Membrane Permeability - AP Biology

Stabilize cell structure by linking to cytoskeleton. Connect membrane to internal cellular framework for structural support.

Release of substances from a cell via vesicles. Vesicles fuse with membrane to release contents outside cell.

Cells may swell and burst. Water enters cells causing them to expand beyond capacity.

Facilitated diffusion involves transport proteins. Simple diffusion occurs directly through lipids without proteins.

Phospholipids. Phospholipids arrange with hydrophobic tails inward, hydrophilic heads outward.

Facilitate water transport across membranes. Channel proteins specifically designed for rapid water movement.

Cell recognition and signaling. Carbohydrate-protein complexes function as cellular identification tags.

Maintain fluidity and stability of the membrane. Cholesterol modulates fluidity - reduces at high temps, increases at low temps.

Active transport. Moving substances against their concentration gradient requires energy input.

Proteins and lipids. These molecules form signaling pathways for cellular communication.

Large or polar molecules. Size or polarity prevents direct passage through the lipid bilayer.

Higher temperatures increase movement. Kinetic energy increases with temperature, enhancing molecular motion.

No change in cell volume. Equal solute concentrations inside and outside maintain equilibrium.

Osmosis. Water moves down its concentration gradient across semipermeable membranes.

From high to low concentration. Passive transport follows concentration gradients without energy.

Transport, signaling, attachment, and enzymatic activity. Membrane proteins perform diverse roles essential for cell function.

Sodium-potassium pump. Uses ATP to maintain electrochemical gradients across membranes.

Receive and transmit signals. Detect and respond to chemical signals from environment.

Decrease fluidity at high temperatures. Cholesterol prevents excessive fluidity by restricting lipid movement.

Diffusion. Movement down concentration gradients without energy input.

Increase fluidity. Double bonds create kinks that prevent tight packing of lipids.

Endocytosis and exocytosis. Membrane-bound vesicles transport large or bulk materials.

Higher temperatures increase permeability. Heat increases molecular motion, making membranes more permeable.

Describes the membrane as a fluid structure with proteins embedded. Explains membrane structure as dynamic with mobile protein components.

Cell recognition and communication. Sugar chains on proteins and lipids serve as identification markers.

Concentration gradient. Difference in concentration provides the energy for molecular movement.

Phospholipids, proteins, cholesterol, and carbohydrates. These four components work together to form the membrane structure.

Bind and transport specific molecules across membranes. Change shape to move specific molecules across the membrane.

Cells may shrink and crenate. Water leaves cells causing them to lose volume and wrinkle.