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6.8. The cytoskeleton

Cytoskeleton

The cytoskeleton is made up of a network of protein filaments that extends throughout the interior of the cell to the interior of the plasma membrane. It is not a permanent structure, but a dynamic one, continually breaking down and rebuilding according to cellular needs.

It is unique to eukaryotic cells, but prokaryotes are currently known to have another similar cytoskeleton.

The cytoskeleton is made up of:

These filaments appear associated with other proteins, originating more complex structures, allowing cell movements, such as muscle contraction, produced by actin filaments, and the movement of cilia and flagella, which depend on microtubules.

Questions that have come out in University entrance exams (Selectividad, EBAU, EvAU)

Aragon. September 2010, option B. 5.

Explain what the cytoskeleton is and what it does. (1 point)

Aragon. September 2003, option A, part A. Question 4 .- (2 points).

Explain:

b) What are the cilia like? Name two other cell structures that are made up of the cytoskeleton. (1 point)

Madrid, September 2017, option A, question 2.

In relation to various structures that we can find in eukaryotic cells:

a) List the three elements that make up the cytoskeleton and the fundamental proteins that make them up (0.75 points)

Murcia, June 2018, option A, question 2.

Regarding the cell:

a) What is the cytoskeleton? (0.2 points).
b) In what type of cells does it occur? (0.15 points).
c) What are the most notable constituents of the cytoskeleton and what functions do they perform? (0.85 points).
d) Indicate the main functions of the centrosome? (0.3 points).

Madrid, June 2021, question A4

A.4.- With reference to the cell's cytoskeleton:

a) Indicate the element of the cytoskeleton that is related to each of the following statements (1 point):

1. Creation of structures such as centrioles.
2. Contractile movement of muscle cells, formation of pseudopods, formation of microvilli in intestinal cells.
3. Cylindrical and hollow structures formed by protofilaments made up of protein dimers.
4. Keratin filaments in epithelial cells and neurofilaments in neurons.

b) Briefly describe the internal structure of the stem or axoneme of the cilia and flagella (0.5 points).

c) Name the main difference between cilia and flagella. Indicate whether cilia are present in all plant and animal cells (0.5 points).