Question

Define : Tyndall effect / Brownian movement / Imbibition / Diffusion / DPD / Osmosis / Hypertonic solution / Hypotonic solution / Isotonic solution / Plasmolysis / Osmotic pressure / Turgor pressure / Wall pressure / Water potential / Permeability.

Answer 1

Diffusion: It is the random movement of molecules along the concentration gradient (from an area of higher concentration to an area of lower concentration) by their kinetic energy. It is a spontaneous and passive process.

Osmosis: It is a specialized case of diffusion that involves the passive transport of water (i.e. solvent ).In osmosis, water moves through a semipermeable membrane from a region of its higher concentration to a region of its lower concentration.

Turgor Pressure: When a plant cell is placed in a hypotonic solution, water diffuses into the cell causing the protoplast to build up a pressure against the wall. The pressure extended outwardly against the cell wall by the expanding protoplast is known as Turgor pressure.

Wall pressure: An equal but opposite inward pressure by the cell wall on protoplast is called wall pressure.

Plasmolysis: The shrinkage of the cytoplasm of a living cell as a result of exosmosis is known as plasmolysis.

Osmotic pressure: It is defined as the pressure required to completely stop the entry of water into an osmotically active solution across a semipermeable membrane. It is also defined as the minimum pressure needed to stop osmosis.

Water potential: It is the measure of the free energy of water per unit volume. It is commonly expressed in terms of pressure units such as Pascal.

Permeability: It is the property of the membrane to allow the passage of both solute and solvent molecules.

Tyndall effect: It is the phenomenon in which the particles in a colloid scatter the beams of light that are directed at them. This effect is seen by all colloidal solutions and a few very fine suspensions. The intensity of scattered light depends on the density of the colloidal particles as well as the frequency of the incident light.

Brownian movement: Brownian movement also called Brownian motion is defined as the uncontrolled movement of particles in a fluid due to their constant collision with other fast-moving molecules.

Imbibition: Imbibition is a type of diffusion where the water is absorbed by the solid particles called colloids, causing an enormous increase in volume. The solution is not formed in the process. In other words, water absorption by colloids is known as imbibition.

Hypertonic solution: A hypertonic solution has higher solute content than another solution. When a plant cell is placed in a hypertonic solution, water moves out and protoplast shrinks and cells become flaccid.

Hypotonic solution: A solution with a lower solute content than another solution is referred to as a hypotonic solution. When a plant cell is placed in a hypotonic solution, water enters into the cell protoplast and the cell becomes turgid.

Isotonic solution: An isotonic solution has the same solute content as another solution. When a cell is placed in an isotonic solution, there is no net flow of water towards the inside or outside.

DPD: DPD stands for Diffusion Pressure Deficit (DPD). It is the amount by which the diffusion pressure varies between two solutions. This is characterized as the amount by which the water or solvent diffusion pressure in a solution is inferior to that of pure water or solvent.

Water potential: The water potential is defined as the measure of free energy per volume. It is used to describe the direction of the movement of water.