What is osmosis class 9

Theory • Imbibition: It is a special type of diffusion in which movement of water takes place due to difference in water molecule concentration between the adsorbant and the imbibant. For e.g., the dry plant part or dry seeds when placed in water increases in size or swells. Mass percentage of water imbibed by raisins can be calculated as:Mass % of water imbibed=\(\frac X100\) Question 22: Some raisins weighed 10 g before they were placed in water for four hours. The raisins were then removed, wiped and weighed again. Their weight was found to be 12.5 g. The percentage of water imbibed by them is (a) 2.5% (b) 5% (c) 12.5% (d) 25% Question 23: On rainy days the wooden door of our house swells due to the process of (a) imbibition (b) osmosis (c) diffusion (d) transpiration Question 24: While performing an experiment with raisins, a student recorded the following data. Mass of water taken in the beaker = 50 g Mass of raisins before soaking = 20 g Mass of raisins after soaking = 30 g Mass of water in beaker left after experiment = 40 g The % of water aboserbed by the raisins is (a) 10% (b) 20% (c) 45% (d) 50% SCORING KEY WITH EXPLANATION • (b) The formula is constant. • (a) Dry grapes are called raisins. • (a) It is the method of the experiment. • (c) It is the method of the experiment. • (d) The water on the surface of the raisins is removed to calculate the accurate reading. • (a) The solution with more water is called hypotonic • (c) The solution with less water is called ...

Have you ever forgotten to water a plant for a few days, then come back to find your once-perky arugula a wilted mess? If so, you already know that water balance is very important for plants. When a plant wilts, it does so because water moves out of its cells, causing them to lose the internal pressure—called turgor pressure—that normally supports the plant. Why does water leave the cells? The amount of water outside the cells drops as the plant loses water, but the same quantity of ions and other particles remains in the space outside the cells. This increase in solute, or dissolved particle, concentration pulls the water out of the cells and into the extracellular spaces in a process known as osmosis. Formally, osmosis is the net movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. This may sound odd at first, since we usually talk about the diffusion of solutes that are dissolved in water, not about the movement of water itself. However, osmosis is important in many biological processes, and it often takes place at the same time that solutes diffuse or are transported. Here, we’ll look in more detail at how osmosis works, as well as the role it plays in the water balance of cells. This is actually a complicated question. To answer it, let’s take a step back and refresh our memory on why diffusion happens. In diffusion, molecules move from a region of higher concentration to one of lower c...

Objective Our objective is that to study osmosis using a potato osmometer. Theory What is Osmosis? Osmosis is the process in which solvent molecules moves through a semi-permeable membrane from a region of higher concentration to a region of lower concentration until the amount of fluid is equalised on both sides of the semipermeable membrane. The fluid that passes through the semipermeable membrane is known as the solvent, while the dissolved substance in the fluid is known as the solute. The mixture of solvent and solute makes up a solution. Cause for Osmosis Osmosis occurs due to the free energy of the solvent molecule in two regions. Pure water or solvent has more free energy compared to that present in a solution. Therefore during osmosis, solvent or water moves through the semipermeable membrane from a region of its high free energy to a region of its low free energy. Importance of Osmosis Osmosis plays a critical role in plant and animal cells. It helps in the distribution of nutrients and in the release of waste products. The living cells of both plant and animals are surrounded by a semipermeable membrane known as the cell membrane. The membrane forms a selective barrier between the cell and its environment and does not allow toxic substances from the surroundings to enter into the cell. The selective permeability allows the cell to regulate the flow of necessary substances into and out of the cell. In plants osmosis is also responsible for absorbing water and min...

Osmotic Pressure The minimum pressure required to prevent the inward flow of a solution’s pure solvent through a semipermeable membrane is known as the osmotic pressure. It’s also known as the osmosis index, which measures a solution’s inclination for absorbing a pure solvent. The highest osmotic pressure that a solution could create if separated from its pure solvent by a semipermeable membrane is known as potential osmotic pressure. When a selectively permeable membrane separates two solutions with varying solute concentrations, osmosis occurs. From a low-concentration solution to a solution with a higher solute concentration, solvent molecules move selectively through the membrane. Solvent molecules will continue to be transferred until equilibrium is reached. Table of Contents • • • • • • What is Osmotic Pressure? Osmotic pressure can be defined as the minimum pressure that must be applied to a solution to halt the flow of solvent molecules through a semipermeable membrane (osmosis). It is a Ï€ = iCRT Where, • Ï€ is the osmotic pressure • i is the • C is the molar concentration of the solute in the solution • R is the universal gas constant • T is the temperature This relationship between the osmotic pressure of a solution and the molar concentration of its solute was put forward by the Dutch chemist Jacobus van’t Hoff. It is important to note that this equation only holds true for solutions that behave like ideal solutions. Understanding Osmotic Pressure – What is O...

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. Created by Sal Khan. Unfortunatly, the previous answer was not correct. Facilitated diffusion refers to a type of passive diffusion (requires no energy) where channels are lined by proteins that facilitate the diffusion of larger molecules through a semi permeable membrane. In the video the instructor talks about the sugar molecules being too large to simply passively diffuse through the membrane. One way to allow those molecules (either prevented by size or hydrophilicity)to pass through this membrane is to place a protein channel that makes this passage possible. The actual process of diffusion is then an energetically free process. (We are not considering the energy costs associated with making the protein channel.) The previous poster was also incorrect when explaining pinocytosis. Pinocytosis is a type of cellular intake mechanism that can be described as a non-selective "gulp". The cell invaginates and takes in a relatively large quantity of the surrounding medium and digests any useable contents. This is done without the need for any receptor/ligand mechanism as is used in phagocytosis. I hope this helps! 15:00, why is it ...

Osmosis is the spontaneous movement or diffusion of water molecules from a region of higher concentration to a lower concentration through the semi-permeable membrane. However, osmosis can occur in other liquids too. A semi-permeable membrane is a membrane that allows certain particles according to their size to pass through them. For example, 2 FAQs on Osmosis Osmosis Definition This process was firstly introduced by German physiologist; Wilhelm Pfeffer however the term osmose (osmosis) was given by Thomas Graham in 1854. It is a passive movement which means that it takes place without using any cell Solutions However, there are only three types of osmotic solutions. These are as follows: 1. Hypotonic Solution In hypotonic solutions, the concentration inside the cell is lower than the concentration outside the cell. Meanwhile, due to lesser concentration, the liquid outside the cell comes inside causing the cell to swell up. For example- Distilled water. 2. Hypertonic Solution In hypertonic solutions, the concentration inside the cell is however higher than the concentration outside. As a result, the contents inside the cell move outside causing the cell to shrink. For example- Seawater, sugar drinks. 3. Isotonic Solution In an isotonic solution, both the cell solution and the medium solution have the same concentration. This way there is no flow of liquid and the solution remains the same. In other words, there is neither the shrinkage nor expansion of the cells. For exa...