Cytoskeleton Overview and Functions

<p>Through ATP hydrolysis (D)</p> Signup and view all the answers

<p>Polymerization and crosslinking of actin filaments (B)</p> Signup and view all the answers

<p>They move cargo towards the (+) end of microtubules. (B)</p> Signup and view all the answers

<p>Flagella have a wavelike pattern of beating. (D)</p> Signup and view all the answers

<p>It binds tubulin and inhibits microtubule polymerization. (D)</p> Signup and view all the answers

<p>New microtubules grow outward from the centrosome. (C)</p> Signup and view all the answers

<p>To transport cargo towards the (−) end of microtubules. (A)</p> Signup and view all the answers

<p>It serves as the primary microtubule-organizing center in the cell. (B)</p> Signup and view all the answers

<p>The rapid turnover of microtubule components. (C)</p> Signup and view all the answers

<p>They move mucus and dust away from the alveoli. (A)</p> Signup and view all the answers

<p>It is necessary for the assembly of tubulin dimers into microtubules. (B)</p> Signup and view all the answers

<p>Support cell shape and provide mechanical stability (C)</p> Signup and view all the answers

<p>They are made up of a variety of protein subunits that differ by cell type. (C)</p> Signup and view all the answers

<p>By undergoing polymerization and depolymerization for shape change (A)</p> Signup and view all the answers

<p>Microfilaments have a diameter of approximately 7 nm. (C)</p> Signup and view all the answers

<p>They link protein filaments to organelles and the plasma membrane. (B)</p> Signup and view all the answers

<p>Cilia (D)</p> Signup and view all the answers

<p>To allow for rapid cellular responses to environmental changes (A)</p> Signup and view all the answers

<p>By providing tracks along which motor proteins can transport organelles (D)</p> Signup and view all the answers

<p>Enabling cell crawling and contraction (C)</p> Signup and view all the answers

<p>Their ability to rapidly add or lose tubulin dimers (A)</p> Signup and view all the answers

<p>Coiled-coil dimers associating in an antiparallel fashion (B)</p> Signup and view all the answers

<p>They provide mechanical support to the nuclear envelope. (C)</p> Signup and view all the answers

<p>By modification through phosphorylation (B)</p> Signup and view all the answers

<p>Thicker than actin filaments and thinner than microtubules (C)</p> Signup and view all the answers

<p>Disassembly of the nuclear lamina (D)</p> Signup and view all the answers

<p>Enable cellular movement and shape change (A)</p> Signup and view all the answers

<p>More than 50 different proteins classified into six groups exist. (D)</p> Signup and view all the answers

<p>To provide mechanical strength and structure (C)</p> Signup and view all the answers

<p>They have tight binding sites facilitating head-to-tail interactions. (B)</p> Signup and view all the answers

<p>It influences the speed of elongation at each filament end. (D)</p> Signup and view all the answers

<p>Networks (A)</p> Signup and view all the answers

<p>They increase the surface area for nutrient transport. (D)</p> Signup and view all the answers

<p>Loosely spaced actin filaments capable of contraction. (D)</p> Signup and view all the answers

<p>They exhibit treadmilling, maintaining a constant length. (D)</p> Signup and view all the answers

<p>It elongates significantly faster. (B)</p> Signup and view all the answers

<p>Through its three-dimensional network of actin filaments. (D)</p> Signup and view all the answers

<p>The dissociation of actin subunits. (A)</p> Signup and view all the answers

Filamin forms cross-links between orthogonal actin filaments, creating a loose 3D network. This network contributes to the overall structure and organization of the cell.

Myosin is a motor protein that converts chemical energy from ATP into mechanical energy, generating force and movement. This is essential for muscle contraction and cell movement.

Cell crawling is a fundamental form of cell locomotion that involves a coordinated cycle of extending protrusions, attaching to the substrate, and retracting the trailing edge.

Protrusion in cell crawling is driven by the polymerization and crosslinking of actin filaments at the leading edge of the cell, creating extensions like pseudopodia or lamellipodia.

Attachment during cell crawling involves specialized structures called focal adhesions, which connect the cell's cytoskeleton to the extracellular matrix of the substrate.

