actions that occur within a cell. This video elaboarate on the true structre and movement of these organelles within cells and what functions they perform within the body. This really helped to piece together and eplain how sophicated a cell really is with the use of a visual aid.
Today in class you investigated the use of steroids in today’s society. After reading the article in the textbook on p 308 entitled “Athletes Looking Good and Doing Better with Anabolic Steroids?” You were asked to research steroids affects on the human body, in particular their use in high school athletics. Please write a blog post at the 
