https://www.khanacademy.org/science/biology/membranes-and-transport/diffusion-and-osmosis/v/diffusion-video 2023-09-14T11:22:40.102153098Z Diffusion - Introduction Diffusion occurs when particles move from an area of high concentration to low concentration, creating a concentration gradient. This natural, energy-free process occurs due to the random movement of particles, with a higher chance of particles moving from the high concentration side. Over time, this leads to an equilibrium state with equal concentrations on both sides. Sal Khan video https://cdn.kastatic.org/googleusercontent/RUQQq8sEkvIHMaAACUfO9mwKcYl24deX2nahzhdiPcW8Hu02regQ_phJzKBOoUg3VABgzF1J8ziAQfdkVITX558 Diffusion - Introduction Diffusion occurs when particles move from an area of high concentration to low concentration, creating a concentration gradient. This natural, energy-free process occurs due to the random movement of particles, with a higher chance of particles moving from the high concentration side. Over time, this leads to an equilibrium state with equal concentrations on both sides. https://cdn.kastatic.org/ka-youtube-converted/a_Y9wBQ610o.mp4/a_Y9wBQ610o.mp4 367 Cell and Cell Organelles 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 and Cell Organelles https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/v/hypotonic-isotonic-and-hypertonic-solutions-tonicity 2023-09-14T11:22:40.102153098Z Hypotonic, isotonic, and hypertonic solutions (tonicity) Cells react differently in hypotonic, isotonic, and hypertonic solutions. In a hypotonic solution, water rushes into the cell causing it to expand or even burst. In an isotonic solution, there is no net flow of water, keeping the cell stable. In a hypertonic solution, water leaves the cell, causing it to shrivel. These reactions are due to the semipermeable nature of cell membranes and the concentration of solutes. Sal Khan video https://cdn.kastatic.org/googleusercontent/5T4Kl6aMA2bQE3_l4YOlLy_yyW_z5jFkn8pkFNylrj0XdYYE8qift3NyRvstZ1_Tp-p28YkBaMcTehT0LO17SHNB Hypotonic, isotonic, and hypertonic solutions (tonicity) Cells react differently in hypotonic, isotonic, and hypertonic solutions. In a hypotonic solution, water rushes into the cell causing it to expand or even burst. In an isotonic solution, there is no net flow of water, keeping the cell stable. In a hypertonic solution, water leaves the cell, causing it to shrivel. These reactions are due to the semipermeable nature of cell membranes and the concentration of solutes. https://cdn.kastatic.org/ka-youtube-converted/afWnU10ZNfg.mp4/afWnU10ZNfg.mp4 390 Cell and Cell Organelles https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:cell-and-cell-organelles/x0f256b8de9c7cf34:diffusion-and-osmosis/e/diffusion-and-osmosis 2022-08-23T00:49:21.470582385Z Diffusion, osmosis, and tonicity Test your knowledge on the processes of diffusion, osmosis, and tonicity! Ashley exercise https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/membrane-permeability/v/plant-cell-walls 2022-11-16T04:22:43.7414897Z Plant cell walls The cell wall surrounds the plant cell, providing both structure and protection. Plant cell walls are made up mostly of cellulose, and also include hemicellulose and pectin. Plant cells connect directly to one another via tunnels in their cell walls called plasmodesmata. video https://cdn.kastatic.org/googleusercontent/f1qMxaZZgQlEIw_d6Y37Y2BWCKKcj5_x5ck6SHI1VgGVR8OkAd76PhcPj3EMDrUKh_gWIdaTOh9Ro8-mGCYsVdHC Plant cell walls The cell wall surrounds the plant cell, providing both structure and protection. Plant cell walls are made up mostly of cellulose, and also include hemicellulose and pectin. Plant cells connect directly to one another via tunnels in their cell walls called plasmodesmata. https://cdn.kastatic.org/ka-youtube-converted/zdvKhaQxvag.mp4/zdvKhaQxvag.mp4 463 Cell and Cell Organelles https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:cell-and-cell-organelles/x0f256b8de9c7cf34:cell-organelles/e/prokaryotic-and-eukaryotic-cells-1 2026-04-08T08:09:55.69362548Z Prokaryotic and eukaryotic cells Check your understanding of the differences between prokaryotic and eukaryotic cells. Moumita Sen exercise https://www.khanacademy.org/science/bridge-course-class-11th-biology/xfa1bbeaa3bc88e64:cells-and-tissues/xfa1bbeaa3bc88e64:cells/v/mitochondria-plastids 2024-01-16T04:11:35.384208864Z Mitochondria & plastids Let's summarise mitochondria and plastids. Mahesh Shenoy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Mitochondria & plastids Let's summarise mitochondria and plastids. https://cdn.kastatic.org/ka-youtube-converted/r6J5v0aEkFA.mp4/r6J5v0aEkFA.mp4 187 Cell and Cell Organelles https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:cell-and-cell-organelles/x0f256b8de9c7cf34:cell-organelles/v/endoplasmic-reticulum-and-golgi 2023-01-12T07:30:45.138114799Z Endoplasmic reticulum and Golgi bodies Let's understand the endomembrane system. Khadijatul Qubra video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Endoplasmic reticulum and Golgi bodies Let's understand the endomembrane system. https://cdn.kastatic.org/ka-youtube-converted/NcqXQFQBEJU.mp4/NcqXQFQBEJU.mp4 960 Cell and Cell Organelles https://www.khanacademy.org/science/mh-grade-8-science/x0f256b8de9c7cf34:cell-and-cell-organelles/x0f256b8de9c7cf34:cell-organelles/v/lysosomes-and-vacuoles 2023-01-12T07:30:45.138114799Z Lysosomes and vacuoles Let's understand the role of these tiny compartments inside our cells - Lysosomes and vacuoles. Khadijatul Qubra video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Lysosomes and vacuoles Let's understand the role of these tiny compartments inside our cells - Lysosomes and vacuoles. https://cdn.kastatic.org/ka-youtube-converted/9bMqL-9Tiow.mp4/9bMqL-9Tiow.mp4 692 Cell and Cell Organelles https://www.khanacademy.org/science/revision-term-1-ka-science-grade-9/x07cce91f26fedd3c:week-2/x07cce91f26fedd3c:introduction-to-cells/e/parts-of-the-cell-and-their-functions 2026-04-08T01:15:04.085520103Z Parts of the cell and their functions Let's revise the different parts of the cell, like the nucleus, Golgi apparatus, etc., and the roles they play in the cell. Moumita Sen exercise