A network of protein filaments within the cytoplasm of most cells, extending from the nuclear membrane to the plasma membrane. It provides mechanical support, helps stabilize organelles, and aids in cell-to-cell attachments.

One type of cytoskeletal fiber, intermediate filaments are thicker than actin filaments but thinner than microtubules. They are found in regions of the cell subject to mechanical stress, helping to stabilize organelles and connect cells.

Intermediate filaments are formed by the assembly of protein dimers into tetramers, then these tetramers associate to form a rope-like structure of eight protofilaments. This arrangement gives them strength and stability.

Unlike microtubules and actin filaments, intermediate filaments are not dynamic structures; they don't readily assemble or disassemble. Their assembly and disassembly are often regulated by phosphorylation.

The nuclear lamina is a specialized layer of intermediate filaments that lines the inner surface of the nuclear membrane. It's composed of lamin proteins and provides structural support for the nucleus.

The nuclear lamina is disassembled during mitosis by phosphorylation of lamin proteins. This allows the nuclear membrane to break down, enabling access to the chromosomes for replication.

More than 50 different intermediate filament proteins exist, classified into six groups based on their amino acid sequences. Each group is associated with specific cell types and functions.

Actin filaments are the most abundant cytoskeletal proteins in most cells. They are particularly concentrated beneath the plasma membrane, where they form a network that supports the cell structure and enables movement.

Globular proteins that assemble into long filaments, forming the cytoskeleton's building blocks.

Long, thread-like structures made of actin monomers, serving as the structural foundation of the cytoskeleton.

A property of actin filaments where one end grows faster than the other, allowing them to extend and shorten dynamically.

A process where actin monomers add to the plus end of a filament while monomers detach from the minus end, creating a constant flow of assembly and disassembly.

Proteins that interact with actin filaments, influencing their organization and function.

A tightly packed arrangement of actin filaments, providing structural support for cell projections like microvilli.

A loosely interconnected network of actin filaments, providing a gel-like structure that determines cell shape and movement.

Finger-like projections from the cell surface supported by bundles of actin filaments, increasing surface area for nutrient absorption.

A ring of actin filaments that forms during cell division, pinching the cell membrane and creating two daughter cells.

A mesh-like layer of actin filaments and associated proteins beneath the cell membrane, regulating cell shape and surface activities.

The major microtubule-organizing center in cells, responsible for initiating microtubule growth and organizing microtubule arrangements.

A process where microtubules can grow and shrink dynamically, with tubulin dimers assembling and disassembling at their ends.

A type of cytoskeletal filament that plays critical roles in cell structure, transport, and movement.

A drug that binds to tubulin and prevents microtubule polymerization, disrupting cell division.

A drug that stabilizes microtubules, preventing their disassembly, which can disrupt cell division.

Motor proteins that move cargo along microtubules towards the (+) end, also known as anterograde transport.

Motor proteins that move cargo along microtubules towards the (-) end, also known as retrograde transport.

Short, hair-like structures that extend from the surface of some cells, responsible for movement of fluids or the cell itself.

Long, whip-like structures that extend from the surface of some cells, responsible for movement.

A movement that creates a back-and-forth motion, used by cilia and flagella.

A network of protein filaments that extend throughout the cytoplasm of eukaryotic cells, providing structural support, organizing the cytoplasm, and enabling cell movements.

The cytoskeleton plays a crucial role in shaping the cell, organizing its internal components, and facilitating various cellular processes.

The cytoskeleton comprises a dynamic network of protein filaments, constantly reorganizing as cells change shape.

The cytoskeleton is composed of three main types of protein filaments: actin filaments, intermediate filaments, and microtubules, arranged in increasing diameter.

Microtubules are long, hollow cylinders formed by the assembly of tubulin dimers.

Microtubules play key roles in determining cell shape, transporting organelles, separating chromosomes during division, and powering cilia and flagella.

Microtubules have distinct ends, a fast-growing plus end and a slow-growing minus end, creating a directionality essential for their functions.

Actin filaments are thin, flexible filaments composed of the protein actin, forming dynamic networks.

Actin filaments are involved in cell shape, muscle contraction, cell crawling, and forming microvilli in the intestines.

Intermediate filaments are strong, rope-like structures composed of various proteins, providing structural support to cells.