Cell Biology: Endocytosis, Cytoskeleton, Adhesion, and Cell Junctions

A set of vocabulary flashcards covering endocytosis, cytoskeletal motor proteins, cell adhesion, junctions, membrane properties, and related cellular components.

Exocytosis

The cellular transport process where a transport vesicle moves to and fuses with the plasma membrane to release material outside of the cell.

Endocytosis

The cellular process of internalizing macromolecules inside membrane-bound vesicles through membrane pocketing, deepening, vesicle formation, and pinching off.

Receptor-Mediated Endocytosis

A selective uptake pathway triggered by specific solutes binding to cell-surface receptors, which cluster into coated pits to form internalized coated vesicles.

Coated Pit

A specialized cell-membrane region containing specific coat proteins where solute-bound receptors cluster before forming a coated vesicle.

Low-Density Lipoprotein (LDL)

A molecule that binds specific receptors on the cell surface to be selectively internalized via receptor-mediated endocytosis.

Motor Protein

A protein that utilizes energy from ATP hydrolysis to transport cargo along cytoskeletal structures.

Kinesin

A motor protein that moves cargo along microtubules toward the plus end, such as vesicles moving from the Golgi toward the plasma membrane.

Dynein

A motor protein that moves along microtubules toward the minus end and powers microtubule sliding that causes ciliary and flagellar bending.

Myosin

A motor protein that moves along microfilaments (actin) toward the plus end to power muscle-cell shortening.

Microtubules

Cytoskeletal fibers originating from the central microtubule-organizing center that act as tracks for motor proteins like kinesin and dynein.

Microfilaments

Cytoskeletal structures composed of actin that undergo rapid growth at the advancing edge of a cell to drive protrusion and cell movement.

Basal Lamina

The bottom layer of the extracellular matrix associated with epithelial sheets that provides a surface for cell attachment.

Cadherin

A transmembrane cell-cell adhesion protein that binds to cadherin proteins on neighboring cells to connect cells in tissue sheets.

Integrin

A cell-surface receptor protein that anchors cells to the extracellular matrix (ECM) and connects external attachments to the internal cytoskeleton.

Tight Junction

A cell junction that seals neighboring epithelial cells together to create a permeability barrier against solute movement.

Adherens Junction

A cadherin-mediated cell-cell junction that connects cells into organized tissue sheets.

Desmosome

A cell junction connected to intermediate filaments that provides mechanically strong attachments between cells to withstand stress.

Gap Junction

A cell junction that creates passages between adjacent cells allowing small molecules to move directly between them.

Epidermolysis Bullosa Simplex

A genetic condition caused by mutations in keratin genes, leading to defective intermediate filament support, fragile skin, and blistering under mechanical stress.

Keratins

Intermediate filament proteins in skin cells that provide mechanical strength and resist structural strain.

Signal Recognition Particle (SRP)

A cytosolic protein complex that binds the ER signal sequence on a nascent protein and directs it to the SRP receptor on the ER membrane.

Homeoviscous Adaptation

An adaptive response where cells alter membrane lipid composition, such as incorporating polyunsaturated chains, to preserve appropriate membrane fluidity at cold temperatures.

Endosymbiotic Theory

The theory stating that mitochondria and chloroplasts originated from ancestral bacterial and cyanobacterial cells, supported by multiple shared structural and functional traits.