GENERAL HISTOLOGY

Detailed explanation-1: -2.1 MTs. Microtubules are polymers of the globular proteins and -tubulin dimers. The tubulin dimers polymerize head to tail into polarized protofilaments. Approximately 13 parallel protofilaments arrange in a staggered manner to form a hollow tube of 25 nm in diameter [5*].

Detailed explanation-2: -Whereas actin filaments and microtubules are polymers of single types of proteins (actin and tubulin, respectively), intermediate filaments are composed of a variety of proteins that are expressed in different types of cells.

Detailed explanation-3: -Cytoskeletal proteins are proteins that make up the cytoskeleton, flagella or cilia of cells. Generally, cytoskeletal proteins are polymers, and include tubulin (the protein component of microtubules), actin (the component of microfilaments) and lamin (the component of intermediate filaments.

Detailed explanation-4: -Eukaryotes have the most complex cytoskeletons, comprising three cytoskeletal polymers-actin filaments, intermediate filaments, and microtubules-acted on by three families of motor proteins (myosin, kinesin, and dynein).

Detailed explanation-5: -The cytoskeleton of eukaryotic cells is made of filamentous proteins, and it provides mechanical support to the cell and its cytoplasmic constituents. All cytoskeletons consist of three major classes of elements that differ in size and in protein composition.