Cell Organization and Movement, Part 2: Microtubules and Intermediate Filaments

These flashcards cover key vocabulary terms and definitions related to microtubules, intermediate filaments, and their roles in cell organization and movement.

Microtubules

Hollow, cylindrical structures composed of tubulin that play key roles in providing structural support and transport in the cell.

Intermediate filaments

Nonpolar fibrous structures that provide structural support and stability to cells, composed of various proteins.

Dynamic instability

The rapid switch between growth and shrinkage in microtubules, influenced by GTP cap status.

Kinesins

Microtubule-based motor proteins that transport organelles towards the plus end of microtubules.

Dyneins

Motor proteins that transport cargo towards the minus end of microtubules, typically associated with retrograde transport.

Cilia

Hair-like structures that extend from the cell surface, involved in movement and sensory functions, composed of microtubules.

Flagella

Longer, whip-like structures that propel cells using a bending motion, also composed of microtubules.

Microtubule Organizing Centers (MTOCs)

Structures that initiate the assembly of microtubules, such as centrosomes.

Centrosome

A MTOC containing a pair of centrioles, key for microtubule organization in animal cells.

γ-Tubulin

A protein crucial for microtubule nucleation, found in the γ-tubulin ring complex.

Protofilament

The building block of microtubules, composed of linear arrangements of tubulin dimers.

MAPs (Microtubule-Associated Proteins)

Proteins that bind to microtubules to stabilize them and regulate their dynamics.

α-Tubulin and β-Tubulin

The two subunits that form tubulin dimers, essential for microtubule assembly.

GTP cap

A stable structure at the plus end of a growing microtubule that promotes polymerization.

Catastrophe

A rapid disassembly phase of microtubules when the GTP cap is lost.

Rescue

The process of transitioning from disassembly back to assembly in microtubule dynamics.

Axoneme

The core structure of cilia and flagella, consisting of microtubules arranged in a 9+2 pattern.

Intraflagellar transport (IFT)

A mechanism that transports molecular materials along the axoneme of cilia and flagella.

Non-muscle motility

Cell movement mechanisms that do not involve muscle tissue, often driven by actin and microtubule dynamics.

Cdc42

A G-protein that coordinates actin and microtubule dynamics during cell migration.

Myosins

Motor proteins that interact with actin filaments to generate force for muscle contraction and cell motility.

Post-translational modifications

Chemical modifications that occur on tubulin and affect its function and stability.

Nexins

Proteins that interconnect doublets of microtubules in cilia and flagella to maintain structural integrity.

LAMINS

Intermediate filament proteins that provide structural support to the nucleus.

Desmosomes

Adhesion structures in epithelial cells that connect intermediate filaments to cell membranes.

Filopodia

Thin, actin-rich protrusions that help guide growth cones during neuronal development.

Pericentriolar material (PCM)

The material surrounding centrioles in a centrosome, critical for microtubule nucleation.

Triplet microtubules

Groups of three microtubules found in centrioles that provide structural stability.

Neuronal growth cones

Dynamic structures at the tip of growing axons, guiding their development through sensory signaling.

ATPase activity

An activity that hydrolyzes ATP to provide energy for molecular motors like kinesin and dynein.

Sliding mechanism

The process by which dyneins induce bending in cilia and flagella by sliding adjacent microtubules.

Phosphorylation

A regulatory modification that can control the assembly and disassembly of intermediate filaments.