Flashcards: Cell Membrane Transport Mechanisms — 23 cartões

Lipid bilayer permeability — limit?

Restricts passage of polar molecules and ions.

Passive transport types — examples?

Simple diffusion, facilitated diffusion, osmosis.

Simple diffusion — mechanism?

Small molecules pass directly through lipid bilayer.

Facilitated diffusion — role?

Uses proteins to transport molecules along gradient.

Membrane proteins — in diffusion?

Carrier and channel proteins facilitate transport.

Aquaporins — function?

Allow passive water movement across membrane.

Active transport — process?

Moves substances against their gradient using energy.

ATP-driven transport — example?

Na⁺-K⁺ pump uses ATP hydrolysis.

Na⁺-K⁺ pump — function?

Maintains Na⁺ and K⁺ ionic gradients.

Secondary active transport — mechanism?

Couples movement of two molecules, one down gradient.

Endocytosis, exocytosis — process?

Vesicle-mediated transport in and out of cell.

Cytotic transport — characteristic?

Involves membrane deformation, vesicle formation.

Simple diffusion — molecules?

Lipid-soluble small molecules like O₂, CO₂.

Facilitated diffusion — proteins?

Carrier and channel proteins.

Membrane proteins — types?

Carrier proteins and ion channels.

Water movement — channels?

Aquaporins.

Active transport — energy source?

ATP hydrolysis or other forms.

Na⁺-K⁺ pump — energy?

Uses ATP to exchange ions.

Secondary active transport — example?

Na⁺-glucose cotransporter.

Endocytosis — involves?

Membrane invagination and vesicle formation.

Exocytosis — involves?

Vesicle fusion with membrane to release contents.

Cytotic transport — characteristic?

Energy-dependent, vesicle-based, membrane deformation.

Lipid bilayer — permeability?

Allows small, hydrophobic molecules, restricts ions.