IndietroCell Membrane Structure and Transport Mechanisms
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Termini in questo insieme (20)
Saturated fatty acid tails make membranes less permeable due to tight packing, while unsaturated tails increase permeability by creating kinks that prevent tight packing.
The cytoskeleton provides structural support, enables cell movement, facilitates intracellular transport, and organizes cell division.
Membrane specializations include cilia for movement or fluid flow, microvilli for increased surface area, and folds for enhanced absorption.
The three types are tight junctions (seal cells), desmosomes (anchor cells), and gap junctions (allow communication).
Passive transport moves substances down their concentration gradient without energy input.
Active transport moves substances against their concentration gradient using cellular energy, usually ATP.
Diffusion is the movement of molecules from an area of higher concentration to lower concentration until equilibrium is reached.
Includes simple diffusion, facilitated diffusion via carrier proteins, and osmosis for water movement.
Includes primary active transport using ATP pumps and secondary active transport using ion gradients.
Tight junctions create a seal between adjacent cells to prevent leakage of molecules.
Desmosomes provide mechanical strength by anchoring cells together.
Gap junctions allow direct communication between cells via channels for ions and small molecules.
Cilia move fluid or particles across the cell surface through coordinated beating.
Microvilli increase surface area to enhance absorption and secretion.
Simple diffusion passes directly through the membrane; facilitated diffusion requires carrier or channel proteins.
Osmosis is driven by differences in solute concentration across a semipermeable membrane, causing water to move.
The Na+/K+ pump uses ATP to move sodium out and potassium into the cell against their gradients.
Uses energy from an ion gradient created by primary active transport to move other substances against their gradient.
Increased fluidity from unsaturated tails allows more molecule movement across the membrane.
Active transport maintains ion gradients and cellular homeostasis necessary for cell function.