37 Questions
What is the main function of intermediate filaments in the cytoskeleton?
Give cells mechanical strength
Which protein network in the cytoskeleton is characterised by dynamic instability?
Microtubules
What is the structure of microtubules composed of?
α- & β-tubulin dimers
Which motor proteins are responsible for positioning organelles and vesicles within a cell along microtubules?
Kinesins and dyneins
What differentiates microfilaments from intermediate filaments and microtubules in terms of their functions?
Diversity of actin binding proteins controlling polymerisation
What is the diameter of microtubules, making them the largest of the three types of cytoskeletal fibers?
About 25 nm
What are the two globular proteins that polymerize to form microtubules?
α-tubulin and β-tubulin
What is the primary function of microtubules in a dividing cell?
Pulling replicated chromosomes to opposite ends
What is the diameter of actin filaments, also known as microfilaments?
About 7 nm
Which protein serves as tracks for the movement of the motor protein myosin along actin filaments?
Actin
What is the structural arrangement of actin monomers in actin filaments that resembles a double helix?
Linked in a structure resembling a double helix
Which type of protein filaments in the cytoskeleton serve as the structural elements of flagella, cilia, and centrioles?
Microtubules
Describe the role of microtubules in cellular events requiring motion.
Microtubules provide structural support and serve as tracks for motor proteins to move organelles and vesicles within the cell.
How do actin filaments contribute to muscle contraction?
Actin and myosin filaments sliding past each other within sarcomeres allow for muscle contraction.
What distinguishes intermediate filaments from microfilaments and microtubules in terms of stability?
Intermediate filaments are more stable and do not depolymerize and reform quickly like actin filaments.
Give an example of a specific protein that makes up some types of intermediate filaments.
Keratin is an example of a specific protein found in some types of intermediate filaments.
Explain the structural difference between microtubules and intermediate filaments.
Microtubules are larger in diameter and are composed of tubulin proteins, while intermediate filaments are smaller and composed of fibrous proteins.
How do actin filaments contribute to cell motility?
Actin filaments can depolymerize and reform quickly, facilitating cell motility.
What is the specialized role of intermediate filaments in the cell?
Intermediate filaments are specialized to bear tension and maintain the shape of the cell.
How do microtubules contribute to maintaining cell shape?
Microtubules provide structural support and help maintain the overall shape of the cell.
What is the main function of Intermediate Filaments in cells?
Providing structural support and strength
Which type of cells primarily contain Vimentin and vimentin-like filaments?
Connective tissue cells
Where are Keratin filaments predominantly found in the body?
Epithelial cells
Which type of Intermediate Filament provides support to the nuclear envelope?
Lamins
Where does microtubule filament growth occur?
Plus end extending into the cytoplasm
What is the function of Microtubule filaments in a cell?
Aiding in chromosome segregation during cell division
Which part of a Microtubule consists of β-tubulin?
"Plus end"
What provides sites for chromosome attachment within a cell?
"Lamins"
What event occurs when the hydrolysis front catches up to the growing end of a microtubule?
Catastrophe event
Which protein is a key regulator of microtubule dynamics by promoting the addition of GTP to tubulin subunits?
EB1
What process is essential for the growth and stability of microtubules?
GTP hydrolysis to GDP
What is the function of the hydrolysis front in microtubule dynamics at low tubulin concentrations?
Cause catastrophe events
What is the process by which a protofilament in a microtubule can be rescued during shrinkage?
Rescue
How do stabilizing agents like paclitaxel and Tau prevent catastrophe in microtubules?
Inhibit conformational changes
What is the key role of the GTP hydrolysis state of the tubulin heterodimer in regulating microtubule stability?
Determining stability
How do remnants of GTP-tubulin, known as islands, contribute to the initiation of rescue events in microtubules?
Associated with rescue
What is the significance of the conformational change in the α-subunit of the tubulin heterodimer during GTP hydrolysis?
Destabilizes the lattice
Test your knowledge on the different protein networks that make up the cytoskeleton, including intermediate filaments like keratin and vimentin filaments, non-polar filaments, and microtubules composed of α- & β-tubulin dimers. Learn about their functions and characteristics.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
