Amphipathic compounds contain both hydrophobic and hydrophilic regions. Hydrophobic portion typically consists of large hydrocarbon chains. Hydrophilic portion can be charged or uncharged polar functional groups
Plasma membrane surrounds all cells, separating internal components from external environment. Composed of phospholipid bilayer, proteins, carbohydrates, and other components. Contains about 50% proteins, 40% lipids, and 10% carbohydrates in human cells
Pinocytosis brings small extracellular fluid molecules into cells through membrane invagination. Vesicles fuse with early endosomes to break down particles. Process primarily occurs for fat droplet absorption in humans. Requires significant cellular energy in form of ATP
Membrane proteins are common and important, comprising about 30% of human proteins. Integral proteins are permanent membrane components, while peripheral proteins are temporary. Integral proteins can be transmembrane or monotopic, while peripheral proteins are non-covalent. Proteins can be modified with fatty acids, diacylglycerol, prenyl chains, or GPI
Active transport moves molecules against concentration gradient using cellular energy. Primary active transport uses ATP, secondary uses electrochemical gradient. Essential for nutrient uptake, hormone secretion and nerve impulse transmission
Phospholipids are amphiphilic molecules found in cellular membranes. They consist of glycerol backbone with fatty acids and phosphoric acid. Phospholipids are esters of glycerol with hydrophilic headgroups