110 likes | 136 Views
Dive into the intricacies of the eukaryotic cell membrane, its selective permeability, phospholipid bilayer structure, and the vital role of proteins and cholesterol in maintaining cell integrity and assisting in transport. Understand how the membrane allows specific molecules to enter and leave, supporting homeostasis and cellular function.
E N D
Cell Membrane • Cell membrane: the flexible boundary of a cell (also called a plasma membrane) • It separates a cell from its surroundings. • It allows nutrients to enter and waste to be removed.
Cell Membrane • Homeostasis: maintaining a healthy balance • The cell membrane allows some molecules into the cell and keeps others out.
Cell Membrane • Selective permeability: allowing only certain molecules to enter and leave the cell • Selective permeability is like a screen on a window
Cell Membrane • What gets in? • H2O freely enters cell • O2 in ,CO2 out • Na and Ca at certain times in certain amounts • Waste leaves but can’t reenter
Membrane Structure • Phospholipid: lipid with a glycerol backbone and two fatty acid chains, and a phosphate group
Membrane Structure • The polar head is hydrophilic: it likes water • Fatty acid tail is hydrophobic: it does not like water. • They form a bilayer
Membrane Structure • The cell membrane also contains proteins to help support the cell structure. • Cholesterol to keep the fatty acid tails from sticking together
Membrane Structure • Fluid Mosaic Model: the organization of the cell membrane. • Fluid because it is not fixed in a particular spot • Mosaic because of the patterns the proteins make
Membrane Structure • Proteins in the membrane function as: • Transport proteins: moving molecules across the membrane • Identify chemicalsignals