33 Questions
What are the filamentous structures comprising the cytoskeleton?
Microtubules, Microfilaments, Intermediate filaments
What is the function of cytoskeleton in eukaryotic cells?
Regulates structural support, intracellular transport, separation of chromosomes during mitosis
What is the nature of the cytoplasmic network system in the cytoskeleton?
Dynamic structure composed of protein filaments and tubules
What is the diameter of microtubules?
25 nm
Where are stable microtubules found?
Cilia, flagella, centrioles, and basal bodies
What is the role of GTP in regulating microtubule polymerization?
GTP-bound dimers are added to the plus end and hydrolyzed shortly after polymerization
What is the function of cytoplasmic microtubules?
Intracellular transport, organelle stability, mitotic spindle formation, and cellular structure production
Which drugs affect microtubule polymerization and spindle formation?
Colchicine, vincristine, and taxol
What is the role of kinesin and dynein?
Transport cytoplasmic vesicles and involved in ciliary movement
What is the structural similarity between kinesin and myosin head domains?
Both have similar head domains
What is the molecular weight of dynein?
2000 kd
What is the role of the centrosome?
Microtubule organizing center, determining intracellular organization of microtubules and initiating their assembly
Where are centrosomes located?
Near the nucleus
What is the function of centrosomes?
Significant role in microtubule assembly and determining intracellular organization of microtubules
What are the protofilaments in the wall of microtubules made of?
Tubulin
What is the function of microtubules in the cytoskeleton?
Providing structural support and facilitating intracellular transport
What is the role of intermediate filaments in the cytoskeleton?
Contributing to the maintenance and preservation of cell shape
How does the cytoskeleton contribute to the separation of chromosomes during mitosis?
Providing structural support for the chromosomes
What is the main function of the cytoskeleton in eukaryotic cells?
Structural support, intracellular transport, separation of chromosomes during mitosis
Which filamentous structure is involved in cell movement and forms flagella or cilia?
Microtubules
What is the nature of the cytoplasmic network system in the cytoskeleton?
Dynamic structure continually reorganized as cells move and change shape
What is the diameter of microtubules?
25 nm
What is the role of GTP in regulating microtubule polymerization?
GTP-bound dimers are added to the plus end and hydrolyzed shortly after polymerization
Where are stable microtubules found?
Cilia, flagella, centrioles, and basal bodies
What is the function of microtubules in the cytoskeleton?
Intracellular transport, organelle stability, mitotic spindle formation, and cellular structure production
Which drugs affect microtubule polymerization and spindle formation?
Colchicine, vincristine, and taxol
What is the role of kinesin and dynein?
Transport cytoplasmic vesicles and involved in ciliary movement
What is the nature of the cytoplasmic network system in the cytoskeleton?
Dynamic and undergoes cycles of growth and shrinkage
What are the protofilaments in the wall of microtubules made of?
Tubulin
What is the role of intermediate filaments in the cytoskeleton?
Anchor the nucleus and other organelles in place
What is the function of the centrosome?
Determining the intracellular organization of microtubules and initiating their assembly
What is the structural similarity between kinesin and myosin head domains?
Both have ATP-binding sites
What is the molecular weight of dynein?
2000 kd
Study Notes
Microtubules: Key Structures and Functions
- Microtubules are hollow tubes made of the protein tubulin, with a diameter of 25 nm and consisting of 13 protofilaments in its wall.
- They can be divided into stable (found in cilia, flagella, centrioles, and basal bodies) and labile (found in cytoplasmic microtubules and the mitotic spindle) microtubules.
- Microtubules are polar structures with fast-growing (+) ends and slow-growing (-) ends, important for determining the direction of movement along them.
- GTP plays a role in regulating microtubule polymerization, with GTP-bound dimers added to the plus end and hydrolyzed shortly after polymerization.
- Microtubules undergo dynamic instability, alternating between cycles of growth and shrinkage, regulated by Microtubule Associated Proteins (MAPs).
- Cytoplasmic microtubules play roles in intracellular transport, organelle stability, mitotic spindle formation, and cellular structure production.
- Drugs like colchicine, vincristine, and taxol bind to tubulin, affecting microtubule polymerization and spindle formation.
- Microtubule motor proteins, such as kinesin and dynein, transport cytoplasmic vesicles and are involved in ciliary movement, with ATP as a receptor for motor proteins.
- Kinesin and myosin head domains are structurally similar, and different tail sequences move different cargo types.
- Dynein, a 2000 kd protein, interacts with tubulin, moves along microtubules toward minus ends, and results in bending.
- The centrosome serves as the microtubule organizing center, determining the intracellular organization of microtubules and initiating their assembly.
- Centrosomes are located near the nucleus, play a significant role in microtubule assembly, and have a fundamental role in determining the intracellular organization of microtubules.
Microtubules: Key Structures and Functions
- Microtubules are hollow tubes made of the protein tubulin, with a diameter of 25 nm and consisting of 13 protofilaments in its wall.
- They can be divided into stable (found in cilia, flagella, centrioles, and basal bodies) and labile (found in cytoplasmic microtubules and the mitotic spindle) microtubules.
- Microtubules are polar structures with fast-growing (+) ends and slow-growing (-) ends, important for determining the direction of movement along them.
- GTP plays a role in regulating microtubule polymerization, with GTP-bound dimers added to the plus end and hydrolyzed shortly after polymerization.
- Microtubules undergo dynamic instability, alternating between cycles of growth and shrinkage, regulated by Microtubule Associated Proteins (MAPs).
- Cytoplasmic microtubules play roles in intracellular transport, organelle stability, mitotic spindle formation, and cellular structure production.
- Drugs like colchicine, vincristine, and taxol bind to tubulin, affecting microtubule polymerization and spindle formation.
- Microtubule motor proteins, such as kinesin and dynein, transport cytoplasmic vesicles and are involved in ciliary movement, with ATP as a receptor for motor proteins.
- Kinesin and myosin head domains are structurally similar, and different tail sequences move different cargo types.
- Dynein, a 2000 kd protein, interacts with tubulin, moves along microtubules toward minus ends, and results in bending.
- The centrosome serves as the microtubule organizing center, determining the intracellular organization of microtubules and initiating their assembly.
- Centrosomes are located near the nucleus, play a significant role in microtubule assembly, and have a fundamental role in determining the intracellular organization of microtubules.
Test your knowledge of microtubules with this quiz on their structures and functions. Explore their role in cellular movement, intracellular transport, and spindle formation, as well as their interaction with drugs and motor proteins. Brush up on key concepts such as dynamic instability, GTP regulation, and the role of centrosomes in microtubule organization.
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