Structure and function of cytoskeleton - One Line Questions

1. What is the diameter range of actin filaments (microfilaments)? — 7-10 nm
2. What is the typical diameter of a microtubule? — 25 nm
3. Which protein is the major component of microtubules? — Tubulin
4. Which cytoskeletal component is known for its tensile strength and ability to withstand mechanical stress? — Intermediate filaments
5. Which cytoskeletal component provides tracks for motor proteins like kinesin and dynein to transport organelles and vesicles? — Microtubules
6. The nuclear lamina, a meshwork lining the inner nuclear membrane, is composed of which type of cytoskeletal filament? — Intermediate filaments (lamins)
7. Which component of the cytoskeleton is crucial for the formation of cell-cell junctions like desmosomes and hemidesmosomes? — Intermediate filaments
8. The centrosome, a major microtubule-organizing center (MTOC) in animal cells, contains: — Centrioles and pericentriolar material
9. What are the three main types of cytoskeletal filaments? — Actin filaments, intermediate filaments, and microtubules
10. Microtubules are hollow cylinders formed from protofilaments, which are linear arrays of: — Tubulin heterodimers
11. Which protein nucleates the formation of microtubules, often found in the centrosome? — Gamma-tubulin
12. What are the two main types of tubulin subunits that form a tubulin heterodimer? — Alpha-tubulin and Beta-tubulin
13. Cilia and flagella are motile structures built upon a core arrangement of microtubules known as a: — Axoneme (9+2 arrangement)
14. Actin filaments are dynamic structures involved in various cellular processes. Which of the following is NOT a primary role of actin filaments? — Formation of the mitotic spindle
15. The '9+2' arrangement of microtubules is characteristic of: — Cilia and flagella
16. The drug cytochalasin B inhibits actin polymerization. What effect would this have on a cell? — Inhibition of cell crawling and cytokinesis
17. Which motor protein moves towards the plus end of microtubules, typically carrying cargo away from the cell center? — Kinesin
18. Which of the following is the primary function of the cytoskeleton? — Maintaining cell shape and providing mechanical support
19. What is the primary function of intermediate filaments in epithelial cells? — Providing structural integrity and resisting shearing forces
20. What is the term for the dynamic process where actin filaments grow and shrink, often occurring at opposite ends? — Treadmilling
21. The drug colchicine binds to tubulin and inhibits microtubule polymerization. What would be a likely effect on a cell? — Failure of the mitotic spindle to form, arresting cells in mitosis
22. Taxol (paclitaxel) stabilizes microtubules, preventing their depolymerization. How does this affect cell division? — It prevents the disassembly of the mitotic spindle, arresting cells in mitosis
23. Intermediate filaments are a diverse group of proteins. Which of the following is NOT an example of an intermediate filament protein? — Alpha-tubulin
24. Which motor protein moves towards the minus end of microtubules, typically carrying cargo towards the cell center? — Dynein
25. Which cytoskeletal component is primarily composed of the protein actin? — Actin filaments (microfilaments)
26. Which cellular structure is essential for maintaining the shape of the red blood cell and is composed of spectrin, an actin-binding protein? — A spectrin-actin network
27. The formation of the contractile ring during cytokinesis in animal cells is mediated by: — Actin filaments and myosin
28. Which cytoskeletal element is primarily responsible for forming the stress fibers observed in cultured fibroblasts? — Actin filaments
29. The protein spectrin is essential for maintaining the biconcave shape of red blood cells by linking actin filaments to: — The plasma membrane
30. The cellular process of phagocytosis involves the extension of pseudopods, which are driven by the dynamic assembly of: — Actin filaments
31. Which cytoskeletal component is primarily responsible for the formation and maintenance of the cell cortex, a layer just beneath the plasma membrane? — Actin filaments
32. The dynamic assembly and disassembly of the microtubule network is critical for: — Intracellular transport and chromosome segregation
33. Neurofilaments are intermediate filaments that provide structural support to: — Neuronal axons
34. Coordinated movement of cilia and flagella relies on the sliding of microtubule doublets past each other, powered by: — Dynein arms
35. Which type of myosin is primarily involved in muscle contraction? — Myosin II
36. Desmin is an intermediate filament protein found primarily in: — Muscle cells
37. Keratins are a major class of intermediate filaments found in: — Epithelial cells
38. The protein tropomyosin is associated with actin filaments and plays a role in: — Regulating muscle contraction by blocking myosin binding sites
39. Which of the following is a function of actin filaments in non-muscle cells? — Mediating cytokinesis and cell migration
40. Which of the following is a key role of microtubules in maintaining cell polarity? — Providing tracks for directed organelle movement
41. The disruption of intermediate filaments can lead to increased susceptibility of cells to mechanical stress. This is because they provide: — Resistance to tensile forces
42. Intermediate filaments are formed by the assembly of fibrous subunits into ropelike structures. What is a key characteristic of their assembly? — Does not require ATP or GTP for assembly
43. Myosin is a motor protein that interacts with actin filaments. What is its primary function? — Generating force for muscle contraction and cell movement
44. Microtubule polymerization is a polarized process. Which end typically grows faster? — The beta-tubulin end (plus end)
45. The dynamic instability of microtubules refers to their rapid switching between periods of growth and shrinkage. This is primarily driven by: — The hydrolysis of GTP to GDP within tubulin subunits
46. Microtubules play a crucial role in cell division by forming which structure? — The mitotic spindle
47. Which end of an actin filament typically shows faster polymerization (growth)? — The barbed end
48. Which of the following is a characteristic of intermediate filament proteins? — They form a central, stable network within the cytoplasm
49. Which protein is responsible for capping the plus end of actin filaments, preventing further polymerization? — CapZ
50. The polymerization of actin monomers (G-actin) into filaments (F-actin) is known as: — Actin polymerization
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