Cytoskeleton 2 Microtubules & Intermediate Filaments

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What is the tubulin subunit composed of in microtubules?

An alpha-tubulin and a beta-tubulin (correct)

An alpha-tubulin and a gamma-tubulin

Two alpha-tubulins

Two beta-tubulins

What happens to the GTP molecule bound to alpha-tubulin in microtubules?

It is trapped and never hydrolyzed or exchanged (correct)

It is exchanged with GDP during polymerization

It is hydrolyzed during depolymerization

It is involved in recruiting microtubule-associated proteins

What is the consequence of GDP exchange with GTP in microtubules during depolymerization?

Microtubules shrink

Microtubules grow (correct)

New microtubules are nucleated

Microtubules stay stable

Which structural component forms the hollow cylindrical structure of microtubules?

Protofilaments Signup and view all the answers

What is the primary function of microtubules in cells?

Provide mechanical stability to the cell Signup and view all the answers

How are microtubules affected by drugs like colchicine or paclitaxel?

Inducing depolymerization Signup and view all the answers

What is dynamic instability in microtubules?

The coexistence of assembly and disassembly at the ends of a microtubule Signup and view all the answers

What happens when GTP hydrolysis proceeds more rapidly than the addition of new subunits to a microtubule?

The microtubule begins to depolymerize (shrink) Signup and view all the answers

What is the role of kinesin in relation to microtubules?

Travels towards the (+) end of microtubules Signup and view all the answers

Which statement about dynein is correct?

Composed of two identical heavy chains and transports cargo towards the (-) end of microtubules Signup and view all the answers

Which activity occurs in the globular head domains of kinesin?

ATP hydrolysis Signup and view all the answers

What is the clinical relevance of microtubules dynamic instability?

Regulating cell growth, movement, and cell signaling events Signup and view all the answers

What is the major structural role of microtubules in eukaryotic cells?

Formation of cilia and flagella Signup and view all the answers

What is responsible for aligning and segregating chromosomes during cell division?

Astral microtubuli Signup and view all the answers

How do cilia and flagella move?

Dynein motor proteins bend microtubules Signup and view all the answers

What is the difference between prokaryotic and eukaryotic flagella?

Prokaryotic flagella are structurally different and lack microtubule-based structures Signup and view all the answers

What structures are responsible for moving cells in an aqueous environment?

Flagella Signup and view all the answers

What can cilia do in terms of moving fluid around a cell?

Move fluid around the cell Signup and view all the answers

What is the primary function of intermediate filaments in cells?

Strengthening cells and epithelia Signup and view all the answers

Which drug binds irreversibly to microtubules and spindle proteins, interfering with the formation of the mitotic spindle in tumor cells?

Vincristine Signup and view all the answers

What is the role of colchicine in familial Shar-pei fever treatment?

Prevents polymerization of microtubules Signup and view all the answers

Which structure forms a protective cage for the cell's DNA by lining the inner face of the nuclear envelope?

Intermediate filaments Signup and view all the answers

What effect does paclitaxel have on microtubules in cells?

Increases dynamic nature Signup and view all the answers

Which type of cells do intermediate filaments help extend long and robust axons?

Nerve cells Signup and view all the answers

What is the major microtubule organizing center (MTOC) in animal cells?

Centrosome Signup and view all the answers

Which cellular structure is composed of two cylinders called centrioles?

Centrosome Signup and view all the answers

What is the function of MAPs (Microtubule-Associated Proteins) in cells?

Vesicle and organelle movement Signup and view all the answers

What does the term 'cell polarity' refer to?

Spatial differences in shape, structure, and function within a cell Signup and view all the answers

Where do microtubules originate from in a cell?

Centrosome Signup and view all the answers

How many amino acids long are each of the closely related globular proteins forming the tubulin subunit in microtubules?

445-450 amino acids Signup and view all the answers

What happens to the GTP molecule bound to beta-tubulin during microtubule depolymerization?

It is exchanged to GDP Signup and view all the answers

How are microtubules formed structurally?

Hollow cylindrical structures Signup and view all the answers

What is the process called when microtubules grow by adding new subunits?

Polymerization Signup and view all the answers

Which component of the tubulin heterodimer has a binding site for GTP that is not hydrolyzed or exchanged?

Alpha-tubulin Signup and view all the answers

What is the structural arrangement of alpha-beta tubulin heterodimers in microtubules?

Head to tail Signup and view all the answers

What is the primary function of intermediate filaments in cells?

Provide mechanical stability to cells and tissues Signup and view all the answers

How does vincristine affect tumor cells?

Arrests tumor cells in metaphase Signup and view all the answers

Which component forms the hollow cylindrical structure of microtubules?

Tubulin subunits Signup and view all the answers

What is the role of colchicine in relation to microtubules?

Prevents polymerization of microtubules Signup and view all the answers

What effect does paclitaxel have on microtubules in cells?

Increases dynamic nature of microtubules Signup and view all the answers

What is the major structural role of microtubules in eukaryotic cells?

Assist in chromosome alignment during division Signup and view all the answers

What is the main structural role of microtubules in eukaryotic cells?

