Dictionary: Journal Post 9

The following terms are from Chapter 12 which deals with the cytoskeleton and cellular movement. I chose these terms because I wanted to have a better understanding of their structure and roles in the cell.

Actin is a protein that forms microfilaments. It is also a main component in the structure of the cytoskeleton. One particular function it has in cellular movement is in muscular contraction where it interacts with filaments of myosin, another protein used in muscle contraction. Actin filaments are typically small, thin filaments and contain polarity. The monomers in actin are added at a rate that is proportional to concentration. This is characterized by the term critical concentration where the rate of polymerization equals the rate of dissociation. Actin can be organized in multiple ways, which include bundled or network organization.

Intermediate Filaments are the second of the three cytoskeletal filaments. They help provide mechanical support for the plasma membrane as well as function with other filaments in the cytoskeleton. They provide tension and resist stretching which keeps the shape of the cytoskeleton. These filaments do not contain polarity. Vimetin and Desmin are some intermediate filaments which help to form the cytoskeleton.

Microtubules are a filamentous structure which are important for their role in cellular movement. They also play a role in cellular division, the cytoskeleton, and intracellular transport. Microtubules are formed by tubulin. Tubulin heterdimers assemble into protofilaments and then to microtubules. Microtubules also place organelles in the cytoplasm.









For more information, the following websites can be visited.

Microtubules
Actin
Intermediate Filaments