Cell Membrane | Cell: The unit of life | Grade 11 | Biology | Khan Academy

How does a thin layer of molecules control everything that enters and exits a cell? Welcome to the incredible world of the plasma membrane—a dynamic, semi-permeable structure that’s more than just a boundary! In this video, we explore the journey of how scientists uncovered the membrane's structure, from early chemical studies to the game-changing fluid mosaic model. You’ll learn about phospholipid bilayers, the roles of proteins and cholesterol, and how membranes stay fluid and functional. We’ll also uncover how cells move substances in and out through diffusion, osmosis, and active transport. Get ready to dive into one of the most important parts of the cell, where structure meets strategy! 00:00 - Introduction 00:22 - Phospholipids in membrane 00:51 - Cell membrane is a bilayer 01:38 - Triple layer cell membrane 02:38 - Fluid mosaic model 04:02 - Detailed membrane structure 04:30 - Proteins in the membrane + cholesterol 06:38 - Carbohydrates in the membrane 07:32 - Membrane fluidity 08:04 - Use of membrane fluidity 08:30 - Factors affecting fluidity 08:46 - Lipid composition 10:21 - Temperature 11:18 - Membrane transport 14:18 - Types of facilitated diffusion Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by Vandhana Ashok