Cytoskeleton Overview

Flashcards covering key concepts about cytoskeleton components and their functions in cellular structure and movement.

Cytoskeleton

An interconnected network of protein fibers that extends throughout the cytoplasm, providing structural support and facilitating cellular movements.

Motor Proteins

Hydrolyzes ATP to generate mechanical force

Two types are Kinesin and Dynein

Microtubules

Hollow tubes composed of α-tubulin and β-tubulin dimers, involved in intracellular transport and cell motility.

Typically 13 protofilaments form a cylinder 25 nm (nanometers) in diameter

Actin Filaments

Solid rods made of actin globular subunits that form a twisted double helix, crucial for cell motility and muscle contraction. Its the thinnest cytoskeleton filament

7nm (nanometers) in diameter

Cell motility (Functions of Actin Filaments)

Forms a 3-D network beneath the plasma membrane that pushes the membrane forward

Intermediate Filaments

Relatively stable rope-like fibres composed of various proteins that provide mechanical resilience and maintain cell shape.

They participate in nuclear positioning, signal transduction, and cell-cell adhesion

8 - 12 nm (nanometers) in diameter

Intermediate Filaments Production Flow

Monomers → Dimers → Tetramers → Unit-length Filaments → Mature IF’s

Microtubule-Organizing Centre (MTOC)

A structure, often the centrosome, that nucleates the formation of microtubules.

Kinesin

A motor protein that moves cargo toward the plus end of microtubules.

Dynein

A motor protein that transports cargo toward the minus end of microtubules.

Axoneme

The structural core of cilia and flagella, characterized by a 9+2 arrangement of microtubules.

Cilia and Flagella

Cellular structures that enable motility and movement of extracellular fluids.

Motility (Functions of Cilia and Flagella)

The ability of a cell or organism to move on its own

Doesn’t depend on external sources to move it

Microvilli (Functions of Actin Filaments)

Surface projections of epithelial cells supported by actin filaments, increasing absorptive area.

Muscle Contraction (Function of Actin Filaments)

Parallel actin filaments interact with myosin to slide past one another

Intracellular Transport (Function of Microtubules)

Acts as tracks for motor proteins moving vesicles and organelles

Mitosis (Function of Microtubules)

Forms the spindle apparatus that separates chromosomes

Cilia and Flagella (Functions of Microtubules)

Constitute the core “9+2” axoneme that powers cell-surface protrusions