Please explain Diffusion and Osmosis. And what is a concentration gradient?

Answer 1

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Concentration gradient: is a regular concentration change over a distance in a particular direction.
The net directional movement is away from the center of concentration. Diffusion is the net movement down the concentration gradient. Diffusion is caused by the following natural occurrences: thermal motion ( movement caused by the loss of heat ), random molecular movement, and an increase in entropy of the system. In a solution of many different substances each substance diffuses down its own concentration gradient independent of the others. Diffusion is a passive type of transport, it requires no additional energy to make it work. Osmosis is diffusion of water across a biological membrane.

Solutions: A solution is a mixture of a solute ( thing being dissolved) and a solvent ( thing doing the dissolving). Water is usually the solvent, hence the term aqueous solution.
Types of Aqueous Solutions:

1. Hyperosmotic: solution with the greater concentration of solute ( salt water compared to fresh water). If a cell from a salt water fish is placed in a beaker of fresh water, the cell is said to be hyperosmotic to the water.

2. Hypoosmotic: solution with a lesser concentration of solute ( fresh water compared to salt water). If a cell from a fresh water fish is placed into a beaker of salt water, the cell is said to be hypoosmotic to the water.

3. Isosmotic: solutions of equal solute concentrations are said to be isosmotic.

Water balance in a living cell:

1. Cells placed in a hyperosmotic environment ( salt water) animal cells crenate (shrivel). Plant cells plasmolyze (shrivel).

2. Cells placed in a hypoosmotic environment ( fresh water) animal cells lyse ( explode) and plant cell become turgid (firm).

3. Cells placed in an isosmotic solution animal cells are normal, plant cells are flaccid (limp).

Facilitated Diffusion: Passive form of transport caused by the help of carrier proteins specific for the molecules they transport. Movement is always down the concentration gradient. Polar molecules and ions are usually moved in this fashion.

Answer 2

Diffusion is the movement of a substance from an area of high concentration to an area of lower concentration caused by the random motion of particles of the substance. For example, When food coloring is put into yellow gelatin, the blue food coloring will diffuse through the yellow gelatin until both amounts are equal.

Osmosis is the diffusion of water. It basically deals with cells and the kind of solutions a cell can go through. Hypertonic solution is when water diffuses out of the cell. Hypotonic solution is when water diffuses into a cell and isotonic solutions are when water diffuses into and out of cells at equal rates.

Concentration gradient is a difference in the concentration. For reference to the blue food coloring and the yellow gelatin in above, the yellow gelatin has a higher concentration gradient than the blue food coloring.

Answer 3

Osmosis is diffusion, but with water only. The concentration gradient is the measurement of the difference in concentration between the two. Water usually crosses across a concentration gradient to dilute the area which is higher in concentration, in order to balance the total area.