Table of Contents
What kind of protein do microtubules or microfilaments?
Microfilaments can also carry out cellular movements including gliding, contraction, and cytokinesis. Microtubules are cylindrical tubes, 20-25 nm in diameter. They are composed of subunits of the protein tubulin–these subunits are termed alpha and beta.
How are microtubules assembled?
Microtubules assemble by polymerization of αβ-tubulin dimers. Once microtubules have assembled, their stability is temperature-dependent. For instance, if microtubules are cooled to 4 °C, they depolymerize into stable αβ-tubulin dimers (Figure 19-9a).
Are microtubules protein fibers?
In eukaryotes, there are three types of protein fibers in the cytoskeleton: microfilaments, intermediate filaments, and microtubules.
What do protein dimers assemble into?
Inside The Cell
| Question | Answer |
|---|---|
| Many cell organelles, most notably the nucleus, are anchored by __________ which are assembled from a diverse class of proteins. | Intermediate filaments |
| Centrosomes are sites where proteins assembles dimers into ______________. | microtubules |
What macromolecule is in microtubules?
tubulin
Microtubules are biopolymers that are composed of subunits made from an abundant globular cytoplasmic protein known as tubulin, as illustrated in Figure 1.
How do microtubules act as a cytoskeleton?
With a diameter of about 25 nm, microtubules are the widest components of the cytoskeleton. They help the cell resist compression, provide a track along which vesicles move through the cell, and pull replicated chromosomes to opposite ends of a dividing cell.
Which of the following is not composed of microtubules?
Cilia and spindle fibers are both composed of microtubules. Prokaryotes do not contain developed microtubules.
Are microtubules made of actin?
Microtubules are the largest type of filament, with a diameter of about 25 nanometers (nm), and they are composed of a protein called tubulin. Actin filaments are the smallest type, with a diameter of only about 6 nm, and they are made of a protein called actin.
What interferes with the assembly of microtubules?
A mitotic inhibitor is a drug that inhibits mitosis, or cell division. These drugs disrupt microtubules, which are structures that pull the chromosomes apart when a cell divides. Mitotic inhibitors interfere with the assembly and disassembly of tubulin into microtubule polymers.
Where are cytoskeletal proteins made?
However, these chemicals are manufactured in the cell body. It is the job of transport proteins to walk vesicles filled with these chemicals down the microtubule highway to the terminal where they are needed.
Where is protein synthesized in cell?
Ribosomes
Ribosomes are the sites in a cell in which protein synthesis takes place.