cell membrane

The double bonds in unsaturated fatty acids create "kinks" that prevent tight packing, maintaining fluidity at low temperatures.

Cholesterol acts as a temperature buffer, preventing excessive fluidity at high temperatures and excessive rigidity at low temperatures.

The Fluid Mosaic Model dictates that proteins can move laterally within the plane of the lipid bilayer.

Active transport moves solutes against their concentration gradient, which is an endergonic process requiring ATP.

Glycoproteins are proteins covalently bonded to carbohydrate chains, playing key roles in cell-cell recognition.

Robertson used electron microscopy to observe the "railroad track" appearance of membranes, implying three distinct layers.

The hydrophilic phosphate head and hydrophobic fatty acid tails make the molecule amphipathic.

Facilitated diffusion uses transmembrane proteins to move molecules that cannot pass through the lipid bilayer directly.

Peripheral proteins are loosely attached to the surface, usually via non-covalent interactions like ionic or hydrogen bonds.

Shorter chains decrease van der Waals interactions, and double bonds create fluidity; this combination results in the highest fluidity.

Glycolipids act as markers for cell identification and adhesion in the extracellular matrix.

Freeze-fracture techniques show proteins distributed within the bilayer, confirming the mosaic nature.

According to Fick's law, the rate of diffusion is directly proportional to the steepness of the concentration gradient.