Content
- What is broadcasting?
- Examples of diffusion
- What is osmosis?
- Because it is important?
- Examples of the osmosis process
Thediffusion and osmosis are phenomena characterized by the distribution of molecules of a body in another body that is in contact with that first or separated, but through a semi-plasma membrane. These two possibilities are precisely what opens the division between the two processes.
What is broadcasting?
Is the diffusion an intermixing of the molecules occurs, as a consequence of a movement that drives their Kinetic energy. The bodies are in contact, then the molecules are distributed, in a phenomenon explained by the kinetic theory of matter.
This motion occurs in any of the states of matter, but is more easily observed in the case of liquids. The tendency of the movement is towards the formation of a uniform mixture of the two types of molecules.
The scientist Adolf fick established in 1855 some laws that bear his name, and describe various cases of the diffusion of matter in a medium in which initially there is no equilibrium. These laws relate the flux density of the molecules to the difference in concentration between the two media separated by the membrane, the diffusion coefficient of the molecules and the permeability of the membrane.
Next, some cases of cell diffusion will be exemplified.
Examples of diffusion
- The passage of oxygen in the pulmonary alveoli.
- Nerve impulses, which involve sodium and potassium ions across the membrane of the axons.
- If a diffuser pair made up of two metals brought into contact across their faces is taken, and the temperature is brought below the melting point, it will be verified that the composition has changed: the nickel atoms have melted towards the copper.
- The warming and color change of a cup of coffee when a good proportion of cold milk is added.
- The entry of glucose to red blood cells, coming from the intestine.
- In an estuary, there is a less dense diffusion of river water that flows over seawater.
- If you put a tablespoon of sugar in a glass of water, the sucrose molecules diffuse through the water.
- The diffusion of gases can be seen when a perfumed person enters a closed place, and everyone immediately feels the smell. The same thing happens when someone smokes indoors.
What is osmosis?
The main characteristic of the semi-permeable membrane that gives rise to the process of osmosis is that it allows the passage of the solvent, but not the solute: it contains pores of molecular size that assign these characteristics.
In this way, it is observed that the solvent tends to pass through the membrane in the direction of the solution whose concentration is higher, which ends up producing that the amount of solvent increases in the more concentrated part and decreases in the less concentrated part. This is a process that is repeated until the hydrostatic pressure balances the trend.
Because it is important?
The solubility of the solute in the solvent and the nature of the membrane to be used are the fundamental factors that determine the effectiveness of the osmotic process: the so-called 'solubility' is determined by the chemical bonds that each component in the solution presents.
The osmotic process is fundamental in biological processes where water is the solvent, especially in those processes aimed at maintaining the water and electrolyte balance in living beings, regulating water levels in the cell or in the body in general: without this process, there could be no fluid regulation and nutrient absorption.
Examples of the osmosis process
- Single-celled living things that live in fresh water enter large amounts of water through osmosis.
- The absorption of water by the roots in plant organisms, which allows growth, occurs through a phenomenon of this type.
- Obtaining water from the epithelial cells, by the large intestine, is a process of this type.
- A common osmosis experiment consists of splitting a potato, placing a little sugar with water at one end and a plate with water on the other. The potato acts as a membrane, and after a while it will be seen that the solution that had sugar now has more liquid.
- The hormone ADH that allows the reabsorption of water by the collecting duct in the kidneys.
- The elimination of very dilute urine by which the fish expel the maximum liquid with the minimum loss of salts.
- The elimination of water through sweat in people is done through osmosis.
- Filters to purify water work with osmosis, since they are made with a material that allows water to pass, but not larger molecules.
