Cell Membrane: Structure and Function Cell Membrane- boundary - selectively permeable- lets certain things in - lets certain things out - maintains homeostasis - recognizes foreign cells - aids in cell recognition, communication - Fluid Mosaic Model- not rigid - many parts are constantly moving - made of organic molecules Phospholipid bilayer- two layer sandwich - phosphate group- polar “head” - hydrophilic- attracted to water - 2 fatty acids- - non-polar “tail” - hydrophobic- repels water - repels polar molecules (K+, Na+) Cholesterol - Stabilizes phospholipid tails - in hot and cold environments - important for homeostasis Proteins-move between phospholipids - peripheral- on membrane surface - integral- go through membrane - 4 types 1. Marker protein/glycoprotein - carbohydrates attached on cell exterior (extracellular) - helps in cell recognition - integral - ex: like a sign with the name of the cell Hi! I’m a blood cell (skin cell, eye cell) - important in immune system - organ transplants 2. Receptor protein - recognizes and binds to substances on extracellular side - integral - ex: like a receptionist knows what the cell wants & gets it 3. Transport/channel protein - helps substances move into & out of cell - integral - ex: like a door in the cell 4. Enzyme - help in chemical reactions - peripheral extracellular or intracellular Organelles made of membranes • • • • • • • • • • Cell membrane/plasma membrane Mitochondria Rough ER/smooth ER Golgi Lysosomes Nuclear membrane Vesicle Vacuoles Chloroplasts Cilia/flagella Organelles with NO membrane - ribosomes - Microtubule/microfilament - Cell wall - Cytoplasm - Centriole - Chromatin - Nucleolus http://www.youtube.com/watch?v=S7CJ7xZOjm0
© Copyright 2024 Paperzz