Lecture 9 Flashcards
(15 cards)
What role do microtubules play in cell division?
Microtubules form the mitotic spindle, which is essential for the separation and distribution of chromosomes during cell division.
Example sentence: Microtubules are crucial for ensuring the accurate distribution of genetic material during cell division.
Describe the composition and structure of microfilaments.
Microfilaments are composed of G-actin monomers that polymerize into F-actin, forming a double-helix structure. They are the smallest and most flexible cytoskeletal filaments.
Additional information: Microfilaments play a key role in cell shape and movement.
How are actin filaments involved in muscle contraction?
Actin filaments interact with myosin, an ATP-dependent process, which is critical for muscle contraction and movement.
Example sentence: The interaction between actin and myosin is essential for the sliding filament mechanism in muscle contraction.
Explain the role of actin in membrane transport.
Actin is involved in endocytosis and exocytosis, playing a critical role in neurons and secretory cells.
Example sentence: Actin filaments help in the movement of vesicles during the process of membrane transport.
What are intermediate filaments and how do they differ in structure from the other cytoskeletal filaments?
Intermediate filaments are 10 nm in diameter, apolar, and made from varied proteins like lamins and keratin, providing mechanical strength and resistance to compressive forces.
Additional information: Unlike microtubules and microfilaments, intermediate filaments do not have a defined polarity.
Identify the types of proteins that make up intermediate filaments.
Types of proteins include lamins, keratin, vimentin, desmin, and neurofilaments.
Example sentence: Different cell types express specific intermediate filament proteins based on their structural and functional requirements.
Discuss the function of intermediate filaments in cell junctions.
Intermediate filaments are crucial in cell junctions like desmosomes and hemidesmosomes, providing mechanical support in tissues such as epithelium and cardiac muscle.
Example sentence: Intermediate filaments help anchor cells together in tissues subjected to mechanical stress.
What function do microtubules serve in internal transport?
Microtubules facilitate axonal transport, aided by motor proteins like kinesin and dynein, critical for the transport of cellular components.
Additional information: Microtubules are essential for the movement of organelles and molecules within the cell.
Describe how microfilaments contribute to cell migration.
Microfilaments regulate cell migration by their dynamic assembly and disassembly, facilitating protrusions, adhesions, and contractile filaments.
Example sentence: The coordinated action of microfilaments is necessary for the directional movement of cells during migration.
How do actin filaments support cell extension in specific cell types?
Actin filaments support structures like microvilli and sensory stereocilia, increasing surface area in intestinal and renal cells, and aiding sensory function in inner ear cells.
Example sentence: Actin filaments play a crucial role in the specialized structures that enhance the functionality of certain cell types.
What is the structural composition of microtubules?
Microtubules are composed of ⍺-tubulin and β-tubulin, forming protofilaments that assemble into polarized microtubules with positive and negative ends.
Additional information: The dynamic instability of microtubules allows them to rapidly grow and shrink as needed in cellular processes.
How do actin filaments function in cell division?
Actin filaments form the contractile ring during cytokinesis, which is crucial for the physical separation of daughter cells.
Example sentence: Actin filaments generate the force required for the cleavage of the cell during cell division.
What is the role of microtubules in cell movement?
Microtubules form the axoneme in structures like sperm tails and cilia, essential for motility and fluid movement across epithelial surfaces.
Example sentence: The arrangement of microtubules in cilia enables coordinated beating motions for cellular movement.
Why are actin filaments essential in cell junctions?
Actin filaments are essential for forming tight and adherens junctions, which are crucial for maintaining cell-to-cell adhesion.
Example sentence: Actin filaments provide the structural integrity necessary for the stability of cell junctions.
Can you explain how intermediate filaments aid in maintaining cell shape?
Intermediate filaments provide mechanical strength to cells, helping them maintain shape and resist compressive forces.
Example sentence: Intermediate filaments contribute to the resilience of cells against mechanical stress and deformation.
