What is osmosis

Introduction Imagine playing basketball with your friends on a hot summer day. By the end of the game, you feel thirsty. You decide to drink some water. But have you ever wondered how your body absorbs it? It happens because of osmosis. We will look at how osmosis happens and why it is important for our bodies. What is a semipermeable membrane? Before we jump into osmosis, we need to understand some important things about cells. The cells in our bodies are surrounded by a wall-like structure called a cell membrane. This membrane is special because only water and very small molecules can pass through it. We use the word semipermeable to describe the ability to only let certain things pass through a membrane. Water and small molecules can pass through a semipermeable membrane and into a cell (Let’s Talk Science using an image by Why is this membrane important? It’s because water must pass through semipermeable membranes to travel from one place in our body to another. What are solutes and solvents? Osmosis is when water molecules travel from a place with low solute concentration to a place with high solute concentration. To understand this better, we need to talk about solutes and solvents. A solute is a chemical that can dissolve in a solvent. Chemicals that can do this are called soluble. When you dissolve one or more solutes into a solvent, you get a solution. Sugar and salt are both chemicals that are soluble in water. When you dissolve a soluble chemical like sugar in w...

Passive Transport: Osmosis Osmosis is the diffusion of water through a semipermeable membrane according to the concentration gradient of water across the membrane. Whereas diffusion transports material across membranes and within cells, osmosis transports only water across a membrane and the membrane limits the diffusion of solutes in the water. Osmosis is a special case of diffusion. Water, like other substances, moves from an area of higher concentration to one of lower concentration. Imagine a beaker with a semipermeable membrane, separating the two sides or halves ( Figure 3). On both sides of the membrane, the water level is the same, but there are different concentrations on each side of a dissolved substance, or solute, that cannot cross the membrane. If the volume of the water is the same, but the concentrations of solute are different, then there are also different concentrations of water, the solvent, on either side of the membrane. Figure 3 In osmosis, water always moves from an area of higher concentration (of water) to one of lower concentration (of water). In this system, the solute cannot pass through the selectively permeable membrane. A principle of diffusion is that the molecules move around and will spread evenly throughout the medium if they can. However, only the material capable of getting through the membrane will diffuse through it. In this example, the solute cannot diffuse through the membrane, but the water can. Water has a concentration gradient...

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Osmosis is a group of people that take complicated medical topics and teach them in an organized and effective way so that the information seeps into your brain and leads to longer retention… oh wait, not that Osmosis? Well, then, simply put, osmosis is how water molecules move across a semipermeable membrane that separates two solutions. It can be thought of as passive diffusion of water and it requires no energy. When water molecules move like this, they end up equalizing the concentrations of the solutions on either side of the membrane. This is possible because a semipermeable membrane, like the So let’s say that we’re looking at a lab beaker that is filled with a salt water solution, and we separate it in two compartments - A and B - with a semipermeable membrane in the middle. Now, first off - the salt which is sodium chloride will separates out into sodium ions and chloride ions once it’s in the water. And since the concentration of sodium and chloride ions is the same on either side of the membrane, we say that A and B are Now, inside the two compartments, water molecules and sodium and chloride ions are moving around and bouncing off each other. It’s a bit like two big dance parties happening in two adjacent warehouses that are connected by doors that are semipermeable - meaning that the water molecules can get through but not the larger sodium and chloride ions. Now some of the water molecules may go through one of these doors to go from party A to party B, and s...