Providing specialized motility structures like cilia Signup and view all the answers

In prokaryotes, how do flagella structurally differ from eukaryotic flagella?

Prokaryotic flagella do not contain any microtubule-based structures Signup and view all the answers

What is the role of the dynein motor proteins in cilia and flagella movement?

Allowing bending and generating force for movement Signup and view all the answers

Which cells use flagella to move in an aqueous environment?

Spermatozoids Signup and view all the answers

What occurs when a cell divides concerning microtubules?

Microtubules rearrange to form a bipolar mitotic spindle Signup and view all the answers

What is the function of cilia concerning fluid movement around a cell?

Moving fluid around the cell Signup and view all the answers

What is the primary role of microtubules in transporting intracellular cargoes?

Transporting vesicles, organelles, and protein complexes Signup and view all the answers

Which cellular structure is considered as the major microtubule organizing center (MTOC) in animal cells?

Centrosome Signup and view all the answers

What are centrioles and where are they typically located in animal cells?

Tiny cylindrical structures near the nucleus, participating in spindle fiber development Signup and view all the answers

What is the term for spatial differences in shape, structure, and function within a cell?

Cell polarity Signup and view all the answers

Which cellular components read Microtubule-Associated Proteins (MAPs) to facilitate organelle and vesicle movement?

Microtubule motors Signup and view all the answers

Where do microtubules originate from within a cell?

Microtubule organizing center (MTOC) Signup and view all the answers

What is the central building block of intermediate filaments?

Coiled-coil dimer Signup and view all the answers

Which family of intermediate filaments is primarily produced by keratinocytes in the epidermis?

Epithelial keratin filaments Signup and view all the answers

What is the clinical utility of the diversity of keratins in epithelial cancers?

Guiding treatment choices Signup and view all the answers

Which intermediate filament type provides mechanical stability to the cell nucleus?

Desmin Signup and view all the answers

What is the primary function of neurofilaments in cells?

Contribute to axonal growth and stability Signup and view all the answers

Which type of intermediate filament is primarily responsible for maintaining cell shape and integrity?

Vimentin filaments Signup and view all the answers

What does dynamic instability in microtubules refer to?

The simultaneous assembly and disassembly at the microtubule ends Signup and view all the answers

What happens if GTP hydrolysis occurs more rapidly than the addition of new subunits to a microtubule?

The microtubule starts to depolymerize Signup and view all the answers

Which domain of tubulin dimer is responsible for GTP hydrolysis in microtubules?

Beta-subunit Signup and view all the answers

What is the structural plasticity and dynamics of microtubules dependent on?

GTP-binding domain of beta-tubulin Signup and view all the answers

Which protein travels towards the positive end of the microtubule?

Kinesin Signup and view all the answers

What is the clinical relevance of the dynamic instability of microtubules?

Regulating cell growth and movement Signup and view all the answers

What is the function of paclitaxel (Taxol) in anticancer chemotherapy?

Prevents progression of mitotic cells to G1 phase Signup and view all the answers

Which drug binds irreversibly to microtubules and spindle proteins, interfering with mitotic spindle formation in tumor cells?

Vincristine Signup and view all the answers

How does colchicine aid in familial Shar-pei fever treatment?

Prevents polymerization of microtubules Signup and view all the answers

Which statement accurately describes intermediate filaments?

Have a polarity (+ or - end) Signup and view all the answers

What is the role of intermediate filaments in cell structure?

Strengthen cells and epithelia Signup and view all the answers

Which protein forms a protective cage for a cell's DNA by lining the nuclear envelope?

Lamin Signup and view all the answers

What cellular component is responsible for the selective stabilization of microtubules, allowing for cell polarization?

MAPs Signup and view all the answers

What is the major microtubule organizing center (MTOC) in animal cells?

Centrosome Signup and view all the answers

What is the function of microtubule motors in relation to MAPs?

Read and transport organelles based on MAPs Signup and view all the answers

What is the specific function of centrioles in animal cells?

Developing spindle fibers during cell division Signup and view all the answers

Which cellular structure is composed of two cylinders called centrioles?

Centrosome Signup and view all the answers

What is the primary role of MAPs in intracellular transport?

Move vesicles and organelles along microtubules Signup and view all the answers

What is the structural role of microtubules in cilia and flagella?

Serve as the major component responsible for motility structures Signup and view all the answers

What is the primary function of the dynein motor proteins in cilium and flagellum movement?

Generating force for bending microtubules Signup and view all the answers

How do prokaryotic flagella differ structurally from eukaryotic flagella?

Completely different structure from eukaryotic flagella Signup and view all the answers

What is the main function of epithelial keratin filaments in cells?

Anchor epithelial cells via desmosomes/hemidesmosomes Signup and view all the answers

What clinical utility can be derived from the diversity of keratins in epithelial cancers?

Diagnosis of the epithelial tissue in which cancer originated Signup and view all the answers

Which type of intermediate filaments is essential for scaffold function in sarcomeres of skeletal and cardiac muscle?

Desmin Signup and view all the answers

What is the primary role of neurofilaments within cells?

Participating in axonal growth in neurons Signup and view all the answers

In what specific diseases do mutations in keratin genes lead to disruption of the normal keratin network in skin cells?

