https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/v/diffusion-and-osmosis 2023-04-04T21:01:09.417661961Z Diffusion and osmosis Diffusion refers to the movement of molecules from an area of high concentration to an area of lower concentration. Osmosis is a type of diffusion specifically for water molecules moving across a semi-permeable membrane. A concentration gradient is the difference in concentration of a substance between two areas, which drives diffusion or osmosis. Sal Khan video https://cdn.kastatic.org/googleusercontent/GAWZF4VBIdWVcjS-7wl2dscf4EwnEGvB8xTW_3plAmQZ7LtwQNjzEboBjQg3vYG4lDy6uKYj07N3Qq7-OcQQCTxktg Diffusion and osmosis Diffusion refers to the movement of molecules from an area of high concentration to an area of lower concentration. Osmosis is a type of diffusion specifically for water molecules moving across a semi-permeable membrane. A concentration gradient is the difference in concentration of a substance between two areas, which drives diffusion or osmosis. https://cdn.kastatic.org/ka-youtube-converted/aubZU0iWtgI.mp4/aubZU0iWtgI.mp4 1139 Cell transport mechanisms https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/v/osmosis 2024-05-06T19:22:43.24334365Z Osmosis Osmosis is a process where water molecules move from an area of low solute concentration to high solute concentration through a semipermeable membrane. This movement can be influenced by factors like solute size and charge. Understanding osmosis helps us grasp how cells maintain balance and control their internal environment. Sal Khan video https://cdn.kastatic.org/googleusercontent/5zu_ewQLVv3K9YYdURQ6En-3UA3eyDo-0dRBO5hg88GHbmgIfSeBEKAUNuEPQOBPiPQxNK0Y36qXLMUFn9hiRNSl Osmosis Osmosis is a process where water molecules move from an area of low solute concentration to high solute concentration through a semipermeable membrane. This movement can be influenced by factors like solute size and charge. Understanding osmosis helps us grasp how cells maintain balance and control their internal environment. https://cdn.kastatic.org/ka-youtube-converted/rCNlG_j_gSM.mp4/rCNlG_j_gSM.mp4 484 Cell transport mechanisms https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/facilitated-diffusion/v/facilitated-diffusion 2023-04-04T21:01:09.417661961Z Facilitated diffusion Facilitated diffusion is a type of passive transport that uses specialized proteins, such as channel proteins and carrier proteins, to help molecules move across a cell membrane. In this process, molecules can move down their concentration gradient without requiring any energy input from the cell. video https://cdn.kastatic.org/googleusercontent/j3iz6FxjluOP1LA1JOB3dwfz7toKRngFRsx4MunfxU-UA7746u8LxYDbVz3PXE9-cSl-r8QtLmDFPWbBUkea_rc Facilitated diffusion Facilitated diffusion is a type of passive transport that uses specialized proteins, such as channel proteins and carrier proteins, to help molecules move across a cell membrane. In this process, molecules can move down their concentration gradient without requiring any energy input from the cell. https://cdn.kastatic.org/ka-youtube-converted/8HlVy__J8XA.mp4/8HlVy__J8XA.mp4 395 Cell transport mechanisms https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/a/osmosis 2024-01-19T18:25:11.349624553Z Osmosis and tonicity Osmosis and tonicity. Hypertonic, isotonic, and hypotonic solutions and their effect on cells. article https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/facilitated-diffusion/a/diffusion-and-passive-transport 2021-04-29T07:57:58Z Diffusion and passive transport Covers selective permeability of membranes, diffusion, and facilitated diffusion (including channels and carrier proteins). article https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/e/mechanisms-of-transport--tonicity-and-osmoregulation-exercise 2023-08-07T17:09:37.131449861Z Mechanisms of transport: tonicity and osmoregulation Test your knowledge of mechanisms of transport: tonicity and osmoregulation! Ashley Mucha exercise https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/facilitated-diffusion/e/facilitated-diffusion 2025-11-24T20:40:43.982882282Z Facilitated diffusion Test your knowledge of facilitated diffusion! Megan Cohn exercise https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/membrane-transport/v/endocytosis-phagocytosis-and-pinocytosis 2022-11-16T04:22:43.7414897Z Endocytosis, phagocytosis, and pinocytosis Phagocytosis is the process by which a cell engulfs and internalizes a large particle, such as a bacterium, by extending its membrane around it. Pinocytosis is similar, but instead the cell engulfs droplets of extracellular fluid, taking in any dissolved substances within. Both phagocytosis and pinocytosis are forms of endocytosis. video https://cdn.kastatic.org/googleusercontent/J8korir2x9DjX2wj95SlH6A9y_Hy794t_Q-kdp8TiZzvS570svKHMapJKtc1E3QcFaY1lNZdfWw6gU8r_nVAdOij Endocytosis, phagocytosis, and pinocytosis Phagocytosis is the process by which a cell engulfs and internalizes a large particle, such as a bacterium, by extending its membrane around it. Pinocytosis is similar, but instead the cell engulfs droplets of extracellular fluid, taking in any dissolved substances within. Both phagocytosis and pinocytosis are forms of endocytosis. https://cdn.kastatic.org/ka-youtube-converted/QspmZf_yWyU.mp4/QspmZf_yWyU.mp4 278 Cell transport mechanisms https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/membrane-transport/v/exocytosis 2022-11-16T04:22:43.7414897Z Exocytosis Exocytosis is a form of bulk transport during which large numbers of molecules are transported out of the cell. In exocytosis, a vesicle (a small, membrane-bound compartment) containing the molecules to be released fuses with the cell membrane, and the contents of the vesicle are expelled. Exocytosis is important for the transport of neurotransmitters. video https://cdn.kastatic.org/googleusercontent/_aV5PG_I6CMsjjgJE0Gjlk9Mjkbps-pMSXOV0NxjxHNkp2ukUfcJGDYmHMD6xEMAFMrfiHChopf_TSYDChxHQVxj Exocytosis Exocytosis is a form of bulk transport during which large numbers of molecules are transported out of the cell. In exocytosis, a vesicle (a small, membrane-bound compartment) containing the molecules to be released fuses with the cell membrane, and the contents of the vesicle are expelled. Exocytosis is important for the transport of neurotransmitters. https://cdn.kastatic.org/ka-youtube-converted/VOzV4d0HKis.mp4/VOzV4d0HKis.mp4 257 Cell transport mechanisms https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/membrane-transport/a/bulk-transport 2025-01-07T20:24:30.121144203Z Bulk transport Endocytosis and exocytosis. Phagocytosis, pinocytosis, and receptor-mediated endocytosis. article