Blistering diseases like epidermolysis bullosa simplex (EBS) Signup and view all the answers

What is the major structural role of lamin within a cell?

Mechanical stability of the cell nucleus Signup and view all the answers

Cytoskeleton 2 Microtubules & Intermediate Filaments

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Questions and Answers

What is the tubulin subunit composed of in microtubules?

What happens to the GTP molecule bound to alpha-tubulin in microtubules?

What is the consequence of GDP exchange with GTP in microtubules during depolymerization?

Which structural component forms the hollow cylindrical structure of microtubules?

What is the primary function of microtubules in cells?

How are microtubules affected by drugs like colchicine or paclitaxel?

What is dynamic instability in microtubules?

What happens when GTP hydrolysis proceeds more rapidly than the addition of new subunits to a microtubule?

What is the role of kinesin in relation to microtubules?

Which statement about dynein is correct?

Which activity occurs in the globular head domains of kinesin?

What is the clinical relevance of microtubules dynamic instability?

What is the major structural role of microtubules in eukaryotic cells?

What is responsible for aligning and segregating chromosomes during cell division?

How do cilia and flagella move?

What is the difference between prokaryotic and eukaryotic flagella?

What structures are responsible for moving cells in an aqueous environment?

What can cilia do in terms of moving fluid around a cell?

What is the primary function of intermediate filaments in cells?

Which drug binds irreversibly to microtubules and spindle proteins, interfering with the formation of the mitotic spindle in tumor cells?

What is the role of colchicine in familial Shar-pei fever treatment?

Which structure forms a protective cage for the cell's DNA by lining the inner face of the nuclear envelope?

What effect does paclitaxel have on microtubules in cells?

Which type of cells do intermediate filaments help extend long and robust axons?

What is the major microtubule organizing center (MTOC) in animal cells?

Which cellular structure is composed of two cylinders called centrioles?

What is the function of MAPs (Microtubule-Associated Proteins) in cells?

What does the term 'cell polarity' refer to?

Where do microtubules originate from in a cell?

How many amino acids long are each of the closely related globular proteins forming the tubulin subunit in microtubules?

What happens to the GTP molecule bound to beta-tubulin during microtubule depolymerization?

How are microtubules formed structurally?

What is the process called when microtubules grow by adding new subunits?

Which component of the tubulin heterodimer has a binding site for GTP that is not hydrolyzed or exchanged?

What is the structural arrangement of alpha-beta tubulin heterodimers in microtubules?

What is the primary function of intermediate filaments in cells?

How does vincristine affect tumor cells?

Which component forms the hollow cylindrical structure of microtubules?

What is the role of colchicine in relation to microtubules?

What effect does paclitaxel have on microtubules in cells?

What is the major structural role of microtubules in eukaryotic cells?

What is the main structural role of microtubules in eukaryotic cells?

In prokaryotes, how do flagella structurally differ from eukaryotic flagella?

What is the role of the dynein motor proteins in cilia and flagella movement?

Which cells use flagella to move in an aqueous environment?

What occurs when a cell divides concerning microtubules?

What is the function of cilia concerning fluid movement around a cell?

What is the primary role of microtubules in transporting intracellular cargoes?

Which cellular structure is considered as the major microtubule organizing center (MTOC) in animal cells?

What are centrioles and where are they typically located in animal cells?

What is the term for spatial differences in shape, structure, and function within a cell?

Which cellular components read Microtubule-Associated Proteins (MAPs) to facilitate organelle and vesicle movement?

Where do microtubules originate from within a cell?

What is the central building block of intermediate filaments?

Which family of intermediate filaments is primarily produced by keratinocytes in the epidermis?

What is the clinical utility of the diversity of keratins in epithelial cancers?

Which intermediate filament type provides mechanical stability to the cell nucleus?

What is the primary function of neurofilaments in cells?

Which type of intermediate filament is primarily responsible for maintaining cell shape and integrity?

What does dynamic instability in microtubules refer to?

What happens if GTP hydrolysis occurs more rapidly than the addition of new subunits to a microtubule?

Which domain of tubulin dimer is responsible for GTP hydrolysis in microtubules?

What is the structural plasticity and dynamics of microtubules dependent on?

Which protein travels towards the positive end of the microtubule?

What is the clinical relevance of the dynamic instability of microtubules?

What is the function of paclitaxel (Taxol) in anticancer chemotherapy?

Which drug binds irreversibly to microtubules and spindle proteins, interfering with mitotic spindle formation in tumor cells?

How does colchicine aid in familial Shar-pei fever treatment?

Which statement accurately describes intermediate filaments?

What is the role of intermediate filaments in cell structure?

Which protein forms a protective cage for a cell's DNA by lining the nuclear envelope?

What cellular component is responsible for the selective stabilization of microtubules, allowing for cell polarization?

What is the major microtubule organizing center (MTOC) in animal cells?

What is the function of microtubule motors in relation to MAPs?

What is the specific function of centrioles in animal cells?

Which cellular structure is composed of two cylinders called centrioles?

What is the primary role of MAPs in intracellular transport?